Troubleshooting and Repairing Domestic Refrigeration and Air-Conditioning (DomRAC) Systems - LO-1 - plan and prepare for troubleshooting and repair

WEB SCRIPT HVAC
Sector:
Qualification: RAC Servicing (DomRAC) NC II
Unit of Competency: Troubleshoot and Repair Domestic Refrigeration and Air-Conditioning
(DomRAC) Systems
Module Title: Troubleshooting and Repairing Domestic Refrigeration and Air-
Learning Outcomes: Conditioning (DomRAC) Systems
Developer/s: LO1: Plan and prepare for troubleshooting and repair

Alvin P. Saulon

TITLE Planning and preparing for troubleshooting and repairing
OBJECTIVES
In this lesson you will be able know the importance of troubleshooting
INTRODUCTION chart, guide and table on repairing DomRAC units.
There is a close relationship between the terms troubleshooting &
servicing. Troubleshooting is often referred to as analysis of the problem.
This analysis is generally guided by a chart provided by the manufacturer
of the equipment. Servicing is the manual labor needed to correct the
problem that was identified in the troubleshooting sequence.

TOPIC 1 Troubleshooting chart, guide and table
Lesson 1 Troubleshooting chart, guide and table

One of the key requirements for service technicians is to follow standard procedure; the
example is as follows;

1. Obtain from the owner a description of the problem,
2. From the problem identified by the owner, determine the possible cause of the

problem,
3. Identify a specific remedy for the problem.

Using standard procedure will save time, money and frustration. Most charts have three (3)
basic columns, heading is;

a. Problem (trouble, complaint)
b. Possible Cause (probable cause, have gas checked….)
c. Remedy (Repair, you may need to)

When using the troubleshooting charts, it is important that the technician follow the chart on a
step-by-step basis.

Upon arrival at the location, the technician should become familiar with the system in questions.
The system should be visually inspected and all components and wiring examined for any evidence
of malfunction, the technician should then consider examination of the system’s electrical wiring &
component diagram.

When responding to service call the technician must always approach the problem in a logical
sequence.

• The first step in troubleshooting is to ask the owner/user or operator about the problem, then
inspect, check and test the system using troubleshooting instrument. Your ability to think the
problem of a cooling system is a great asset in troubleshooting.

Your five (5) senses can tell a lot about what is going on a system.

Look: for vibration, gauge reading, current and voltage reading, leaks, broken or loose
parts.

Listen: for compression knocks, valves opening or closing, switches clicking at the right
time.

Feel: feel temperature changes, pipes that are hot when they should be cool, or vice
versa.

Smell: for burned wire insulation, hot parts or belts slipping.
Taste: for food that has spoiled due to vacuum temperatures.

Owner’s Description of Problem

• The first column of the troubleshooting chart normally lists the problem. This column
would be the complaint given to the service technician by the owner – usually in general
terms.

• The technician logins troubleshooting by carefully listening to the owner’s complaint.

Checking Possible Cause

• The next step would be for the technician to check the possible cause column & to
analyze this listing in terms of the major components of the system.

• After a thorough investigation of the possible cause’s column, the technician proceeds
to identify the parts of the system listed as the possible cause of the problem or
symptom. The technician should then be able to determine a specific cause or
malfunction & to identify the specific faulty part.

Suggested Remedy

• The final column on the troubleshooting chart may have a heading of remedy. This is
the third (3rd) step when using troubleshooting chart. The technician will perform the
appropriate task for this column. The actual procedure will vary depending upon the
specific remedy selected, the type of part or device being checked & the specific
system. Basic service & safety procedures are always followed as the technician
repairs the system.

Troubleshooting Chart
• Servicing must always accomplish through the use of the proper tools, gauges,
electrical analyzing equipment & other necessary equipment.
• The use of troubleshooting charts is relatively simple. The technician must understand
it is a helpful map which leads from step 1 – Problem, step 2 – Possible Cause, & step
3 – Remedy.
• One must be very careful to utilize the specific troubleshooting chart the manufacturer
of the equipment being serviced. Troubleshooting charts vary, depending upon the

purpose of the equipment & the particular manufacturer. The troubleshooting chart is
broken down into the basic columns; Complaints, Possible Cause & Repair.

COMPLAINT POSSIBLE CAUSE REPAIR
A. Compressor will not 1. Line disconnect switch 1. Close start or disconnect

start – no hum open. switch.
2. Fuse removed or blown 2. Replace fuse.
B. Compressor will not 3. Overload protector tripped 3. Refer to electrical diagram.
start – hums 4. Control stuck in open 4. Repair or replace control.
5. Relocate control.
position. 6. Check wiring against
5. Control off due to cold
diagram.
location.
6. Wiring improper or loose. 1. Check wiring against
1. Improperly wired. diagram.

2. Low voltage to unit. 2. Determine reason and
correct.
3. Starting capacitor
defective. 3. Determine reason and
replace.
4. Relay failing to close.
5. Compressor motor has 4. Determine reason and
correct, replace if
winding open or shorted. necessary.
6. Internal mechanical trouble
5. Replace compressor.
in compressor. 6. Replace compressor.

C. Compressor will not 1. Improperly wired 1. Check wiring against
start – hums but 2. Low voltage to unit. diagram.
trips on overload 3. Relay failing to open.
protector. 2. Determine reason & correct.
4. Run capacitor defective. 3. Determine reason & correct,
D. Compressor starts 5. Excessively high discharge
and runs, but short replace if necessary.
cycles on overload pressure. 4. Determine reason & replace
projectors. 6. Compressor motor has a 5. Check discharge shutoff,

winding open or shorted. possible overcharge.
7. Internal mechanical trouble 6. Replace compressor.

in compressor (tight). 7. Replace compressor.
1. Additional current through 1. Check wiring diagram, check

overload protector. for added fan motors,
pumps, etc., connected to
2. Low voltage to unit. wrong side of protector.
2. Determine reason and
3. Overload protector correct.
defective. 3. Check current, replace
protector.
4. Run capacitor defective. 4. Determine reason and
replace
5. Excessive discharge 5. Check ventilation, restriction
pressure. in cooling medium, restriction
in refrigeration system.

6. Check for possibility of

6. Suction pressure too high. misapplication, use stronger

unit
7. Compressor too hot – return 7. Check refrigerant charge (fix

gas hot. leak), add if necessary.

8. Compressor motor has a 8. Replace compressor.

winding shorted.

E. Unit runs ok, but 1. Overload protector 1. See D
short cycles. 2. Thermostat 2. Differential set too close –

3. High pressure cut-out due widen.

to:

a. Insufficient air. 3a. Check air to condenser
–correct.

b. Overcharge. 3b. Reduce refrigerant

charge.

c. Air in system 3c. Purge

4. Low pressure cut-out due to:

a. Undercharge 4a. Fix leak, add refrigerant.

b. Restriction in 4b. Replace device

expansion device.

Quiz 1: TRUE OR FALSE: Write TRUE if the statement is true and FALSE if the statement is false

1. When responding to service call the technician must always approach the problem in a logical
sequence.

2. The first column of the troubleshooting chart normally lists the problem. This column would be
the complaint given to the service technician by the owner – usually in general terms.

Static electricity
3. After a thorough investigation of the possible cause’s, the technician proceeds to identify
the parts of the system listed as the possible cause of the problem or symptom.

4. The use of troubleshooting charts is relatively simple. The technician must understand it is a
helpful map which leads from step 1 – Problem, step 2 – Possible Cause, & step 3 – Remedy.

5. The technician logins troubleshooting by carefully listening to the owner’s complaint.

TITLE Planning and preparing for troubleshooting and repairing
OBJECTIVES
INTRODUCTION In this lesson you will be able identify and understand how the seven
basic refrigeration components function

TOPIC 2 Parts of Refrigeration Circuit

Lesson 1 Seven Basic Refrigeration Components

SEVEN BASIC REFRIGERATION COMPONENTS

1. Motor Compressor
2. Condenser
3. Refrigerant flow Control/Metering Device
4. Evaporator
5. Discharge Line
6. Liquid Line
7. Suction Line

1. Compressor

A compressor acts as the “heart” of a refrigerant-based mechanical cooling system. Its functions
include drawing in the cool vaporized refrigerant that carries the heat energy from the evaporator
coils, compressing it from a low pressure and temperature to a high pressure and temperature, and
pushing it around the refrigeration loop for the purpose of heat rejection.

a visual representation of a motor compressor for Air conditioning (left)
and refrigeration unit (right)

a visual representation of a cut-away view and operation of compressor
2. Condenser
Refrigeration in real sense is simply moving heat from a place where it is not wanted to a place where
it is not objectionable. The condenser is a device used for removing heat from the refrigeration
system. It is a component which transfers the heat from the refrigeration system to a medium which
has lower temperature than refrigerant present in condensers; it can absorb and move heat to an
ultimate disposal point. The condenser is the door opening provided to transfer unwanted heat out of
the refrigeration system. Air and water are the two-basic media in which condensers could reject their
heats. These two are selected because they are usually available in sufficient quantities and are
cheap. They are also easy to handle and are not dangerous. Their normal temperature range is also
satisfactory for liquification of refrigerant.

a visual representation of fin coil type condenser

3. Refrigerant Flow Control/Metering Device
Refrigerant flow control is used to fine-tune the temperature in refrigerant devices by maintaining an
optimal flow of refrigerant into its evaporator. Refrigerant flow control technology is used in everything
from air conditioners to refrigerators in order to keep stable, cooled temperatures in closed areas

a visual representation of capillary tube (left) and thermostatic expansion valve (right)
4. Evaporator
The evaporator is that part of the low-pressure side of the refrigeration system in which the liquid
refrigerant boils or evaporates, absorbing heat as it changes into a vapor. It accomplishes the actual
purpose of the system, refrigeration.

a visual representation of evaporator for refrigeration unit
CONNECTING PIPELINES IN REFRIGERANT CIRCUIT
5. Suction Line
The suction line is the part of the piping system of an ac/ref unit. After the refrigerant evaporates into
a gas in the evaporator coil the section of piping from this coil to the compressor is called the suction
line.

The suction line caries the refrigerant vapor from the evaporator to the compressor. The line must be
large enough to carry the vaporized refrigerant with minimal flow resistance.

6. Discharge Line

Discharge gas lines (often referred to as hot gas lines) allow refrigerant to flow from the discharge of
the compressor to the inlet of the condenser.

7. Liquid Line

This is the pipe connecting the outlet of condenser and inlet of metering device.

Lesson 2 Operation of Window-Type Air-Conditioning Unit

Air conditioning unit is a control system for temperature, humidity, air movement and air cleaning in
a confined space. The unit can control the temperature by absorbing the heat inside the room. How
does it happen?

First, to fully understand how window-type air-conditioning system works, we need to learn some
thermal laws related to refrigeration and air-conditioning:

1. Fluids absorb heat while changing from a liquid state to a vapor state and give up heat in
changing from a vapor to liquid.

2. Heat flows only from a body which is at a higher temperature to a body which is at a lower
temperature (hot to cold)

These laws will help us fully understand the operation of the window-type air conditioning system.
Now we can start to discuss the operation of window-type air-conditioning.

As we set the unit to fan mode, we are supplying power to the fan motor. The movement of the fan
motor will suck air from the air filter side blowing it out to the evaporator side (compressor is still off
therefore no movement on refrigerant line). This process circulates the air from the room and filters
it.

The thermostat is a thermal sensor which can be set. Once the temperature of the evaporator varies,
and the setting of the thermostat becomes the same with the temperature, it automatically turns off
the compressor (provided that the compressor is running) then turns it on again when the temperature
becomes warmer.

As we set the unit into cool mode, we are energizing the motor compressor. The compressor will
force the refrigerant to circulate through the system. The refrigerant will flow from discharge line,
passing through the condenser, to the metering device, then going to the evaporator and returning
to the suction line of the compressor. This completes the cycle. So how is heat absorbed?

Warm filtered air passing to
the evaporator side then
returning to the room

a visual representation of an operation of window-type air-conditioning unit

The refrigerant from the discharge line is a high-pressure vapor. And we know that high pressure
vapor is directly proportional to temperature making the temperature in the condenser hot. The air
which had been suck by the condenser fan from outside of the room is a little bit lower compared to
the temperature of the condenser. This will now cool down the temperature of the refrigerant in the
condenser as stated in law number two (2); Heat flows only from a body which is at a higher
temperature to a body which is at a lower temperature (hot to cold). As the condenser gives off heat
to the surrounding medium, the refrigerant changes state from gas to liquid but still it is high
temperature high pressure liquid as stated in law number one (1); Fluids absorb heat while changing
from a liquid state to a vapor state and give up heat in changing from a vapor to liquid.

The liquid will now pass through the metering device where pressure will drop through its
throttling effect. Again, as we know, if the pressure decreases, temperature also decreases. As a
result, the refrigerant absorbs heat (air coming from the room sucked by the evaporator fan) from
room. When the refrigerant absorbs heat, it boils and changes its state from liquid to vapor as stated
in law number (1); Fluids absorb heat while changing from a liquid state to a vapor state and
give up heat in changing from a vapor to liquid.

As low temperature low pressure vapor travels down the suction line it continues to absorb heat
turning it to superheated refrigerant. When the refrigerant enters the suction line and passing to the
compressor, it becomes more superheated. It continues to be superheated until such time that it
reaches the first coil of condenser. This cycle keeps on repeating until desired temperature of the
room is achieved

Quiz 1: MULTIPLE CHOICE: Identify the correct word/s on the following statement. Encircle the
letter of the correct answer.

1. I t acts as the “heart” of a refrigerant-based mechanical cooling system.
A. Condenser
B. Evaporator
C. Motor Compressor

D. Refrigerant Flow Control/ Metering Device

2. Is a device used for removing heat from the refrigeration system.
A. Condenser
B. Evaporator
C. Motor Compressor
D. Refrigerant Flow Control/ Metering Device

3. It is used to fine-tune the temperature in refrigerant devices by maintaining an optimal flow of
refrigerant into its evaporator
A. Condenser
B. Evaporator
C. Motor Compressor
D. Refrigerant Flow Control/ Metering Device

4. It is the part of the low-pressure side of the refrigeration system in which the liquid refrigerant
boils or evaporates, absorbing heat as it changes into a vapor
A. Condenser
B. Evaporator
C. Motor Compressor
D. Refrigerant Flow Control/ Metering Device

5. It is a gas lines (often referred to as hot gas lines) allow refrigerant to flow from the discharge
of the compressor to the inlet of the condenser.
A. Discharge Line
B. Extension Line
C. Liquid Line
D. Suction Line

Answer Key:

Multiple Choice

1. C.
2. A.
3. D.
4. B.
5. A.

TITLE Planning and preparing for troubleshooting and repairing
OBJECTIVES
In this lesson you will be able to identify and interpret manufacturers
INTRODUCTION name plate.
Nameplates provide useful information about equipment. Among other
TOPIC 3 things, the information can be used to understand energy use, find
Lesson 1 compatible or more efficient replacements for equipment and
General Information: troubleshoot problems. This fact sheet provides details about types of
information found on nameplates.

Manufacturers Nameplate Overview

Basic Nameplate Information

Most equipment nameplates will have some common items of information. Many of these are self-
explanatory, and include:

• Manufacturer
• Manufacturer’s address
• Model number
• Serial number
• Certification mark(s)

This general information can be useful in finding out more details about particular through the
manufacturers published information. Various certification marks are shown below.

AIR CONDITIONING MANUFACTURER’S NAMEPLATE

a visual representation of air-conditioning (left) and refrigeration (right) nameplate

To begin, we have the model number. This is usually printed on a label on the system, which is
often located on the inside of the access panel or it will be on the inside or outside wall of the unit.
Frequently, this will also be where the serial number will be located. The model number usually
indicates the heating or cooling capacity, but on newer systems the cooling capacity can also be
stated separately.

The model number will indicate the tonnage of the air conditioning or heat pump system. Tonnage
is a unit of measure that is used to describe the cooling or heating capacity of a system. A ton of
cooling is based upon how much heat is needed to melt one ton (which is 2000 lbs.) of ice in 24
hours. A ton of cooling equals 12,000 BTU/hour. BTU is short for British Thermal Unit. For example,
if a system is 30,000 BTU/hour, it is said to be a 2.5-ton system. Within the model number, there
will be a number that is divisible by 12. That number will determine allow you to determine the
tonnage of the system. If you see the number 30 in the model number, that will tell you that your
system is 2.5 tons.

If you have a newer system, the cooling capacity will generally be indicated directly on the
nameplate. Usually, the nameplate will be located on a sticker on the outside or inside of the unit.

Also, frequently listed on the nameplate is the voltage. The voltage indicates how much electricity
the system uses. The voltage of a system will remain constant regardless of the load that is placed
on it. However, as more of a load is placed on the system, the current will increase. As a result, the
number of watts used will increase. Additionally, you may also see how many phases your system
is. For most residential applications, it will be single phase.

Another important piece of information on the nameplate will be the Rated Load Amperage, often
times labeled as RLA. This is a calculation that is used to get approval by the Underwriters
Laboratories for a compressor motor. You will also see the Full Load Amperage, often labeled as
FLA. With an increase in load on a motor, the total amperage needed to power the motor
increases. When the full load of the motor is reached, the total amperage that the motor is drawing
at this point is the full load amperage, or FLA. This is a value that is used in order to size field wires
and fuses.

Next, the serial number, which is usually located on the nameplate, can tell you some important
information as well. While this may look like a long string of numbers and letters that do not mean
anything, they sometimes can tell you the age of your system. The serial number of a unit means
different things on different systems. In general, the serial number will tell you the age of your
system.

Another common and important piece of information on your system is its Energy Efficiency
Ratio. This information tells you how much electricity you use to obtain a certain amount of cooling.
The unit of measure for this is KW per hour of electricity used/1,000 BTU’s. You will usually be able
to find this information on an Energy Guide sticker that is bright yellow and often located on the side
of the system. This sticker will tell you your estimated yearly operating cost as well.

Refrigerant name and quantity are the type of refrigerant and the amount of refrigerant charged
in the system.
The easiest way to establish the amount of refrigerant in the system is to use data supplied by the
manufacturer:
• Many refrigeration systems, especially small ones, have a Name Plate showing the amount of
refrigerant.
• Alternatively, you may have a record of the amount of refrigerant in the documentation supplied
when the system was installed.

On a Name Plate there will be a refrigerant name (which will enable you to establish whether the
refrigerant is a HCFC, HFC and also a refrigerant charge, shown in grams or kilograms. The name
plate shows the type of data you are likely to find. Half way down the right side of the label (inside
the oval) it shows the refrigerant used is R-22 and the quantity is 893 grams.

Quiz 1: Enumeration: List down at least 5 information you can find in an air conditioning nameplate.
1. Brand Name
2. Model Number
3. Serial Number
4. Manufacturer’s Address
5. Full Load Ampere (FLA)
6. Energy Efficiency Ratio (EER)
7. Type and amount of refrigerant charged

WEB SCRIPT HVAC
Sector:
Qualification: RAC Servicing (DomRAC) NC II
Unit of Competency: Troubleshoot and Repair Domestic Refrigeration and Air-Conditioning
(DomRAC) Systems
Module Title: Troubleshooting and Repairing Domestic Refrigeration and Air-
Learning Outcomes: Conditioning (DomRAC) Systems
Developer/s: LO2: Identify and Repair Faults/Troubles

Alvin P. Saulon

TITLE Planning and preparing for troubleshooting and repairing
OBJECTIVES
In this lesson you will be able to troubleshoot and repair electrical parts,
INTRODUCTION components of DomRAC units.
Some AC electrical problems can arise solely from broken electrical parts
and faults in the wiring that services it. These are some of the common
parts and problems that lead to electrical failure.

TOPIC 1 Electrical parts, components troubleshooting and repairing

Lesson 1 Issues with electrical parts

Loose Wire
Within your air conditioner itself, there are many electrical parts that bring power to different parts of
the unit. If any of these wires come loose over time or with excess wear, it can disrupt power flow to
those parts.

Wrong Fuse
If you’ve already self-repaired, or had your AC electrical system serviced by someone other than a

professional, you might now have incorrect replacement parts in your unit. This includes the wrong

type or size fuse/circuit breaker for your specific HVAC system.

Dirty Fuse

Just like filters need to be cleaned to allow the flow of air, fuses need to be kept clean to allow the
flow of electricity. If your unit hasn’t been properly maintained, debris can block the connection

between fuses.

Bad Capacitor
The capacitor is an essential part of the AC electrical system. It stores charges and regulates the
power to the system. If the capacitor is failing, you could experience recurring AC electrical
problems.

Short in Wiring
When wires receive more electricity than they were designed to handle, they can short out. This can
happen due to a power outage in a storm, or the wires could weaken over time. This blocks the flow
of electricity and causes a fire hazard.

Electric bill suddenly goes up
You might be tipped off to any of the above problems if your electric bill suddenly skyrockets. AC
electrical usage can comprise a significant portion of your regular electric bill, so if your air
conditioner suddenly runs more often or uses more energy than before, than you will see that

change reflected in your bill. Keep track of significant changes and be aware of AC electrical
problems before they lead to breakdowns.

AC Won’t Turn Off
If your air conditioner is constantly running and struggling to reach a desired temperature, it might
not be electrical damage at all. Buildings that skimp on AC maintenance are likely to develop
symptoms that resemble AC electrical problems. An accumulation of dust and grime in your filter
can make your AC struggle to keep cool and run constantly. This could lead to frozen coils, so keep
up your regular maintenance.

Common Troubles of Compressor Motor Connections

Compressor motor fails to start…
A) No humming.
1. No power
2. Open overload protector
3. Open running winding
4. Loose connections
5. Open coil of current relay

B). With humming.
1. Low voltage  10% of power supply
2. Shunted winding
3. Open starting winding
4. Grounded winding
5. Tight/stuck-up compressor
6. Defective starting capacitor
7. Defective running capacitor
8. Defective starting relay (open contact)
9. Loose connection

C) Start and run by cycles on Overload Protector.
1. Low voltage: 10% of power supply
2. Relay does not get-off starting winding
3. Weak overload protector
4. Additional current flowing in overload protector
5. Shunted winding
6. Tight compressor
7. Grounded windings
8. Defective capacitor

Task Sheet 1: Checking Electrical Windings and Test Run Motor Compressor
Given a qualification, you should be able to check condition of
Performance compressor electrical windings.
Objective:
Supplies/Materials: Paper, Marker, Masking tape, Gloves, Goggles, Clean rag

Equipment/Tools: Analog/Digital Ohmmeter, DomRAC unit Screwdrivers, Longnose plier

Steps/Procedure:
1. Switch OFF the unit and unplug from power
source
Note: Do not remove the power plug by
pulling by the cord.

a visual representation of unplugging from power source

2. Disconnect the wiring connection of compressor
motor.

a visual representation of disconnecting wiring connection
3. Check for resistance and continuity

• Set the multimeter to Rx1 and calibrate the
meter through zero ohm adjust knob for
analog tester

• Set digital multi meter to resistance Ω.

a visual representation of calibrating voltmeter

4. Put label/tag on terminal of compressor using masking tape.

1

23

a visual representation of tagging/labelling motor compressor terminal

5. Record the resistance reading obtained from the different terminals.
Using the formula:
S + R terminals = highest reading
C + S terminals = second highest
C + R terminals = lowest reading

TERMINAL RESISTANCE
2&3 20 Ω
1&2 15 Ω
1&3 10 Ω

a visual representation of CSIR electrical connection

Based on the resistance Terminal 1 = Common (C)
Terminal 2 = Starting (S)
Terminal 3 = Running (R)

Note: If the resistance reading did not conform to the formula, compressor motor winding is
defective.

6. Set the ohmmeter to Rx10K. calibrate the meter to zero and place the test prod to common
terminal and compressor body.
Note: If the pointer deflects, the compressor is grounded. If the pointer did not deflect, the
compressor winding is not grounded (good).

a visual representation of checking motor compressor for grounding defect
7. Observe the following data of winding resistance to indicate possible compressor troubles.
8. Proceed to test run motor compressor using the wiring diagram below.

a visual representation of PSC wiring connection

M

L
S

a visual representation of CSIR wiring connection

1. Have your instructor check your work.
2. Perform housekeeping.

Performance Criteria Checklist

CRITERIA YES NO
Did you …?

1. Switch OFF the unit and unplug from power source?
2. Disconnect the wiring connection of compressor motor?
3. Put label/tag on terminal of compressor using masking

tape?

4. Record the resistance reading obtained from the different
terminals?

5. Identify compressor motor terminal correctly?

6. Check compressor winding for grounding?

7. Test run motor compressor using PSC and CSIR
connection?

8. Did you perform housekeeping?

Trainer’s Signature:
Comment/Feedback:

Task Sheet 2: Identify Terminal Leads Using an Ohm Meter and Test Run a 3-Speed
Fan Motor
Performance Given a qualification, you should be able to identify and test run fan
Objective: motor
Supplies/Materials: Paper, Marker, Masking tape, Gloves, Goggles, Clean rag

Equipment: Analog/Digital Ohmmeter, AC Unit, Fan motor

Steps/Procedure:

Terminal leads of fan motors are identified by color-coding and by the resistances of the
windings. The colors of the terminal leads may fade, making them hard to identify. The terminal
leads may have to be identified by the resistances of the windings.

1. Switch OFF the unit and unplug from power
source
Note: Do not remove the power plug by
pulling by the cord.

a visual representation of unplugging from power source

2. Disconnect the wiring connection of fan motor.

a visual representation of disconnecting the wiring connection of fan motor

3. Check for resistance and continuity
• Set the multimeter to Rx1 and calibrate the meter
through zero ohm adjust knob for analog tester
• Set digital multi meter to resistance Ω.

a visual representation of calibrating voltmeter
4. Label the terminal leads from 1 to 5 as shown below. Use masking tape.

a visual representation of tagging/labelling fan motor terminal
5. Make a table like the one below to record the resistances of the different terminal lead

combinations.
TERMINAL RESISTANCE RANK
S (OHMS)

1 1&2
2 1&3
3 1&4
4 1&5
5 2&3
6 2&4
7 2&5
8 3&4
9 3&5
10 4 & 5

6. Measure and record the resistances of the different terminal lead. Use the table prepared in
Step 5.

7. Rank the readings from highest to lowest, making the highest reading as rank 1 and the
lowest as rank. 10.

a visual representation of windings of a 3-speed fan motor

Characteristics of the Windings
Terminal:
A and C - highest resistance
A and L - second to the highest
H and M - is equal to M and L
C and H - higher than H and M or M and L
8. The terminal lead found both on the highest (Rank 1) and second highest resistance (Rank
2) is the auxiliary terminal lead
.
NOTE:
If there is no terminal lead found on both the highest and second highest resistance, check
the values by measuring the resistance of the terminal leads again.
a. With the auxiliary terminal lead now identified, the other terminal lead on the highest

reading (Rank I) is the COMMON terminal lead.
b. The other terminal lead on the second to the highest reading (Rank 2) is the LOW terminal

lead.
9. Using the LOW terminal lead now as the reference terminal, measure the resistance of the

two remaining terminal leads.

a. The one with the higher resistance is the HIGH terminal lead.
b. The other unidentified terminal is the MEDIUM terminal lead.
10. Using now the LOW terminal lead as the reference point, measure the resistance of the other
terminal leads.
NOTE:
If the terminal leads are identified correctly, they must follow the table below.
Terminals
L and A - highest resistance
L and C - second highest resistance
L and H - second lowest resistance
L and M - lowest resistance
NOTE:
If the readings of the resistances do not follow the pattern above, repeat identifying the
terminal leads.
11. After terminal leads of fan motor identified, perform test run fan motor using the diagram
below

a visual representation of wiring connection of test run fan motor
12. Before energizing the circuit check the resistance on the plug. Resistance (Ω) reading

should follow the table below.

SELECTOR SWITCH RESISTANCE READING
POSITION
No Resistance/Continuity reading
OFF Either highest/second highest Ω
FAN reading it depends on the
manufacturer setting
LOW COOL Highest Ω reading
MEDIUM COOL Second highest Ω reading
HIGH COOL Lowest Ω reading

Note:
a. If the reading of the resistance is diff. from the guide on the table check your
connection.
b. If the connection of the Starting and Common terminal of fan motor was interchange
the rotation of the motor will also reverse.

13. Have your instructor check your work.
14. Perform housekeeping

Performance Criteria Checklist

CRITERIA YES NO
Did you …?

1. Switch OFF the unit and unplug from power source?
2. Disconnect the wiring connection of fan motor?

3. Put label/tag on terminal of fan motor using masking tape?

4. Record the resistance reading obtained from the different
terminals?

5. Rank the readings from highest to lowest, making the
highest reading as rank 1 and the lowest as rank. 10?

6. Identify the Starting and Common terminal from the highest
and second highest rank?

7. Use the LOW terminal lead as the reference terminal, to
measure the resistance of the two remaining terminal
leads?

8. Perform test run fan motor using the given wiring diagram?

9. Check the resistance reading on the plug before
energizing?

Trainer’s Signature:
Comment/Feedback:

TITLE Identify and repair faults/troubles
OBJECTIVES
In this lesson you will be able to troubleshoot and repair mechanical
INTRODUCTION parts, components of DomRAC system.
The main concept and procedures of each operation is the same for all
refrigeration and air-conditioning systems. They differ only in each
system specific connectivity requirements or tools to be used.

TOPIC 2 Mechanical parts, components troubleshooting and repairing
Lesson 1 overview
Mechanical parts, components troubleshooting and repairing
overview

Most of servicing and troubleshooting activities to RAC systems –dealing with refrigerants – falls
within the one of the following main operations:

▪ Recovery of Refrigerant (will be discuss in the next Learning outcome)
▪ Flushing
▪ Nitrogen charging (OFDN)/Leak Detection
▪ Evacuation
▪ Charging

What is flushing?
Flushing is performed in order to remove all contamination (dirt) from the system. The smallest
particle of contamination cause restriction and problems for a good function of the replaced
compressor. It takes less than 1/10 of a teaspoon of debris (dirt) to completely restrict flow of
refrigerant and oil in the typical auto AC system. Cleanliness and proper flushing procedures are
very important

Why / When flushing?
The AC compressor is the only moving part in the entire system and the only reason for oil in the
system. The oil is being circulated throughout the system, that means that all the components
(condenser, hoses, tubes, evaporator, drier, accumulator) have some coating of oil internally. If any
dirt, debris or contamination happened in the system all components are affected. Removing the oil
(and oil film inside the components) will eliminate all of the contamination from the AC system. It’s
the oil that attracts and holds contaminants within the system. Remove the old oil = remove the
contamination.

Nitrogen charging (OFDN)/Leak Detection
RAC systems are designed to operate adequately with a fixed charge of refrigerant. If it has been
determined that a system has insufficient refrigerant, the system must be checked for leaks, then
repaired and recharged. If no refrigerant was found in the system.

a visual representation of a nitrogen cylinder tank with pressure regulator

EVACUATION
A refrigerating system must contain only the refrigerant in liquid or vapor state along with dry oil. All
other vapors, gases, and fluids must be removed. Connecting the system to a vacuum pump and
allowing the pump to run continuously for some time while a deep
vacuum is drawn on the system can best remove these substances. It is sometimes necessary to
warm the parts to around +50°C while under a high vacuum; in order to accelerate the removal of
all unwanted moisture, heat the parts using warm air, heat lamps, or water. Never use a brazing
torch. If any part of the system is below 0°C, the moisture may freeze and it will take a considerably
longer time for the ice to sublimate to vapor during the evacuation process.
The equipment necessary to carry out the evacuation is:

• vacuum pump
• manifold gauges two servicing valves

(in the case system is not equipped with servicing valves)
• vacuum gauge.

CHARGING
System charging is adding the proper quantity of refrigerant to refrigeration system so that it
operates as intended. For a given set of conditions (design conditions) systems have an “optimum”
charge – this is the mass of refrigerant that the highest efficiency and design cooling capacity (or
heating capacity, in the case of a heat pump) will be achieved. At off-design conditions, for
example, at a higher or lower ambient temperature, the optimum charge will be different. However,
it is best to add the specified charge since this is what the system has been designed to handle.

a visual representation of a vapor refrigerant charging

a visual representation of a liquid refrigerant charging

Common Issues with AC System

1. Undercharge
2. Overcharge
3. Non - Condensable in system
4. Restricted metering device
5. Dirty or restricted air flow over condenser
6. Restricted air flow over evaporator

Job Sheet: System Reprocess
Performance
Objective: Given a qualification, you should be able to perform system reprocess
Paper, Marker, Masking tape, Gloves, Goggles, Clean rag, Lubricants
Supplies/Materials: Refrigerants, Gasses, Electrical Controls, Abrasives, Manuals

Equipment/tools: Flaring tool, Swaging tool, Tube cutter, Tube bender, set of pliers, set of
Steps/Procedure: screw drivers, Types of wrenches, Vise grip, Hack saw, Linear
Measuring Instrument, Pinch off tool, Vacuum pump motor
Recovery/ Recycling unit, Oxy- Acetylene welding w/ complete outfit
Refrigerator, Window type aircon, Gauge manifold w/ hoses, Electronic
leak detector, Thermometer

I. Pressure Leak test
The system should be tightness tested (i.e., “leak tested”). This can be done by pressurizing
the system with oxygen free, dry nitrogen (OFDN). Shut off the supply of nitrogen and check

the pressure over a period of time (a minimum of 15 minutes, but it depends upon the size of

the system; a larger system requires more time). Keep checking the pressure gauge to see if

the pressure reduces.

1. Connect low pressure gauge port to the system's low side service port.
2. Connect center hose of the manifold gauge set to the nitrogen cylinder's pressure

regulator port.
3. Open the nitrogen cylinder valve.
4. Open (turn clockwise) nitrogen pressure regulator until pressure reaches 150 psi.
5. Then open low side valve at manifold gauge set to transfer nitrogen into the

refrigeration system up to 150 psi.
6. Close low pressure valve at the manifold gauge set when it reaches 150 psi.
7. Isolate the system by closing the nitrogen pressure regulator first and by closing the

valve at the top of nitrogen tank.
8. Disconnect the center hose (Yellow) and release the pressure slowly.
9. Observe the pressure gauge at manifold gauge set. If leak exists, pressure will drop.

Note: A minimum of 15 minutes, but it depends upon the size of the system; a larger
system requires more time. Keep checking the pressure gauge to see if the pressure
reduces. Take note of the following:

Leak Test Psig
Time Start: Psig
Time Finish:

10. Apply soap and bubbles to joints and fitting connection while observing the pressure.
Note:
If the pressure does fall, it is likely that the system has a leak, so leak searching and
repair procedures must be carried out.

11. When the system is confirmed to be leak-tight, release the OFDN in controlled
manner.

II. Perform Evacuation
To evacuate and dehydrate a system, before filling with refrigerant, take the following steps:

a visual representation of system evacuation/dehydration

1. Check vacuum pump oil level.
2. Connect low pressure gauge port to the system's low side service port.
3. Connect the high-pressure gauge port to the system's high side service port. (If

available)
4. Connect center port at the manifold gauge set to the vacuum pump.
5. Open the low-pressure valve at manifold gauge set.
6. Open high-pressure valve at manifold gauge set. (If connected to the system)
7. Open the vacuum pump valve
8. Plug to a power source and turn on vacuum pump and wait.

9. When satisfactory vacuum has been reached (29-30” Hg or 500-1000 microns)

close valve and turn off the pump and leave it for an appropriate length of time (15-30

mins for a small hermetic system, to several hours for a large site-installed

system) to see if the vacuum gauge indicates an increase in internal pressure.

Record the pressure and time start of observation.

Evacuation

Time Start: Psig

Time Finish: Psig

Note:
If the pressure rises there could be two reasons for it: either there is a leak or
moisture still in the system. In this case, the evacuation procedure should continue,
but if a constant vacuum pressure is never achieved, then it is likely that a leak is
present and the tightness test should be repeated.

10. If the vacuum pressure remains constant over a period of time, the circuit is correctly

evacuated; dry and free of leakage. Record the pressure and time finish of

observation

Evacuation

Time Start: Psig

Time Finish: Psig

11. Close low pressure and high-pressure valve at manifold gauge and removes the
vacuum pump.

III. Charging Refrigerant

1. Turn on and set weight scale to zero.

2. Weigh and record the initial weight of refrigerant cylinder.

Note:

The amount of refrigerant based on manufacturers nameplate must be obtained and will be

deducted from the initial weight of refrigerant cylinder.

Tank Weight

Before grams

After grams

3. Connect center hose at manifold gauge set to the refrigerant cylinder.
4. Open output valve at the refrigerant cylinder.
5. Purge the hose with small amount of refrigerant.
6. Open low-pressure valve at manifold gauge set to allow the refrigerant transfer to the

refrigeration system by the pressure inside the refrigerant cylinder.
Note:
Amount of refrigerant based on nameplate can be charged into the system.
7. Switch on the DomRAC unit to allow the refrigerant transferred to the refrigeration system by
using suction force from compressor until desired refrigerant weight is achieved.
8. After 30-60 minutes of running observe and record all operating parameters. (Operating
parameters is will be discussed on the last learning outcome of this module)
9. Close output valve at refrigerant cylinder.
10. To avoid venting of refrigerant to the atmosphere, open the low side valve at manifold gauge
set until the remaining refrigerant on the center hose (Yellow) is transferred inside the
system. Observe the low side gauge.
11. Disconnect hose all connection.
12. Weigh, record and put label using masking tape on the refrigerant cylinder.

Tank Weight

Before grams

After grams

Performance Criteria Checklist

CRITERIA YES NO
Did you …?

1. Connect all hoses correctly during leak test?
2. Set nitrogen pressure regulator to 150 psi before charging

to the system?

3. Close all valves after charging nitrogen in the system?

4. Record the time and pressure of system during leak test?

5. Check vacuum pump oil level before using?

6. Connect all hoses and open all valves for evacuation?

7. Record the time, vacuum pressure and close vacuum
pump valve after reaching 29”-30” Hg or 500-1000
microns?

8. Conduct observation on vacuum pressure for 15-30
minutes?

9. Weigh refrigerant cylinder before charging?

10. Purge center hose before charging refrigerant into the
system?

11. Charge correct amount of refrigerant according to
manufacturer’s nameplate and run the unit?

12. Collected DomRAC operating parameters after 30-60 mis
of continuous running?

13. Perform housekeeping?
Trainer’s Signature:

Comment/Feedback:

TITLE Identify and repair faults/troubles
OBJECTIVES
INTRODUCTION In this lesson you will be able to know the safety aspects on
troubleshooting and repairing.

TOPIC 2 Safety practices in performing troubleshooting and repairing

Lesson 1 Safety Aspects

1. PPE is compulsory when handling and working with refrigerants.
2. Always ensure good ventilation while working on refrigeration systems.
3. Ensure that refrigerant cannot accumulate in low areas where they can cause fatal

accidents.
4. Specific color-coding shall be followed for cylinders/containers of different refrigerants.
5. Pressure safety devices (i.e. pressure relief valves, safety pressure switches) shall be

installed to prevent the equipment from operating over the maximum working pressure
and must be calibrated.
6. A dual pressure-relief valve with changeover device shall be installed for larger systems
to facilitate the repair/replacement without impairing system protection.
7. Appropriate safety precautions shall be observed for systems converted with
hydrocarbon.
8. Proper protective caps shall be used on valves of refrigerant cylinders to prevent
damage to valves that will cause refrigerant leaks.
9. Avoid contact with liquid refrigerants that can cause severe frostbite.
10. Hydrochloric and hydrofluoric acids may be present in contaminated recovered
refrigerant and oils. Utmost care must be taken to prevent contact, even with oil spills
when servicing contaminated equipment.
11. Recovered refrigeration oil should be properly stored for proper disposal.
12. Never exceed the cylinder’s safe liquid weight level based on net weight. Maximum
capacity of any cylinder is 80% by maximum gross.
13. Appropriate wheeled device must be used to transport larger cylinders. Ensure that the
cylinder is securely strapped when moving from one location to another. Never roll a
cylinder on its side.
14. Good quality hoses/manifolds should always be used with seals/gaskets in place.
15. Never refill disposable cylinders.
16. Never braze or unbraze refrigeration piping system that has not been fully/properly
evacuated of refrigerant for servicing and filled with inert gas (e.g. dry nitrogen).
17. Never use “halide torch method” (flame test) for leak testing to an unidentified
refrigerant in a system.
18. Never use oxygen or compressed air for pressure or leak testing or when blowing-off
piping to remove welding, brazing or cutting debris.
19. Avoid inhalation or exposure to refrigerant and lubricant vapor or mist. This will irritate
skin, eyes, nose, and throat.
20. Never open refrigerant drums (for low pressure refrigerants) until it is cooled down to
atmospheric pressure/temperature when replacing its cap with valves.
21. Electrical wirings should be kept away from contact with the system’s discharge line.
This will damage the wire’s insulation that may cause short circuit.
22. All power supply should be disconnected and disabled to any equipment from which
refrigerant is being recovered.
23. Never connect grounding wire to gas pipes, water pipes, telephone grounds, and
lightning arresters.
24. Never use refrigerants without first understanding the associated MSDS.

25. Use tools with insulated handles that are in good condition when working with the
system’s electrical lines.

Quiz: TRUE OR FALSE
Direction: Write TRUE if the statement is true and FALSE if the statement is false

1. PPE is compulsory when handling and working with refrigerants.
2. Pressure safety devices (i.e. pressure relief valves, safety pressure switches) shall be

installed to prevent the equipment from operating over the maximum working pressure and
must be calibrated.
3. Proper protective caps shall not be used on valves of refrigerant cylinders to prevent
damage to valves that will cause refrigerant leaks.
4. Never exceed the cylinder’s safe liquid weight level based on net weight. Maximum capacity
of any cylinder is 100% by maximum gross.
5. Always refill disposable cylinders.
6. Never use oxygen or compressed air for pressure or leak testing or when blowing-off piping
to remove welding, brazing or cutting debris
7. Electrical wirings should be kept away from contact with the system’s discharge line.
8. Good quality hoses/manifolds should always be used with seals/gaskets in place.
9. Contact with liquid refrigerants do not cause severe frostbite.
10. Appropriate safety precautions shall be observed for systems converted with hydrocarbon.
Answer Key:

TRUE OR FALSE
1. TRUE
2. TRUE
3. FALSE
4. FALSE
5. FALSE
6. TRUE
7. TRUE
8. TRUE
9. FALSE
10. TRUE

WEB SCRIPT HVAC
Sector:
Qualification: RAC Servicing (DomRAC) NC II
Unit of Competency:
Troubleshoot and Repair Domestic Refrigeration and Air-Conditioning
Module Title: (DomRAC) Systems
Troubleshooting and Repairing Domestic Refrigeration and Air-
Learning Outcomes: Conditioning (DomRAC) Systems
Developer/s: LO3: Perform Refrigerant Recovery/Recycling and Retrofitting/
Conversion on Domestic Refrigeration and Air-Conditioning Unit

Alvin P. Saulon

TITLE Perform refrigerant recovery/recycling and retrofitting/ conversion on
domestic refrigeration
OBJECTIVES In this lesson you will be able to know safety in handling refrigerant
INTRODUCTION
TOPIC 1 Safe handling of refrigerants
Lesson 1 Refrigerants

Refrigerants

A refrigerant is a fluid (liquid and gas) which transfer heat away from one point to another. In a
typical vapor compression system, the refrigerant changes phase. That is, it changes from a liquid
to a gas when it absorbs heat and changes back to a liquid when it gives up heat. Most chemicals
have the ability to change from a liquid to a gas, but only a few chemicals do so in a manner that
makes them good refrigerants.

a visual representation of different types of refrigerant

Most refrigerants used today for vapor compression air conditioning are called Halocarbons
and Hydrocarbons.

Halocarbon (CFC, HCFC, HFC) is a hydrocarbon molecule containing one or more halogens.
The halogen elements most commonly used in refrigerants are chlorine (CI) and fluorine (F).
Refrigerants used in centrifugal chillers are halocarbons based on methane, ethane and propane
molecules.

a visual representation of a CFC refrigerant atom composition
Hydrocarbon (HC) - chemical compounds consisting of one or more carbon atoms surrounded
only by hydrogen atoms. These are not damaging to the ozone layer and have a minimal global-
warming potential. A flammable compound

a visual representation of a HC refrigerant atom composition
Refrigerant Nomenclature—single component refrigerants have an “R-” designation of two
or three numbers, which reflect its chemical composition.
• The first digit (of a refrigerant with three numbers) is one unit lower than the number of

carbon atoms, the first digit is omitted.
• The second digit is one unit greater than the number of hydrogen atoms in molecule.
• The third digit is equal to the number of fluorine atoms in the molecule.

Lesson 2 Safety when handling and working with refrigerants

1. Color-coding for refrigerant cylinders should be maintained for new refrigerants (although
there are concerns from some manufacturers regarding this). Refer to Table 1 for refrigerant
cylinder color assignments.

2. Refrigerant manufacturer’s recommended procedures shall be followed when handling
refrigerants.

3. Refrigerant containers/cylinders shall be stored in a cool place or under a roof to protect it
from weather extremes, away from the risk of fire and direct sunlight.

4. Extra care shall be taken not to drop refrigerant containers/cylinders that may damage the
container or its valve.

5. When not in use, container valves shall be closed, the valve outlet cover nut fitted, and the
valve protection cover replaced.

6. While charging, refrigerant containers/cylinders shall not be connected to a system of higher
pressure to prevent back flow of refrigerant to the container/cylinder.

7. Cylinders intended for a certain type of refrigerant shall not be filled with another type unless
they are properly evacuated and labeled.

8. Strictly follow cylinder capacity when re-filling with refrigerants.
9. When re-filling with recovered refrigerants, only 70% of the maximum capacity in weight for a

particular type of refrigerant should be filled to a cylinder (since it may contain oil with lower
density). Overfilling can cause the cylinder to explode leading to fatal danger.
10. Calibrated weighing scale shall be used when filling a cylinder.
11. Leaks on refrigerant cylinder valves shall be checked and repaired before storing in a
ventilated area and on a vertical position.
12. Establish proper leak testing routine on charging hoses and refrigerant handling equipment.
13. Thorough check-up of refrigerant cylinders shall be done first before refilling.
14. Defective refrigerant cylinders shall not be repaired and re-used.
15. Refrigerant cylinders shall conform to appropriate standards.
16. Storage tank relief valves shall be checked to ensure that they are not leaking (shall conform
to relevant PNS).
17. Transfer pump seals of filling machines shall be regularly checked for leaks.
18. Charging lines shall be kept as short as possible and be fitted with either check valves or
isolation valve near the end of charging lines.
19. Whenever possible, use quick disconnect fittings with one-way valve in transferring or
working with refrigerants.
20. Use PPE, such as side shield glasses/goggles, gloves, jackets, and safety shoes when
handling containers.
21. Never apply direct flame or live steam to a container or valve.

22. Never refill disposable cylinders.
23. Never use a lifting magnet or sling (rope or chain) when handling cylinders.
24. Never use cylinders for rollers, supports, or any purpose other than to contain the refrigerant.
25. Protect cylinders from any object that will result in a cut or other abrasion on the surface of

the metal.
26. Never tamper, repair or alter the safety devices of the cylinders.
27. Never force connections that do not fit.
28. When in doubt of refrigerant type, use electronic refrigerant identifier (will be available in all

Regional EMB offices and TESDA accredited training institutions nationwide) to analyze its
composition.
29. Avoid skin contact with refrigerants as they may cause frostbite and other skin irritations.
30. Blended refrigerants should only be charged into a system in liquid state.

Quiz: TRUE OR FALSE

Direction: Write TRUE if the statement is true and FALSE if the statement is false

1. Color-coding for refrigerant cylinders should be maintained for new refrigerants (although
there are concerns from some manufacturers regarding this). Refer to Table 1 for refrigerant
cylinder color assignments.

2. Refrigerant containers/cylinders shall be stored in a cool place or under a roof to protect it
from weather extremes, away from the risk of fire and direct sunlight.

3. Extra care shall be taken not to drop refrigerant containers/cylinders that may damage the
container or its valve.

4. When not in use, container valves shall be open the valve outlet cover nut fitted, and the
valve protection cover replaced.

5. Strictly follow cylinder capacity when re-filling with refrigerants.
6. When re-filling with recovered refrigerants, only 100% of the maximum capacity in weight for

a particular type of refrigerant should be filled to a cylinder (since it may contain oil with
lower density). Overfilling can cause the cylinder to explode leading to fatal danger.
7. Calibrated weighing scale shall be used when filling a cylinder.
8. Defective refrigerant cylinders can be repaired and re-used.
9. Storage tank relief valves shall be checked to ensure that they are not leaking (shall conform
to relevant PNS).
10. Charging lines shall be kept as long as possible and be fitted with either check valves or
isolation valve near the end of charging lines.
11. Use PPE, such as side shield glasses/goggles, gloves, jackets, and safety shoes when
handling containers.
12. Always apply direct flame or live steam to a container or valve.
13. Never refill disposable cylinders.
14. Never use cylinders for rollers, supports, or any purpose other than to contain the refrigerant.
15. Never tamper, repair or alter the safety devices of the cylinders.

Answer Key:

TRUE OR FALSE

1. TRUE

2. TRUE

3. FALSE

4. FALSE

5. FALSE

6. TRUE

7. TRUE
8. TRUE
9. FALSE
10. TRUE

TITLE Perform refrigerant
recovery/recycling and retrofitting/
OBJECTIVES conversion on domestic
refrigeration
INTRODUCTION In this lesson you will be able to
TOPIC 2 understand the importance of
Lesson 1 recovery of refrigerant and
perform optimum recovery of
refrigerant according to RAC Code
of Practice

Recovery/recycling of
refrigerants
The Ozone issue Montreal and
Kyoto Protocol

The Ozone Issue and The Montreal Protocol

The ozone layer is a thin veil of molecules in the stratosphere, located between troposphere and
ionosphere, which is about 11 - 48 kilometers from the earth’s surface. It blocks most of the
Ultraviolet B or UV-B range from reaching the earth’s surface. Harmful effect of the UV-B rays in
humans include skin cancer, eye disorders, weakening of body’s immune system and damage to
plants and aquatic organisms. The stratospheric ozone depletion became a worldwide issue upon
the discovery of the Antarctic “ozone hole” in 1985. Scientific evidence confirms that ozone
damaged are caused by manmade compounds containing chlorine and bromine-such as
chlorofluorocarbons (CFCs) and halons released in the atmosphere. CFCs were considered as
“miracle compounds” in the chemical industry, but later were identified as the leading cause of
ozone depletion. These are widely used in the industry like refrigeration and air conditioning
(household, commercial, stationary and mobile), foam production (building insulation, flexible and
rigid) and tobacco expansion. This global problem which alerted the international community led to
the adoption of the Montreal Protocol in September 1987 and was entered into force on January 1,
1989 by 73 countries including the Philippines and the EEC. As of 2012, there are197 parties
where South Sudan is the newest member

Kyoto Protocol

The Kyoto Protocol is a pact agreed on by governments at the United Nations conference in
Kyoto, Japan in 1997 to reduce the amount of greenhouse gases emitted by developed countries
by 5.2 percent of 1990 levels during the five-year period 2008-2012. Eighty-four (84) countries
have signed the pact and 40 have already ratified it, with Romania as the only country with
emissions target who have ratified to date. It is the only legally-binding plan for combating global
warming. Greenhouse gases are gases that trap heat in the earth’s atmosphere.

What is NCPP Phase-out Plan?

The Montreal Protocol on substances that deplete the ozone layer is an agreement among
129 countries, including the Philippines that limits the production, application and use of the most
common ozone depleting substances, like CFCs and provides for the phase-out of these
chemicals.

Under the Montreal Protocol, the Philippines is committed to phase out the country’s CFC
consumption by:

National CFC Phase-Out Plan

Year Percentage

2015 10%

2020 35%

2025 67.5%

2030 97.5%

2040 100%

Environmental Laws for Recovery of Refrigerant

Republic Act No. 6969 otherwise known as the “Toxic Substances and Hazardous and Nuclear
Waste Control Act of 1990”. Its main objective is to monitor, regulate and keep an inventory of
imported, manufactured, or used chemicals that presents unreasonable risk or injury to health or
to environment in accordance with the national policies and international commitments.

Republic Act No. 8749, known as the “Clean Air Act of 1999”, RA 8749 is intended to formulate a
holistic national program on air pollution. DENR is the lead agency but cooperates with other
government agencies as well as with industry and related non-governmental organizations. The
Clean Air Act’s primary focus is on ambient air quality but it is applicable to all other pollutants
including ODS

How refrigerants affect ozone layer and global warming

Some refrigerants, especially chlorofluorocarbons (CFCs), contribute to the reduction of the
earth’s ozone layer. The ozone layer is a vital part of the earth’s atmosphere and protects life from
the harmful effects of excessive ultraviolet (UV) radiation, which come from the sun.

1. UV-B radiation -- On land, ultraviolet radiation endangers all living forms. The dangers of
Ultraviolet Radiation are:

• Harmful to human health
• Causes skin cancer
• Causes eye cataracts
• Suppresses man’s immune system

• Arrest the growth of crops and trees
• Practically destroy all life on earth
2. What is Ozone Layer?
Ozone layer is a thin, fragile shield of kind oxygen in the stratosphere. It envelops the entire earth
and blocks off most of the harmful UV rays from the sun from reaching the earth’s surface.

3. What is “0zone hole?”
Ozone hole refers to the loss of the blocking effect of ozone against ultraviolet rays. This is the
consequence when the ozone layer is severely depleted, in effect allowing the entry of greater
concentrations of UV-B imperiling all living things on earth.

a visual representation of ozone hole
4. What is ozone depletion?

Ozone depletion is the loss of the blocking effect of the ozone layer against UV rays from
the sun. The continuous use of ozone depleting substances (ODS) like CFC and halons destroy
the ozone layer.

a visual representation of ozone layer depletion
5. What is Greenhouse Effect and Global Warming— Another environmental effect of refrigerants
is their possible contribution to global warming. The theory of global warming states that, due to
mankind’s activities, the concentration of certain heat-trapping gases is increasing in the
atmosphere. This is believed to be causing the mean temperature of earth’s atmosphere to
increase slowly.

Refrigerants may contribute to global warming by way of a phenomenon called the
greenhouse effect.

a visual representation of greenhouse effect and global warming

Lesson 2 Recovery, Recycling, Reclamation

• Recover: to remove refrigerant in any condition from a system and store an external
equipment in container

• Recycle: to reduce contaminants in used refrigerants by separating oil, removing non-
condensable gases, and using devices such as filter- driers to reduce moisture, acidity and
particulate matter.

• Reclaim: to process used refrigerant to a new product (gas) specifications, and verify by
chemical analysis of the refrigerant that new Training Package HCFC Phase‐out RACSS –
UNEP 2013 product specifications have been met.

Methods of Recovery

• Passive (No external recovery machine used)

❖ Charge migration method
❖ Use of system compressor

Charge Migration Method – Passive
1. Movement of refrigerant due to
natural difference in pressure
between system & recovery cylinder.
2. Process can be speeded up by:

• Evacuating recovery cylinder
• Placing recovery cylinder in ice

bath
3. Only a small percentage of charge
can be recovered

a visual representation of passive method of recovery

• Active

❖ With a recovery machine

a visual representation of active method of recovery

Quiz: MULTIPLE CHOICE: Identify the correct word/s on the following statement. Encircle the
letter of the correct answer.

1. is the loss of the blocking effect of the ozone layer against UV rays from the sun.
A. Ozone layer
B. Ozone hole
C. Ozone depletion
D. Ozone depleting substances

2. Are used in the wide range of household and industrial uses
A. Ozone layer
B. Ozone hole
C. Ozone depletion
D. Ozone depleting substances

3. It is known as the “Clean Air Act of 1999”, it is intended to formulate a holistic national program
on air pollution.
A. Republic Act No. 8749
B. Republic Act No. 8479
C. Republic Act No. 8947
D. Republic Act No. 8497

4. It is otherwise known as the “Toxic Substances and Hazardous and Nuclear Waste Control Act
of 1990”.
A. Republic Act No. 6966
B. Republic Act No. 9696
C. Republic Act No. 6969
D. Republic Act No. 8989

5. It is a pact agreed on by governments at the United Nations conference in Kyoto, Japan in 1997
to reduce the amount of greenhouse gases emitted by developed countries by 5.2 percent of 1990
levels during the five-year period 2008-2012.
A. Koyo Protocol
B. Goto Protocol
C. Kyoto Protocol
D. Montreal Protocol

Job Sheet 1: Recovery of Refrigerant

Performance Given a qualification, you should be able to perform
Objective: optimum recovery of refrigerant
Supplies/Materials: Clean rags, Liquid soap, water, Masking tape, Marker

Equipment: DomRAC unit, Recovery machine w/ accessories,
Steps/Procedure: Gauge manifold, Vacuum pump, Refrigerant weighing
scale, Refrigeration rachet,

I. Standard Liquid/Vapor Recovery Method

1. Make sure the unit is in good operating condition.

Note:
• All connecting port must have cap, if left open perform evacuation procedure.
• If a diff. refrigerant will be recovered perform evacuation.

2. Make sure all connections are correct and tight.
A. Connect blue hose of gauge manifold to low side access valve. (If there is no access valve
installed, a piercing valve must be use.)
B. Connect yellow hose of gauge manifold to inlet of filter drier, connect accessory hose (short
blue hose) to the outlet of filter drier and the other end to IINPUT port of recovery machine.
C. Connect one end of hose to outlet of recovery machine and the other end to recovery tank
(Use an extra hose if needed)
Note: Recovery tank must be vacuum and weigh before sue.

4. Make sure the Recover/Purge valve is set on Recover.

5. Open the output port of the unit.

6. Open the liquid port on your manifold gauge set; opening the liquid port will remove the liquid
from the system first. After the liquid has been removed, open the manifold vapor port to finish
evacuating the system.

a visual representation of recovery of refrigerant hose connection
7. Connect the unit to a right outlet. (See the nameplate on the unit)
Switch the power switch to the ON position and press “Start” to start the compressor.
Note: If the unit fails to start, rotate the Input valve and the Recover/Purge valve to Purge position.
Then rotate the Recover/Purge valve to Recover position, and open the Input valve.

a visual representation of refrigerant recovery machine front panel

8. Slowly open the input port on the unit.
1) If the compressor starts to knock, slowly throttle back the input valve until the
knocking stops.
2) If the input valve was throttled back, it should be fully opened once the liquid has been removed
from the system (the manifold gauge set vapor port should also
be opened at this time).
9. Run until desired vacuum is achieved and the unit shuts down automatically.
1) Close the manifold gauge sets vapor and liquid ports.
2) Close the unit’s input port.
3) Turn off the unit and proceed with the Self-Purge Method on the next page.
CAUTION: Always purge the unit after each use. Failure to purge the remaining refrigerant from
the unit could result in the acidic degradation of internal components, ultimately causing premature
damage.

II. Self-Purging Method
Procedure for purging remaining refrigerant from
this unit
1. Turn INPUT valve to CLOSE; OUTPUT valve to OPEN, and recovery tank valve to OPEN.
2. Turn the Recover/Purge valve to the Purge position.
3. Check the connection hose, and ensure all connections are correct and tight. (Same as
recovery mode)
4. Power on, press “Start” and get started.
5. Turn INPUT valve to “PURGE” slowly, and run this unit until desired vacuum level is achieved
and / or low-pressure protector shuts off automatically.
6. Close the ports on the recovery tank.
7. Turn the Power-off, disconnect all hoses and dry the filter.
8. Turn Self-purging to “RECOVER” position, and both INPUT and OUTPUT valves to “CLOSE”
position.
9. Finally, cover the cap on INPUT and OUTPUT connection adaptor.
10. Leak test recovery tank for leak.

Note: Use electronic leak detector if not available, use soap and bubble solution.
11.Weigh recovery tank, put label and record the recovered refrigerant.

Performance Criteria Checklist

CRITERIA YES NO
1. Does the recovery machine in good condition?
2. Does the hoses connect properly?
3. Does the Recover/Purge valve is set on Recover?
4. Does the output port and liquid port open before switching
on the machine?
5. Does the unit plug into right outlet and switch to on
position?
6. Does the input port on the unit fully opened?
7. Does vacuum achieve and the unit shuts down
automatically?
8. Does the input valve turn to close and put the
recovery/purge to purge position?
9. Does the recovery tank close after purging and leak tested?
10. Does the recovered refrigerant weigh and recorded?

Trainer’s Signature:
Comment/Feedback:

TITLE Perform refrigerant recovery/recycling and retrofitting/ conversion on
OBJECTIVES domestic refrigeration
In this lesson you will be able to understand the importance of
INTRODUCTION recovery of refrigerant and perform optimum recovery of refrigerant
according to RAC Code of Practice
Retrofitting is the process of preparing a refrigeration and air
conditioning system for use with a replacement refrigerant and
lubricant. The basic idea of retrofit is to replace the refrigerant and
refrigerating machine oil.

TOPIC 2 DomRAC systems retrofitting overview
Lesson 1 Basic consideration for retrofitting

Basic Consideration for Retrofitting

• Consider the expected energy efficiency, performance and operating costs of the
retrofitted system in addition to the direct retrofit costs.

• Consider the properties of the alternative refrigerant such as flammability, toxicity and its
global warming potential; some of these properties may require additional safety
measures.

• Consider retrofitting when major damage of the existing system requires expensive
repair work.

• Consult the system manufacturer for the appropriate alternative refrigerant/lubricant
system and the necessary replacement of system components, such as compressor,
filters, drier etc., before retrofitting.

• Consult the system manufacturer for the appropriate retrofitting procedure, which is, in
general, equipment-specific.

• Investigate the operating parameters and performance data of the existing system before
retrofitting.

• Investigate the operating parameters and performance data of the system and control
settings after completion of the retrofit.

• Re-label the retrofitted system and components to reflect the refrigerant and lubricant
change and to indicate future service needs.

• Record the retrofitting procedure in the service logbook.

Note: Observe local regulations concerning the collection, transport, storage and.
destruction of hazardous waste; contact refrigerant suppliers, refrigeration associations
or appropriate government institutions

I. Assess Unit for Retrofit

Retrofitting would appear to be a simple matter since it involves replacing an old refrigerant with a
new one in an existing system. However, because many other factors are involved, it is not generally
a simple process.

Other economic factors must be considered. These factors include:

• The estimated equipment life,
• Current performance,
• Operating requirement, and
• The cost of equipment and equipment room modification, maintenance, refrigerant and

electrical power.

II. Retrofit Factor and Costing

1. The decision to replace or convert existing equipment should be made only after
carefully considering the total costs of both scenarios. To minimize the cost, if timing permits,
it is best to undertake a retrofit operation around a major maintenance period. Many of the
components would normally be replace during a major maintenance overhaul.

Note: Retrofits when compressor has failed and will be replaced is much more cost
effective

2. Many air-conditioning and refrigeration system running on CFC will be retrofitted to
ozone friendly HFCs (i.e.
134a etc.) refrigerants. This will require flushing the mineral oil from the systems and
replacing it with synthetic ester lubricants. To be able to perform such a task the service
contractor needs to be well aware of the retrofit performance and what to consider.

3. Several factors should be considered when approaching a refrigerant retrofit:
• Alternative refrigerant cost.
• Availability of alternative refrigerants in the present and the future.
• Expected life of existing equipment.
• Refrigerant leak history of equipment.

. 4. As a service technician, it is your work to advice equipment owner the best way to
minimized cost, and at the same time maximizes the efficiency of the equipment.
Example on costing is shown below:

No. Measure Unit Cost/Unit Hours Cost/Hour Cost

1 Assessment 1 100 100
No Recovery to change oil -
3 Change oil
1 Recovery to change 3x1L 800 3x2 100 3000

refrigerant 2 100 200
1 New refrigerant
1 New filter 3 kg 300 1 100 1000

1 pc. 500 500

1 Commissioning 1 100 100
Total cost of retrofit 4900

III. Alternative Refrigerants and Lubrication

1. In selecting ozone-compatiblealternatives for CFCs, two molecular concepts are to be
used:
• Eliminate (or at least minimize) C- Cl bonds, and
• Include C-H bonds

This is in addition to maintaining the desirable physical and physiological properties already
ascribed to the CFCs.

2. With these criteria set forth, the major CFCs producers, such as DuPont, Solvay, and ICI,
searched the tables of known fluorocarbons in an attempt to match these properties. From these
tables, which are extensive only a few compounds approximate the physical properties of the
existing CFCs. The following table identifies these compounds:

List of Alternative Refrigerants

Replacement Alternative ODP Main Application
for Refrigerant

R - 11 R - 123 0.02 Water chillers
R - 12
R - 134a 0 Domestic and Commercial
R - 502 Refrigeration (medium
R - 409A 0.05 temperature), fixed and vehicle air-
R - 22 R - 404A 0 con, water chiller
R - 408A
0.026 rCCreeooffrrmmiiggmmeerreeaarrttcciiooiiaannll aanndd ttrraannssppoorrtt
R - 22 0.055 AReirt-rcoofint doiftieoxnisintigng R - 502 systems

R - 407C 0 Stationary air-conditioning

R - 410A 0 Stationary air-conditioning
R - 404A 0

Refrigeration

R - 500 Blends Commercial and Industrial
R - 114 HCFC 124 Chiller application, marine

R - 115 HFC 125 0 Low temperature
0 Domestic/Air-conditioners
R - 12/ R - 22 Hydrocarbons Refrigeration

R - 114 HCFC - 142b

3. The factors that have to be considered in choosing an alternative refrigerant are:
• The refrigerant’s atmospheric lifetime
• The ozone depletion potential (ODP)
• The total equivalent warming index (TEWI) in the intended application
• The refrigerant toxicity and flammability
• The pressure under which the refrigerant operates
• Its heat transfer characteristics
• Its compatibility with materials used in the system
• Miscibility and compatibility with lubricants

IV. Oils for Alternative Refrigerants

1. An important consideration in the development of hydro chlorofluorocarbon (HCFCs) and
hydro fluorocarbons (HFCs) as alternative refrigerants is the testing of oils for solubility,
stability, lubricity with the refrigerant, and compatibility with materials of construction.
Testing will determine which lubricants can be used in current systems and what changes
are required.

2. In general the ternary blends and HCFCs can be used with oils that are commercially
available; however, some development work may be required to optimized performance.
Applications with HFCs require the development of new oils. The desirable properties for
developmental use are:
• Acceptable solubility with the refrigerant (ideally, single phase over a broad
temperature range);
• Acceptable lubricity;
• Good thermal stability for the refrigerant/lubricant combination;
• Acceptable compatibility with system materials (elastomers, metals and plastics);
• Low toxicity; and
• Commercial availability at a reasonable cost.

3. Listed below are the refrigeration lubricating oils and their characteristics:

Mineral Oil (MO)
• Designed for and miscible in CFC/HCFC
• Very soluble in HC (higher viscosity/superheat can be required

Alkylbenzene (AB)
• Designed for and miscible in CFC/HCFC
• Low viscosity AB is also used in rotary compressors for R-407C

Polyol ester oil (POE)