Troubleshooting Window-Type Air-conditioning / domestic refrigeration systems

5. Observe the deflection of the meter
pointer.

Note: Good – at ON position full
deflection, OFF position no
deflection; Defective –at ON
position, no deflection.

6. Have your instructor check your work.
7. Perform housekeeping.

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Operation Sheet 17

Checking Service Cord/Plug

Objectives: At the end of this practice the learner/trainee will be able to:

o Identify defective service cord/plug using multimeter.
o Follow steps in checking service cord/plug.

Equipment: - 1 unit
o Multi meter - 1 unit
o Refrigeration Unit
- 1 pc
Tools: 1 pc
o Phillips screw driver
o Flat screw driver - 1 pc
o Lineman’s pliers - 1 pc
o Long nose pliers - 1 pc
o Diagonal cutting pliers
- 1 pair
Personal Protective Equipment: - 1 pc
o Gloves
o Goggles

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Procedures:
1. Unplug the unit.

2. Set the multimeter to Rx1 and calibrate
the meter through zero ohm adjust
knob.

3. Place one test prod to one terminal of
the plug and the other test prod to the
end point of the cord.

Note: The cord is good if there is
continuity. It is defective if the
pointer did not deflect.

4. Repeat step number 3 for the other
part of the cord

5. Have your instructor check your work.
6. Perform housekeeping.

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Operation Sheet 18

Continuity Test Air conditioning Unit (Power Cord)

Objectives: At the end of this practice the learner/trainee will be able to:

o Troubleshoot the unit though continuity testing.
o Observe safety practices in troubleshooting the unit.

Equipment: - 1 unit
o Multi meter - 1 unit
o Air conditioning unit

Procedures:

1. Unplug the unit

2. Set the multimeter to Rx1 and calibrate
the zero ohm adjust knob to ensure
accurate reading.

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3. Put the test prod to the power cord.

Note: be sure that the selector
switch of the unit is in off position

4. Switch the unit to the following
position;

Fan position
There must be a definite resistance

reading

Low cool
The resistance reading in this stage

must be lower than the resistance in
FAN POSITION

High cool
The resistance reading in this stage

must be lower than the reading in LOW
COOL

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Off Position
The reading must be infinite

Note: For shorted wiring connection, the
pointer will deflect to zero. For
grounded, set the multimeter to
Rx10,000 and the pointer will indicate a
reading.

5. Have your instructor check your work.

6. Perform housekeeping.

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Information Sheet 12

Oxyacetylene

One of the best methods of making leak proof connections while providing maximum
strength is to braze the joints. These joints are very strong and will stand up under the most
extreme temperature conditions.

Oxyacetylene brazing equipment is used to achieve maximum strength and a leak
proof joint. Oxyacetylene is the introduction of pure oxygen to acetylene. This combined
mixture produce very hot flame.

Correct use of oxyacetylene depends upon the technician constantly metering the flow
of oxygen and acetylene. The oxygen tank and the acetylene tank have pressure regulators
and a set of gauges. One gauge registers tank pressure, the other displays pressure of the
torch.

Acetylene is high flammable gas, especially when mixed with oxygen. Therefore,
safety glasses should always be worn when brazing. Never point the torch (lit and inlet)
towards an open flame or source of sparks. Light the torch only with a sparker- do not use
matches. The acetylene valve adjusts the needed flame size. Slowly turning the oxygen
valve will give required flame. A neutral flame has a blue cone with a bit of reddish purple at
the tip and is most efficient in brazing.

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Parts of oxyacetylene equipment

 Cylinder or tanks- Contains pressurized gases required for any gas welding process.
They are strong metal containers specially designed to safety hold the particular gas
they contain.

o Fuel gas cylinder- this cylinder provides the fuel for the flame. The gas maybe
acetylene (Maroon cylinder) or liquefied petroleum gas (L.P.G.)

o The oxygen cylinder- to achieve a very high flame temperature, it is
necessary to mix pure oxygen with the fuel gas before it is burnt. The color for
the oxygen cylinder is black.

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 Regulators- The function of the
regulator is to break down the high
pressure gas as it leaves the
cylinder so that it can be delivered
through the hoses to hand torch at
a safe manageable pressure

 The welding torch- A welding blow pipe consists of four parts each with their own

individual functions

Control valves: This control the

volume of each gas which is Welding tip
delivered from the regulators to

the welding tip

Hand piece: This is the actual Mixer
handle section of the blowpipe.

Mixer: This mixes the two gases
ready for burning at the welding
tip

Welding tip: This is the actual Hand piece
burner of the blow pipe. It takes Control valve
the mixed fuel gas and oxygen
from the mixer and passes it
through the correct sized hole for
the required flame size. There are
number of different tip sizes
available to given a selection of
flame sizes for welding brazing.

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Operation Sheet 19

Setting-up Oxyacetylene Equipment

Objectives: At the end of this practice, the learner/trainee should be able to:
o Set-up oxyacetylene equipment
o Practice safety precaution in setting-up oxyacetylene

Materials, Tools and Equipment:

Equipment - 1 set
o Oxyacetylene equipment

* - Item is optional
Introduction:

Oxyacetylene equipment is the primary equipment used in performing silver brazing. A
refrigeration and air conditioning technician should be able to handle this equipment properly
to ensure safe working environment and quality work. Setting-up is the first step that needs
to be done for this type of equipment. Below is a setting-up and shutting down procedure for
oxyacetylene equipment.

Procedure:

Before proceeding to activity proper, make sure that you wore the required personal
protective equipment for this task.

1. Crack the cylinder valves to blow any
foreign matter which may damage the
seats or block orifices

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2. Connect regulator to the cylinder and
tighten the nut securely with a wrench

3. Connect the hose assembly to the
regulator and handle

4. Connect the correct size tip to the
handle. Tighten the lock nut finger
tight only

5. Open the tank valve ¼ turn. Use tank
key and leave it on the tank.

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6. Setup the pressure adjusting screw
for the approximate pressure desired

7. Light the flame using flint lighter.
Make sure that the handle tip is not
pointing at flammable object or
person before lighting.

8. Adjust pressure valves to get the
desired flame.

Characteristics of flame

 Neutral flame- burns equal
amount of oxygen and gas is
used in welding steel, stainless
steel, cast iron, copper and
aluminum.

 Oxidizing flame is achieved by
burning an excess amount of
oxygen. The center blue cone
has a distinct point and
achieved by setting a neutral
flame, then reducing the
amount of acetylene. This
flame is used when welding
brass.

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 Carburizing or reducing flame
is obtained by opening the
acetylene further than required
for neutral setting

9. To shut off the torch, close oxygen
valve in the blowpipe then close the
acetylene valve in the blowpipe.

10. Close the tank valve and open the
blowpipe valves to allow the gas to
drain out from the hose

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Operation Sheet 20

Perform Brazing and Soldering

Objectives: At the end of this practice, the learner/trainee should be able to:
o perform brazing and soldering
o apply safety practices in brazing and soldering

Materials, Tools and Equipment:

Materials: - 5 pcs
o Silver rods 1 qrt
o Flux 1 pc
o Wet cloth 1 sheet
o Sand paper 1 pc
o T Copper tubes 3/8 2 mtrs
o Copper tube 3/8
- 1 pc
Tools - 1 pc
o Pliers - 1 pc
o Steel brush
o Mallet - 1 set
- 1 set
Equipment
o Oxyacetylene equipment
o PPE

* - Item is optional

Introduction:

Brazing is the method of joining metals with nonferrous (non-iron) filler using heat
between 800 °F (427 °C) and melting point of base metal.

Soldering is a method of joining two or more metals by adhesion of a metal with a
melting temperature of less than 800 °F (427 °C).

In modern times, most tube and fitting connections are made by either soldering or
brazing. Soldered joints are used for water pipes and drains. Brazed joints are used for
refrigerant pipes and tubing. The difference between soldering and brazing is the
temperature at which solder flows.

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Solder joints used capillary action to draw molten solder into the area between fittings
and the tube. The selection of solder is based upon two factors: operating pressure and
temperature of the line. A 50/50 tin-lead solder is appropriate for moderate pressure and
temperature. It is a mixture of one-half tin and one half lead. It melts at 360°F (182 °C) and is
fluid at 415 °F (213 °C). For higher pressure or greater joint strength, 95/5 tin-antimony
solder is used. This mixture contains 95% tin and 5% antimony and is harder than 50/50
solder. A 95/5 solder melts at 450 °F and is fully liquid at 465 °F (241 °C).

In brazing, brazing filler metals are used to produce a stronger bond. They also have
the advantage of joining similar and dissimilar metals at low hazing temperature. Brazing
filler metals melt at temperature in range of 1000 °F (583 °C) and 1500 °F (816 °C). Brazing
filler metals used for joining copper tubing are of two categories; alloys containing 30-60%
silver, and copper alloys which contain phosphorus. These two classes vary in melting,
flowing and fluxing characteristics. Strength of brazed copper joint is not as dependent upon
choice of filler metals but depends upon proper clearance between the tube and the socket
of the fitting.

Recommended step by step procedure to follow soldering tubing
Procedure:

1. Cut the tube to length and remove
burr with file or scrape

2. Clean outside of tube with clean
sandpaper or sand cloth

3. Clean inside of fitting with a clean
wire brush, sand paper or sand cloth.
Do not use emery cloth

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4. Apply flux thoroughly to outside of
tube then assemble tube and fitting

5. Apply heat with torch. When solder
melts upon contact with heated
fitting, the proper temperature for
soldering has been reached.
Remove flame and feed solder to the
joint at one or two points until a ring
of solder appears at the end of the
fitting.

6. Tap larger sized fitting with mallet
while soldering, to break surface
tension and to distribute solder
evenly in joint

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Assignment Sheet 2

Soldering and Brazing Tube Fittings

Objectives: At the end of this practice, the learner/trainee should be able to:
o perform brazing and soldering
o apply safety practices in brazing and soldering

2. After learning how to solder or braze tube fittings, you will perform soldering and
brazing on your own.

3. The purpose of this activity is to enhance your knowledge and skill in soldering and
brazing of tube fittings.

4. Your tasks are;

o Ask your trainer about common fittings which maybe soldered or brazed to
tubing.

o Based on the step by step procedures in soldering and brazing, solder/brazed
tube fittings

o After completion, let your trainer check your work.

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Information Sheet 13

Evaporator

The Evaporator is the part of the low-pressure side of the refrigeration and air
conditioning system in which the low-pressure liquid refrigerant boils and evaporates. Here
the liquid refrigerant picks-up (absorbs) heat from a cooling medium and changes it into gas
(evaporation). The evaporator is commonly called freezer coil, cooling coil, or chiller.

Two Main Types of Evaporator

1. Dry or direct expansion type
2. Flooded type

1. Dry or direct expansion evaporator
is not actually “dry” but has a
refrigerant control device that admits
only enough liquid refrigerants to be
completely evaporated by the time it
reaches the outlet of the coil. All the
refrigerants leave the coil in a dry state
or dry vapor. The feed for such
evaporator may be either at the top or
the bottom.

Direct or dry expansion evaporator

2. Flooded evaporator recirculates the
refrigerant by using surge chamber or
accumulator. The surge chamber is a
drum in which liquid enters from
metering device. The whole surface of
the evaporator coil is in contact with
the liquid refrigerant under all load
condition.

Flooded type

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STATIC

Cold Plate

Fin Shell

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EVAPORATOR LOCATION

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Information Sheet 14

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.

TYPES OF CONDENSER

There are three types of condensers. The name of each type is determined by the
condensing medium. An air-cooled condenser uses air as the condensing medium; a water-
cooled condenser, water and the evaporative condenser both air and water.

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CLASSIFICATION OF CONDENSER

STATIC

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FORCED AIR

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Information Sheet 15
Identifying Cleaning and Rinsing Solvents

INTRODUCTION
A good cleaning material for refrigeration systems should be able to remove oil, grease and
sludge. The cleaning method to be followed must remove moisture and not injure the parts of
the unit or harm the user.

1. Cleaning and rinsing solvents come in
various kinds depending on the parts
to be cleaned or rinsed. The most
common ones are soap and water,
kerosene, gasoline and carbon
tetrachloride.

2. The refrigerator body and the
compressor housing may be cleaned
by scrubbing the surface using brush
and washing it with water.

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3. Plastic parts should be cleaned gently
with soft bristles or cloth. Use water
mixed with a few milliliters of vinegar.

NOTE: Do not use gasoline or thinner in
cleaning plastics.

4. Soiled parts can easily be cleaned
using kerosene and rubbing the dirt off
with a brush. Corroded metal parts
may be cleaned using a rust converter
and a steel brush.

5. The inside of a compressor can easily
be cleaned using gasoline or
kerosene.

NOTE: When using gasoline, keep away
from open flame or sparks to avoid
explosion. Gasoline is highly flammable.

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6. Evaporators and capillary tubes are
cleaned by using liquid carbon
tetrachloride. This may be bought from
local drugstores.

WARNING:

The American Standards Association
cautions that constant contact of this
substance with the skin may be toxic to
the user. (The threshold limit for carbon
tetrachloride is placed at 10 parts per
million at an eight-hour exposure time).

NOTE:

Carbon tetrachloride however, should
never be used in cleaning the refrigerator
or air-conditioning mechanism because it
is toxic and harmful to the skin and
respiratory system.

7. Most servicing centers recommend the
use of R-123 for flushing the system
contaminated by motor burn-outs
because it is non-toxic and non-
flammable. It does not also leave non-
condensable residues and has no
reaction to electrical insulation.

Container with R 123 Dichlorotrifluoroethane

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8. Most of the oil from coated pieces is
removed by using solvents. They are
immersed into the solvent usually
mineral spirits placed in hooded and
vented containers.

9. To remove grease or lubricants made
from animal or vegetable oils, soak the
piece in alkaline solution so that the oil
will react with the alkali to form water
soluble soap compounds. This
process is called saponification.

10. If minerals cannot be removed by
saponification process, you may try
the emulsification process - the
process by which solid are melted by
mixing them with liquids.

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11. The steam cleaning method may also
be tried. This is done by exposing the
piece to hot water or steam so that the
grease will turn into fluid and float to
the surface. Extra care should,
however, be taken so that the service
technician will not suffer from burns.

12. Caustic solution cleaning is done by
dissolving caustic solution in hot water
and rubbing the piece with the hot
solution to remove grease and oil.

13. Nowadays, there are several cleaning

fluids available in the market. When

using them read and follow the
manufacturer’s recommendations

carefully.

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Self-Check 10
Identifying Cleaning and Rinsing Solvents

MATCHING TYPE:

Direction: Match column A with column B. Write the letter before each number.

Column A Column B

______ 1. Caustic solution cleaning a. carbon tetrachloride

______ 2. Steam cleaning b. for cleaning soiled pieces

______ 3. Solvent cleaning c. dissolving solids by mixing with
______ 4. Saponification liquids

d. soaking into alkaline solution

______ 5. Emulsification e. for flushing contaminated systems

______ 6. For cleaning evaporators and capillary f. for cleaning plastics
tubes g. for cleaning body of refrigerator

______ 7. Refrigerant 11

______ 8. Water with vinegar h. for cleaning inside of compressor

______ 9. Kerosene i. for removing oil from coated pieces
______ 10. Water by immersion

j. removing grease and oil by
immersion in hot solution

k. exposing part to hot water or
steam to remove dirt

l. for cleaning body of refrigerator or
compressor

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Job Sheet 6
Cleaning, Removing and/or Replacing the Evaporator

Objectives: At the end of this practice the learner/trainee will be able to:

o Clean evaporator and heat exchanger surfaces
o Remove and repair evaporator
o Pressure wash a finned evaporator
o Straighten bent fins.
o Observe safety precautions in testing capacitor.

Equipment: - 1 unit
o Oxy-acetylene - 1 unit
o Leak tester - 1 unit
o Steam cleaner
- 1 pc
Materials: - 1 pc
o Soap and water solution - 1 pc
o Brazing rod - 1 pc
o Sand paper (water proof)
o Clean rag - 1 pc
- 1 pc
Tools: - 1 pc
o Paint brush
o Tube cutter - 1 pair
o Hacksaw - 1 pc

Personal Protective Equipment:
o Gloves
o Goggles

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INTRODUCTION

The inside and outside surfaces of the evaporator must be kept clean for good heat
transfer. Air or water being cooled must flow in and out of the evaporator efficiently. See
illustration below.

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CLEANING THE EVAPORATOR SURFACES
Procedures:

6. Brush off dust or foreign materials
with a paint brush, as shown.

7. Blow compressed air to the
evaporators to remove dust and
foreign materials.

8. Isolate the parts to be opened from
the rest of the system.

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9. Using soap and water clean and dry
the joints to be opened.

10. As soon as the ends of the evaporator
tubing are opened, plug the openings
using wood or cork.

11. Polish the weld or clean the brazed
joint with sand paper.

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12. Test for Leaks. If leak is detected,
repeat brazing again.

13. For aluminum evaporators, repair with
an aluminum solder, aluminum braze,
aluminum weld or a special epoxy.
- Locate the leak.
- If necessary, refer to the L.E. on
“Leak Testing”.

14. Recover the refrigerant. If necessary,
refer to the L.E. on “Evacuating or
Flushing the System”.

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15. Clean the metal around the leak with
a cloth or brush.

16. Using a file/sandpaper, remove the
hard surface oxide.

17. Braze or weld the leak

NOTE: If necessary, refer to the
Learning Element on “Soldering and
Brazing”

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18. Polish the weld or clean the brazed
joints using sandpaper.

19. Test for leaks. If a leak is detected,
repeat brazing again.

20. Polish the weld or clean the brazed
joints using sandpaper.

21. Have your instructor check your work.
22. Perform housekeeping.

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Job Sheet 7

Pressure Washing Finned Evaporator

Objectives : When you have completed this job sheet, you will be able to:
 Clean finned evaporator using pressure washer
 Straighten bent fins
 Observe safety practices in cleaning finned evaporator using
pressure washer.

Equipment: - 1 unit
o Pressure Washer
-
Materials:
o Cleaning agents - 1 pc

Tools: - 1 pair
o Long nose pliers - 1 pc

Personal Protective Equipment:
o Gloves
o Goggles

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Procedures:

1. Dirt insulates the condenser, thus hampers
the heat transfer. The fins and coil of the
condenser must be clean so that the
airflow through the coils will not be
insulated from the fin or plate area and
there will be efficient transfer of heat.

- The finned condenser can be cleaned by
compressed air, nitrogen or carbon
dioxide. See figure below for equipment
to be used.

2. Set the pressure regulator of the
compressed air, nitrogen or carbon dioxide
at 6.90 kg/cm by turning the pressure
regulator valve handle clockwise, as shown
by the arrow in the picture.

3. Slowly work the spray up and down the
fins.

4. Direct the spray nozzle so that it is parallel
to the fins. Do not spray at an angle to the
fins because they could be bent and may
cause damage to the coil.

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5. Bring the spray nozzle up in a vertical
angle with the fins and then cross about
2.54 cm. Bring the nozzle down and repeat
the up and down movement of the spray.

6. Keep repeating the spraying pattern until
the entire coil is covered.

7. If the compressed air, soap and water
spray fail to thoroughly clean the
evaporator, a portable steam cleaner may
be used. (See figure below.) The steam jet
should be sprayed with the same technique
as the compressed gas and soap and
water cleaning. The fins may be bent
slightly but they can be easily straightened
with wide-nosed pliers.

STEPS IN USING PORTABLE STEAM
CLEANER

1. Open gate valve of water source by turning
counter-clockwise, as shown.

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2. Plug-in steam cleaner to run motor and
pump, as shown.

3. Position evaporator to be cleaned by
putting on top of 2 wooden blocks, as
shown.

4. Point the nozzle of the steam to the
evaporator and press the switch to bring
out the steam, as shown.

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5. Slowly move the nozzle upward and
downward moving sideways to other fins
until all the evaporator area is cleaned.

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Job Sheet 8

Straightening Bent Fins

Objectives : When you have completed this job sheet, you will be able to:
 Straighten bent fins
 Observe safety practices in straightening bent fins.

Equipment: 1 pc
o Evaporator
- 1 pc
Tools: - 1 pc
o Long nose pliers
o Fin comb - 1 pair
- 1 pc
Personal Protective Equipment:
o Gloves
o Goggles

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Procedure:
1. Insert the wide nose pliers to the bend fins.

2. Press the wide nose pliers slightly until you
see that bends are already straight.

3. Repeat steps one and two until bent fins are
straightened.

4. Have your instructor check your work
5. Perform housekeeping.

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Job Sheet 9

Cleaning Condenser

Objectives : When you have completed this job sheet, you will be able to:
 Straighten bent fins
 Observe safety practices in straightening bent fins.

Equipment: - 1 pc
o Condenser - 1 unit
o Pressure washer
- 1 pc
Materials: - 1 pc
o Cleaning agents - 1 pc
o Degreasing Solvent
- 1 pair
Tools: - 1 pc
o Long nose pliers
o Pail
o Fin comb
o

Personal Protective Equipment:
o Gloves
o Goggles

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Procedures: Figure 1

1. Remove air conditioner from the cabinet

Caution: Always ask for assistance when
lifting heavy objects

2. Set air conditioner close to the floor drain or
outside the room

3. Wrap the fan motor with plastic bag to avoid
water from getting inside the motor.

4. Remove the screws that hold the condenser
fan shroud.

5. Carefully swing the condenser out.
6. Spray degreasing solvent onto condenser.
7. Allow solvent time to work.

(CAUTION: Do not swing the condenser out
far enough to avoid kinking or breaking the
refrigerator lines.)
8. Attach water hose to hydrant.

(NOTE: If using hot water, be sure the hose is
designed for use with hot water.)
9. Attach spray nozzle to water hose.
10. Spray condenser with water (Figure 2).

Figure 2

11. Tilt air conditioner sideways so that water will
run out.

12. Remove plastic bag from fan motor.
13. Dry all electrical components with a shop

towel.
14. Carefully move condenser back into proper

position.
15. Replace screws which hold the condenser to

the shroud.
16. Have instructor check your work
17. Replace air conditioner in cabinet.
18. Perform housekeeping

Code No. Troubleshooting Window Type Air- Date: Developed Date: Revised Page #

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Job Sheet 10

Determining Defective Compressor (Stuck-up and
Loss Compression)

Objectives : When you have completed this job sheet, you will be able to:
 Determine the condition of the motor
 Identify defective compressor through pressure data.
 Follow steps in determining stuck-up compressor motor
 Observe safety practices in determining defective compressor.

Equipment: - I unit
o Refrigeration/Window type ACU - I unit
o Recovery/Recycling machine - I unit
o System analyzer - I unit
o Oxy-acetylene
- 1 pc
Materials: - 1 pc
o Rags - 1 pc
o Sand paper
o Masking tape - 1 pc
- 1 pc
Tools: - 1 pc
o Extension Cord - 1 pc
o Philips screw driver - 1 pc
o Flat screw driver
o Long nose pliers - 1 pair
o Adjustable wrench - 1 pc
o Ammeter - 1 pc

Personal Protective Equipment:
o Gloves
o Goggles
o Safety shoes

Procedures:

1. Prepare all the necessary tools,
materials and equipment

2. Wear PPE
3. Recover/recycle refrigerant if

necessary.
4. Disconnect compressor motor from the

unit

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conditioning/Domestic Refrigeration System 195 of 287

5. Install process tube on both suction
and discharge lines.

6. Test and run the compressor for at
least 5 seconds.

7. Record data on discharge pressure
and amperage reading. The ampere
reading is below full ampere if the
motor is loss compression.

8. If the discharge pressure is less than
100 psig, the motor compressor is
defective (loss compression).

9. If the motor produces humming sounds
with high amperage reading and
probably the overload protector trips.
The compressor may be stuck-up.

10. Replace compressor.
11. Have your instructor check your work.
12. Perform housekeeping

Code No. Troubleshooting Window Type Air- Date: Developed Date: Revised Page #

conditioning/Domestic Refrigeration System 196 of 287

Job Sheet 11

Determining Leaky Refrigeration/Air conditioning
System

Objectives : When you have completed this job sheet, you will be able to:
 Find leaky part of the system
 Repair leak.
 Observe safety practices in determining defective compressor.

Equipment: - I unit
o Refrigeration/Window type ACU - I unit
o Recovery/Recycling machine - I unit
o System analyzer - I unit
o Oxy-acetylene - I unit
o Leak detector
- 1 pc
Materials: - 1 pc
o Rags - 1 pc
o Sand paper
o Masking tape - 1 pc
- 1 pc
Tools: - 1 pc
o Extension Cord - 1 pc
o Philips screw driver - 1 pc
o Flat screw driver
o Long nose pliers - 1 pair
o Adjustable wrench - 1 pc
o Ammeter - 1 pc

Personal Protective Equipment:
o Gloves
o Goggles
o Safety shoes

Procedures:

1. Prepare all the necessary tools,
materials and equipment

2. Wear PPE
3. Install system analyzer
4. Inject 150 psig nitrogen into the

system

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conditioning/Domestic Refrigeration System 197 of 287

5. Observe system analyzer, evaporator
coil, condenser coil and other piping.

6. If the low side pressure continues to
decrease, apply soap suds or use leak
detector to parts with suspected leaks.

7. Leaky system has less full ampere.

8. If leak found, rectify.
9. If the leak found cannot be repaired,

replace it with new one. (Example;
evaporator, piping lines, condenser
coil, metering device)
10. Service the system, then observe its
performance.
11. Have your instructor check your work.
12. Perform housekeeping

Code No. Troubleshooting Window Type Air- Date: Developed Date: Revised Page #

conditioning/Domestic Refrigeration System 198 of 287

Job Sheet 12

Determining Clogged Refrigeration/Air conditioning
System

Objectives : When you have completed this job sheet, you will be able to:
 Troubleshoot clogged accessories.
 Repair/Replace clogged accessories
 Observe safety practices in repairing clogged accessories.

Equipment: - I unit
o Refrigeration/Window type ACU - I unit
o Recovery/Recycling machine - I unit
o System analyzer - I unit
o Oxy-acetylene - I unit
o Leak detector
- 1 pc
Materials: - 1 pc
o Rags - 1 pc
o Sand paper
o Masking tape - 1 pc
- 1 pc
Tools: - 1 pc
o Extension Cord - 1 pc
o Philips screw driver - 1 pc
o Flat screw driver
o Long nose pliers - 1 pair
o Adjustable wrench - 1 pc
o Ammeter - 1 pc

Personal Protective Equipment:
o Gloves
o Goggles
o Safety shoes

Procedures:

1. Prepare all the necessary tools,

materials and equipment

2. Wear PPE

3. Tests run the unit.

4. Check for kinks in metering device.

5. Check for any frosting portion on the

inlet of the evaporator.

6. Check for sweating, frosting or cold

filter drier., filter drier should be warm

during normal operation

Code No. Troubleshooting Window Type Air- Date: Developed Date: Revised Page #

conditioning/Domestic Refrigeration System 199 of 287