Servicing & Maintaining Window-Type AC and Domestic Ref Units

COMPETENCY BASED LEARNING MATERIAL

Sector:

HEATING, VENTILATING, AIR-CONDITIONING AND REFRIGERATION
(HVAC/R)

Qualification:

RAC Servicing NC II

Unit of Competency:

Service and Maintain Window-Type Air-Conditioning/Domestic
Refrigeration Units

Module Title:

Servicing and Maintaining Window-Type Air-Conditioning/
Domestic Refrigeration Units

Technical Education and Skills Development Authority

East Service Road, South Superhighway, Taguig, Metro Manila

HOW TO USE THIS COMPETENCY-BASED LEARNING MATERIAL

Welcome to the module Service and Maintain Window-Type Air-Conditioning/ Domestic
Refrigeration Units. This module contains training materials and activities for you to complete.

The unit of competency "Servicing and Maintaining Window-Type Air-Conditioning/
Domestic Refrigeration Units" contains knowledge, skills and attitudes required for RAC
Servicing. It is one of the core modules leading to National Certificate level II (NC II).

You are required to go through a series of learning activities to complete each learning
outcome of the module. In each learning outcome are Information Sheets and Instruction
Sheets (Reference Materials for further reading to help you better understand the required
activities). Follow these activities on your own and answer the self-check at the end of each
learning outcome. You may remove a blank answer sheet at the end of each module (or get
one from your facilitator/trainer) to write your answers for each self-check. If you have
questions, don’t hesitate to ask your facilitator/trainer for assistance.

Recognition of Prior Learning (RPL)

You may already have some or most of the knowledge and skills covered in this learner's
guide because you have:

 been working for some time
 already completed training in this area.

If you can demonstrate to your trainer that you are competent in a particular skill or skills,
talk to him/her about having them formally recognized so you don't have to do the same training
again. If you have a qualification or Certificate of Competency from previous trainings, show it to
your trainer. If the skills you acquired are still current and relevant to the units of competencies
they may become part of the evidence you can present for RPL. If you are not sure about the
currency of your skills, discuss this with your trainer.

At the end of this module is a Learner’s Diary. Use this diary to record important dates, jobs
undertaken and other workplace events that will assist you in providing further details to your
trainer or assessor. A Record of Achievement is also provided for your trainer to complete
once you complete the module.

This module was prepared to help you achieve the required competencies on Servicing and
Maintaining Window-Type Air-Conditioning/Domestic Refrigeration Units. This will be the source
of information for you to acquire knowledge and skills in this particular trade independently and
at your own pace, with minimum supervision or help from your instructor.

 Talk to your trainer and agree on how you will both organize the Training for this unit.
Read the module carefully. It is divided into sections, which cover all the skills and
knowledge you need to successfully complete this module.

 Work through all the information and complete the activities in each section. Read the
information sheets and complete the self-check. Suggested references are included to
supplement the materials provided in this module.

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 Most probably, your trainer will also be your supervisor or manager. He/she is there to
support you and show you the correct way to do things.

 Your trainer will tell you about the important things you need to consider when you are
completing activities. It is important that you listen and take notes.

 You will be given plenty of opportunity to ask questions and practice on-the-job. Make
sure you practice your new skills during regular work shifts. This way, you will improve
both your speed and memory and also your confidence.

 Talk to more experienced workmates and ask for their guidance.

 Use the self-check questions at the end of each section to test your own progress.

 When you are ready, ask your trainer to watch you perform the activities outlined in this
module.

 As you work through the activities, ask for written feedback about your progress. Your
trainer keeps feedback/ pre-assessment reports for this reason. When you have
successfully completed each element, ask your trainer to mark on the reports that you
are ready for assessment.

 When you have completed this module (or several modules), and feel confident that you
have had sufficient practice, your trainer will arrange an appointment with registered
assessor to assess you. The results of your assessment will be recorded in your
competency Achievement Record.

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Introduction:

The life span of any refrigeration and air conditioning unit lies on the proper maintenance or
servicing done by refrigeration and air conditioning practitioners. Acquiring the knowledge, skills
and attitude in servicing and maintaining refrigeration and air conditioning unit will make both
the customer and practitioner satisfied with the efficient performance of the unit

Summary of Learning Outcomes:

Upon completion of this module the trainee/student must be able to:

LO 1. Clean and replace air filter.
LO 2. Service evaporator and condenser
LO 3. Maintain fan motor assembly.
LO 4. Service electrical power and controls circuit.
LO 5. Maintain refrigeration system.

Assessment Criteria:

 Identified and classified air filter used in window-type air conditioning units.
 Air filter is checked for damage and replaced if required in line with standard operating

procedures (SOP).
 Air filter is cleaned using appropriate cleaning agent and tool.
 Air filter is replaced in accordance with SOP.
 Proper tools are selected and used in dismantling evaporator and condensing coils.
 High-pressure washer is used in cleaning evaporator/condensing coils.
 Cleaning agent or non-corrosive chemical is used in cleaning evaporator and condensing

coils are checked for brake.
 Fin comb is strengthening coil fins.
 Fan motor is checked in line with standard operating procedures.
 Lubricant is selected according to manufacturer’s specification.
 Fan motor is lubricated with no spillage in line with standard operating procedures.
 Proper electrical tools and test instruments are used in checking power supply and

electrical controls and wiring conditions.
 All electrical controls, wiring power supply are checked and inspected.
 Loose connections are other defects are reported.
 Defective controls and wiring are repaired/replaced in line with standard operating

procedures.
 All parts of refrigerant circuit are checked as per manufacturer’s manual/specifications.
 Refrigerant circuit condition accurately diagnosed and repaired.
 Completion is reported and recorded.
 Followed correct servicing and maintenance procedures.

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Conditions:

The trainee must be provided with the following:

1. Learning Materials
 Module 2 Servicing and Maintaining Window-Type Air-conditioning/Domestic
Refrigeration Units
 Service manual
 Video tapes

2. Training Facilities
 TV monitor
 VHS player

3. Equipment
 Pressure washer
 Air compressor
 Window-type aircon unit
 Ordinary refrigerator unit
 Acetylene equipment

4. Instruments
 VOM
 Clamp ammeter
 Leak detector
 System analyzer
 Thermometer

5. Tools
 Screwdriver
 Allen key wrench
 Adjustable wrench
 Mechanical pliers
 Fin comb

6. Personal Protective Equipment (PPE)
 Apron
 Safety shoes
 Goggles
 Gloves
 Gas mask
 Oil pump

7. Supplies and Materials
 Rags
 Bucket
 Soap
 Air filter
 Lubrication oil

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Prerequisite:

Before commencing this module, you should have read the learning material:
 Good Practice in Servicing RAC System

References:

A. Books
 Modern Refrigeration and Air-conditioning
 Good Practice in Refrigeration Training Manual

B. Curriculum Guides
 HVAC Competency Standard
 HVAC Competency-Based Curriculum

C. Manuals
 Service Manual

Certification Requirement:

To complete this module you must have the competency in using various tools,
equipment, supplies and materials. It is also required that you have the competency in
performing housekeeping and safety practices. If you still lack these competencies, meet
with your trainer/facilitator to determine what method you will use to gain the said skill. One
option is to complete the information and practical activities in the following modules:
 Preparing Materials and Tools;
 Observe Procedures, Specifications and Manuals of Instruction;
 Perform Mensurations and Calculations;
 Maintain Tools and Equipment;
 Perform Housekeeping and Safety Practices; and
 Document Work Accomplished.

Contents of this Competency-Based Learning Material:

Inside this Competency-Based Learning Material are several “Learning Elements”.
Each Learning Element guides the learner to achieve one learning outcome.

In going through each Learning Element, you must follow the “Learning Activity
Sheet”. This Learning Activity Sheet will guide you through different “Instruction Sheets”
that will assist you in performing different learning activities towards the attainment of the
learning outcome.

 Information Sheet - This will provide you with information (concepts, principles
and other relevant information) needed in performing certain
activities.

 Operation Sheet - This will guide you in performing single task, operation or
process in a job.

 Job Sheet - This is designed to guide you on how to do the job that will
contribute to the attainment of the learning outcome.

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 Assignment Sheet - The assignment sheet is a guide used to enhance (follow-up)
what you have learned in the information sheet, operation
sheet or job sheet.

 Worksheet - Worksheets are the different forms that you need to fill-up in
certain activities that you performed.

To utilize the learning material effectively, you also need to familiarize with the different
parts of the sheet.

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Symbols

These symbols are located in the left margin of the module. It illustrates action which
should be taken or resources to be used at the particular stage in this module.

Learning Optional Activity
Outcome

Resources Practice

Reading Activity Self Check

Use Computer Answer Key

View Video Competency
Assessment
Listen to Audio
Tape Safety

Work Sheet

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Reading Activity 1 p 15

Read: Information Sheet 1: Capacitors: Types and Functions in a
Refrigeration System

Practice Activity 1 p 17

Perform: Job Sheet 1: Cleaning Air Filter

Self-Check 1 p 19

Do: Self-Check 1

Reading Activity 2 p 22

Read: Information Sheet 2: Evaporator: Types, Classification
and Location

Reading Activity 3 p 25

Read: Information Sheet 3: Condenser: Types and Classification

Reading Activity 4 p 28

Read: Information Sheet 4: Identifying Cleaning and Rinsing
Solvents

Self-Check 2 p 33

Do: Self-Check 2

Practice Activity 2 p 34

Perform: Job Sheet 2: Cleaning, Removing and/or Replacing
the Evaporator
Self-Check 3
p 44
Do: Self-Check 3

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Practice Activity 3 p 45

Perform: Job Sheet 3: Cleaning a Condenser

Reading Activity 5 p 49

Read: Information Sheet 5: Cleaning and Replacing Fan Motor
and Blade

Practice Activity 4 p 53

Perform: Job Sheet 4: Identifying the Terminal Leads of 3-
Speed Fan Motor Using a Volt-Ohm-
Self-Check 4 Milliammeter (VOM)

Do: Self-Check 4 p 57

Practice Activity 5 p 58

Perform: Job Sheet 5: Cleaning Fan Motor and Fan Blade

Self-Check 5 p 65

Do: Self-Check 5

Practice Activity 6 p 68

Perform: Operation Sheet 1: Checking Electrical Connections

and Controls

Practice Activity 7 p 77

Perform: Operation Sheet 2: Overload Protector: Types, Parts
and Operating Principles in a
Refrigerating System

Self-Check 6 p 80

Do: Self-Check 6

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Reading Activity 6 p 81

Read: Information Sheet 6: Characteristics of Hermetic
Compressor Motor Windings

Self-Check 7 p 83

Do: Self-Check 7

Reading Activity 7 p 84

Read: Information Sheet 7: Electrical Control, Current
and Potential Relays

Self-Check 8 p 91

Do: Self-Check 8

Reading Activity 8 p 94

Read: Information Sheet 8: Capacitors: Types and Functions in a
Refrigerating System

Self-Check 9 p 96

Do: Self-Check 9

Reading Activity 9 p 97

Read: Information Sheet 9: The Thermostat

Self-Check 10 p 104

Do: Self-Check 10

Reading Activity 10 p 106

Read: Information Sheet Types and Operating Principles
10: of a Defrost Timer

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Self-Check 11 p 111

Do: Self-Check 11

Practice Activity 8 p 112

Perform: Operation Sheet 3: Operation of a Semi-Automatic

Defrost Timer

Self-Check 12 p 115

Do: Self-Check 12

Reading Activity 11 p 119

Read: Information Sheet Window-Type Air-Conditioning Cycle
11:

Practice Activity 9 p 120

Perform: Job Sheet 6: Tracing Refrigerant Path Restrictions

Self-Check 13 p 124

Do: Self-Check 13

Practice Activity 10 p 125

Perform: Job Sheet 7: Connecting Domestic Refrigerator,
Frost-Type

Practice Activity 11 p 127

Perform: Job Sheet 8: Connecting Drinking Fountain

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Practice Activity 12 p 130

Perform: Job Sheet 9: Connecting Domestic Refrigerator (No
Frost)

Practice Activity 13 p 132

Perform: Job Sheet 10: Connecting Window-Type Air-
Conditioner

Practice Activity 14 p 135

Perform: Job Sheet 11: Pressurizing and Leak Testing
(Window-Type Air-Conditioner)

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Learning Outcome # 1: Clean and replace air filter

Assessment Criteria:
 Identified and classified air filter used in window-type air conditioning units.
 Air filter is checked for damage and replaced if required in line with standard operating
procedures (SOP).
 Air filter is cleaned using appropriate cleaning agent and tool.
 Air filter is replaced in accordance with SOP.

Resources:

 Refrigeration and air conditioning technology book
 Carrier owner’s manual
 Learning Element

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LEARNING EXPERIENCES

LEARNING OUTCOME NO. 1: Clean and replace air filter

Learning Activities Resources

1. Read information sheet on Identifying /  Ask instructor for identifying/Classifying Air
Classifying Air filters and Proper Filters and Proper Maintenance.
Maintenance.
 Ask instructor for “Identifying/Classifying
2. Answer the Self-Check #1. Air Filters and Proper Maintenance”

3. Perform Activity sheet on “Identifying/  Ask instructor for “Identifying/Classifying
Classifying Air Filters and Proper Air filters and Proper Maintenance”
Maintenance
 Appropriate tools instruments, equipment,
4. Ask instructor if you can proceed to the supplies and materials
next learning outcome.

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INFORMATION SHEET #1

Preventive maintenance, proper service and troubleshooting plays a big part in keeping
humidifying equipment for operating efficiently. Cleaning the components that are in contact
with the water is the most important factor. In evaporative system, these minerals of water
collect on the media, on other moving parts and in the reservoir. In addition, algae, bacteria,
and virus growth can cause problems, even to the extent of blocking the output of the
humidifier. The reservoir should be drained regularly if possible and components, particularly
the media type, should be cleaned periodically.
DIFFERENT TYPES OF AIR FILTERS
1. FIBERGLASS FILTER MEDIA
This media may be purchased in bulk or in frames.
This material is usually an inch thick and coated with
a special non-drying, non-toxic adhesive on each
fiber. A filter material is designed so that it gets
progressively dense as the air passes through it.

Fiberglass filter media purchased in bulk.

Fiberglass filter media purchased in a
frame.

Section of fiberglass media.

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2. EXTENDED SURFACE AIR FILTERS Extended surface air filters.

Some applications do not permit the use of fiberglass
as a filter media or require a higher air velocity than
fiberglass allows. Extended surface filters are after
made of non-woven cotton, producing air-cleaning
efficiencies of up to three (3) times greater than the
fiber glass. This type of filter is often used in computer
and electronic equipment rooms.

3. STEEL WASHABLE AIR FILTERS

These filters are permanent and are washed rather
than replaced. They are usually installed in
commercial applications such as in restaurants,
hotels, and schools.

4. BAG-TYPE AIR FILTERS A steel washable filter.
Bag-type filter
This is another type of filter that produces greater
filtering efficiencies. These filters use fine fiberglass
media within the bags and remove microscopic
particles. These may be used in hospital operating
rooms, electronic equipment assembly rooms and
computer equipment rooms.

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JOB SHEET#1

Cleaning Air Filter

EQUIPMENT:

1. Window-type air conditioning unit
2. Vacuum cleaner
3. Pressure washer

TOOLS:

1. Standard slot-type screwdriver
2. Philips screwdriver
3. Fin comb
4. Paint brush

MATERIALS:

1. Soap (detergent)
2. Rags

PROCEDURE:

1. Disconnect electrical power from window-
type air conditioning unit.

Note: Do not remove the power plug by pulling
by the cord.

2. Remove the front intake grill. Pull up the
front intake grill about 90 and slide it
slightly to the left to unhook the tabs.

CAUTION: Do not raise the front intake grill
higher than 90 to the unit to prevent damage.

3. Remove the air filter. Tilt up and pull out
the air filter by the holder.

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4. Clean the filters using a vacuum cleaner.
Note:
 Turn off the unit and pull out the power
plug.
 Clean the filters once a month.

5. Rinse the filters under running water and
dry them completely. After drying re-fit
them correctly into their guides.

6. Attach the air filter to the front grill.

7. Slide the front intake grill slightly to the
right to reattach the tabs and then push it
down to close tightly.

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SELF-CHECK #1

CALL YOUR INSTRUCTOR who will observe you clean, remove or replace air filter to an air
conditioning unit.

Instructor’s checklist Acceptability
Yes No
1. Selection and preparation of tools and materials to be used. ______ ______
2. Choice of method to be followed. ______ ______
3. Setting up of the workplace, tools, materials and equipment. ______ ______
4. Preparation of the workpiece. ______ ______
5. Thoroughness in cleaning the air filter. ______ ______
6. Speed in completing the job (The job should be completed in 1 ______ ______

hour). ______ ______
7. Observance of safety precautions.

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Learning Outcome #2 : Wash evaporator and condenser coils

Assessment Criteria :

 Proper tools are selected in dismantling evaporator and condensing coils.
 High-pressure washer is used in cleaning evaporator and condensing coils.
 Cleaning agent or non- corrosive chemicals are used in cleaning
 Evaporator and condensing coils are checked for air brake
 Fin comb is used in strengthening coil fins.

Resources:

Equipment and materials

You should be provided with the following:

1. Air conditioning unit
2. Air filter

- Disposable
- Reusable
3. Personal Protective Equipment (PPE)
4. Service manual
5. Basic handtools
- Set of screwdrivers
- Set of wrenches
6. High pressure washer
7. Cleaning agent
- Liquid soap
- Soap powder
8. Forms
- Job order
- Requisition Slip

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LEARNING EXPERIENCES
LEARNING OUTCOME NO. 2: Service Evaporator and Condenser

Learning Activities Resources

1. Read Information Sheet in LE Code RA2-  Learning Element Code
12.3.3 RA2-12.3.3 on
Cleaning/Removing and/or Replacing the
Evaporator/Condenser Coils.

2. Perform Cleaning/Removing and/or  Follow procedure activities
Replacing the evaporator condenser coils. of LE Code RA2-12.3.3
LE title:
Cleaning/Removing and/or Replacing the
Evaporator/Condenser Coils.

3. Answer Self-Check #2 and perform Self-
Check #3.

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LE Code RA2-12.3.3 CLEANING/REMOVING AND/OR REPLACING THE
EVAPORATOR/CONDENSER COILS

INFORMATION SHEET #2

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

Dry or direct expansion evaporator is not actually
“dry” but has a refrigerant control device that admits
only enough liquid refrigerant 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

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 conditions.

Flooded type

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CLASSIFICATION OF EVAPORATOR

STATIC

Cold Plate

Shell

Forced Air

Fin

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EVAPORATOR LOCATION

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INFORMATION SHEET #3

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.

Major types of condensers

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CLASSIFICATION OF CONDENSER

STATIC

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FORCED AIR

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INFORMATION SHEET #4
IDENTIFYING CLEANING AND RINSING SOLVENTS

OBJECTIVES: After completing this Information Sheet, you should be able to:

- identify the various kinds of cleaning and rinsing solvents by getting 100% score in
the self-check.

EQUIPMENT, MATERIALS AND AIDS YOU WILL NEED:

QUANTITY UNIT DESCRIPTION
1 liter Kerosene
1 liter Gasoline
1 piece Wire brush
1 piece Steel brush
Cloth
1 piece Refrigerant container
1 box Soap

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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.

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.

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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.

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).

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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

8. Most of the oil from coated pieces are 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.

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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.

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 #2

CALL YOUR INSTRUCTOR who will guide you and check your work after doing the self-check
below. You have five minutes to finish this test.

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 #2
CLEANING, REMOVING AND/OR REPLACING THE EVAPORATOR

OBJECTIVES: After completing this Job Sheet, you should be able to:

- clean the evaporator heat exchanger surfaces;

- remove and repair an evaporator;

- pressure-wash a finned evaporator; and

- straighten bent fins.

EQUIPMENT, MATERIALS AND AIDS YOU WILL NEED:

QUANTITY UNIT DESCRIPTION
1 piece Sample evaporator available
1 piece Paint brush
1 unit Tube cutter
1 piece Hacksaw
1 pail Soap and water solution
1 Oxy-acetylene
1 set Brazing rod
1 piece Clean rag
1 piece Leak tester
1 piece Sand paper (water proof)
1 piece Steam cleaner
unit

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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
1. Brush off dust or foreign materials with a paint

brush, as shown.

2. Blow compressed air to the evaporators to
remove dust and foreign materials.
Caution: Use a dust mask and goggles to
prevent inhalation of harmful dust and eye injury.

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

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

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

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

7. Test for Leaks. If leak is detected, repair the leaking part by brazing.

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8. 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”.

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

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

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

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12. Braze or weld the leak
NOTE:

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

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

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

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

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PRESSURE WASHING THE FINNED EVAPORATOR

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.

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.

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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) 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.

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.

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

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

STRAIGHTENING BENT FINS
Bent fins may be straightened using a fin comb or wide-nosed pliers, as shown below.
PROCEDURE
1. Insert the wide nose pliers to the bend fins.

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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.

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SELF-CHECK #3

CALL YOUR INSTRUCTOR who will observe you clean, remove or replace an evaporator as
well as straighten the bent fins of an evaporator.

Instructor’s checklist Acceptability
Yes No
1. Selection and preparation of tools to be used ______ ______
2. Choice of method to be followed ______ ______
3. Setting-up of the workplace, tools, and equipment ______ ______
4. Preparation of the workpiece ______ ______
5. Quality of brazed portion or weldments. - Is it leak proof? ______ ______
6. Thoroughness in cleaning finned evaporators ______ ______
7. Quality of repaired bent fins. Is it straight enough after the repair? ______ ______
8. Speed in completing the job. The job should be completed in 2 ______ ______

hours. ______ ______
9. Observance of safety precautions.

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JOB SHEET #3 - CLEANING A CONDENSER

I. Tools and materials
A. Window-type air conditioner
B. Plastic bag
C. Degreasing solvent
D. Water hose
E. Spray nozzle

II. Procedure
1. Remove air conditioner from cabinet.
(CAUTION: Always ask for help when lifting heavy objects.)
2. Set air conditioner close to a floor drain or outside the room
3. Wrap the fan motor with a plastic bag.
(NOTE: Water may ruin the fan motor.)
4. Remove screws that hold the condenser to fan shroud.
5. Carefully swing condenser out (Figure 1)
(CAUTION: Do not swing the condenser out
far enough to avoid kinking or breaking the
refrigerator lines.)
6. Spray degreasing solvent onto condenser.
7. Allow solvent time to work.

Figure 1

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8. Attach water hose to hydrant. Figure 2
(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).

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.
17. Replace air conditioner in cabinet.
18. Clean up and put away tools and materials.

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Learning Outcome # 3 : Maintain Fan Motor Assembly

Assessment Criteria:

 Fan motor is checked in line with standard operating procedures.
 Lubricant is selected according to manufacturer’s specification.

 Fan motor is lubricated without spillage in line with standard operating procedures.

Resources:

EQUIPMENT AND MATERIALS:

You should be provided with following:

1. Air conditioning Unit, window type
2. Lubricant
3. Oil
4. Grease
5. Cleaning agent
6. Rags
7. Soap powder
8. Sand paper

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LEARNING EXPERIENCES

LEARNING OUTCOME NO. 3: Maintain Fan Motor Assembly

Learning Activities Resources
 Information Sheet #5.
1. Read the Information Sheet 5 “Cleaning
and Replacing Fan Motor and Blade.”

2. Do Self-Check #4.  Your instructor will ask you to lubricate the
fan. He will observe your performance
based on the required criteria

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INFORMATION SHEET #5
CLEANING AND REPLACING FAN MOTOR AND BLADE

OBJECTIVE: After completing this Learning Element, you should be able to:
- clean and service a fan motor and fan blade that will function similar to a new unit.

EQUIPMENT, MATERIALS, AND AIDS YOU WILL NEED

QUANTITY UNIT DESCRIPTION
1 unit Fan motor and blade
4 unit blower
4 liters Motor cleaner
1 unit Paint brush 25 mm. wide
1 piece Screwdriver (standard)
1 piece Pliers
1 piece Bearing extractor
1 set Allen key wrenches

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