Friedrich 2007 User Manual

Service Manual

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2007

Room Air Conditioners

RAC-Svc-07 (4-07)

TABLE OF CONTENTS

Introduction / Typical Unit Components .......................................................................................................................................3

Warranty ....................................................................................................................................................................................... 4

Routine Maintenance ........................................................................................................... ........................................................5

Unit Identiﬁ cation / Nomenclature ................................................................................................................................................ 6

Performance Data .........................................................................................................................................................................7

Electrical Data ..............................................................................................................................................................................8

Functional Component Deﬁ nitions ..............................................................................................................................................9

Electronic Controls ..................................................................................................................................................................9-10

Refrigeration Sequence of Operation .........................................................................................................................................11

Sealed Refrigeration Repairs .................................................................................................................................................11 -12

Refrigerant Charging .............................................................................................................................................................13-1 5

T roubleshooting .....................................................................................................................................................................16-23

Wiring Diagrams ....................................................................................................................................................................24-35

The information contained in t his manual is intended for use by a qualiﬁ ed ser vice technician who is familiar

with the safety procedures required i n in stal la tion a nd repair, and who is equipped with the proper tools and test instruments.

Installation or repairs made by unqualiﬁ ed persons can result in hazards subjecting the unqualiﬁ ed person making such repai rs to the risk of injury or electrical shock which can be serious or even fatal not only to them, but also to persons being served by the equipment.

If you install or perform service on equipment, you must assume responsibilit y for any bodily injur y or property damage which may result to you or others. Friedrich Air Conditioning Co mpany will not be responsible for any injury or property damage arising from improper installation, service, and/or service procedures.

INTRODUCTION

This service manual is designed to be used in conjunction with the installation manuals provided with each air conditioning

system component.

This servic e manual was writ ten to as sist the profes sional R AC ser v ice tec hnician to quick ly and ac curately diagnose and

repair malfunctions.

This manual will deal with subjects in a general nature. (i.e. all text will not pertain to all models).

TYPICAL UNIT COMPONENTS

Capillary Tube

Reversing Valve

(some models)

Front Cover

System Switches

Evaporator Coil

Return Air Grille/Filter

Blower Wheel

Blower Motor

IMPORTANT: diagnosis and repair (See Unit Identiﬁ catio n).

It will be necessary for you to accurately identify the unit you are servicing, so you can be certain of a proper

Fresh Air

Compressor

Liquid Filter Driers

Condenser Coil

Discharge Air

Outdoor Grille

Sleeve

Condenser Fan Blade

Basepan

Friedrich Air Conditioning Company

P.O. Box 1540

San Antonio, TX 78295

210.357.4400

www.friedrich.com

ROOM AIR CONDITIONERS

LIMITED WARRANTY

FIRST YEAR

ANY PART: If any part supplied by FRIEDRICH fails because of a defect in workmanship or material within twelve months from

date of original purchase, FRIEDRICH will repair the product at no charge, provided room air conditioner is reasonably accessible for service. Any additional labor cost for removing inaccessible units and/or charges for mileage related to travel by a Service Agency that exceeds 25 miles one way will be the responsibility of the owner. This remedy is expressly agreed to be the exclusive remedy within twelve months from the date of the original purchase.

SECOND THROUGH FIFTH YEAR

SEALED REFRIGERANT SYSTEM: If the Sealed Refrigeration System (defined for this purpose as the compressor, condenser

coil, evaporator coil, reversing valve, check valve, capillary, filter drier, and all interconnecting tubing) supplied by FRIEDRICH in your Room Air Conditioner fails because of a defect in workmanship or material within sixty months from date of purchase, FRIEDRICH will pay a labor allowance and parts necessary to repair the Sealed Refrigeration System; PROVIDED FRIEDRICH will not pay the cost of diagnosis of the problem, removal, freight charges, and transportation of the air conditioner to and from the Service Agency, and the reinstallation charges associated with repair of the Sealed Refrigeration System. All such cost will be the sole responsibility of the owner. This remedy is expressly agreed to be the exclusive remedy within sixty months from the date of the original purchase.

APPLICABILITY AND LIMITATIONS: This warranty is applicable only to units retained within the Fifty States of the U.S.A., District of Columbia, and Canada. This warranty is not applicable to:

1. Air filters or fuses.

2. Products on which the model and serial numbers have been removed.

3. Products which have defects or damage which results from improper installation, wiring, electrical current

OBTAINING WARRANTY PERFORMANCE: Service will be provided by the FRIEDRICH Authorized Dealer or Service Organization in your area. They are listed in the Yellow Pages. If assistance is required in obtaining warranty performance, write

to: Room Air Conditioner Service Manager, Friedrich Air Conditioning Co., P.O. Box 1540, San Antonio, TX 78295-1540.

LIMITATIONS: THIS WARRANTY IS GIVEN IN LIEU OF ALL OTHER WARRANTIES. Anything in the warranty notwithstanding, ANY IMPLIED WARRANTIES OF FITNESS FOR PARTICULAR PURPOSE AND/OR MERCHANTABILITY SHALL BE LIMITED TO THE DURATION OF THIS EXPRESS WARRANTY. MANUFACTURER EXPRESSLY DISCLAIMS AND EXCLUDES ANY LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGE FOR BREACH OF ANY EXPRESSED OR IMPLIED WARRANTY.

NOTE: Some states do not allow limitations on how long an implied warranty lasts, or do not allow the limitation or exclusion of

consequential or incidental damages, so the foregoing exclusions and limitations may not apply to you.

OTHER: This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.

PROOF OF PURCHASE: Owner must provide proof of purchase in order to receive any warranty related services.

All service calls for explaining the operation of this product will be the sole responsibility of the consumer.

All warranty service must be provided by an Authorized FRIEDRICH Service Agency, unless authorized by FRIEDRICH prior to repairs being made.

characteristics, or maintenance; or caused by accident, misuse or abuse, fire, flood, alterations and/or misapplication of the product and/or units installed in a corrosive atmosphere, default or delay in performance caused by war, government restrictions or restraints, strikes, material shortages beyond the control of FRIEDRICH, or acts of God.

(10-04)

ROUTINE MAINTENANCE

NOTE: Un its are to be inspected and serviced by qualiﬁ ed service personnel only.

Routine maintenance is required annually or semi-annually, depending upon annual usage.

1. Clean the unit air intake ﬁ lter at least every 250 to 300 fan hours of operation or when the unit’s indicator light is on if so equipped. Clean the ﬁ lters with a mild detergent in warm water and allow to dry thoroughly before reinstalling.

2. The indoor coil (evaporator coil), the outdoor coil ( condenser coil) and base pan should be inspected periodically (yearly or bi-yearly) and cleaned of all debris (lint, dirt, leaves, paper , et c.). Clean the coils and base pan with a soft brush and compressed air or vacuum. If using a pressure washer, be careful not to bend the aluminium ﬁ n pack. Use a sweeping up and down motion in the direction of the vertical aluminum ﬁ n pack when pressure cleaning coils. Cover all electrical components to protect them from water or spray. Allow the unit to dry thoroughly before reinstalling it in the sleeve.

NOTE: Do not use a caustic coil cleaning agent on coils or base pan. Use a biodegradable cleaning agent and degreaser.

Inspect the indoor blower housing, evaporator blade, condenser fan blade, and condenser shroud periodically (yearly or

bi-yearly) and clean of all debris (lint, dirt, mold, fungus, etc.) Clean the blower housing area and blower wheel with an antibacterial / antifungal cleaner. Use a biodegradable cleaning agent and degreaser on condenser fan and condenser shroud. Use warm or cold water when rinsing these items. Allow all items to dry thoroughly before reinstalling them.

3. Periodically (at least yearly or bi-yearly): inspect all control components, both electrical and mechanical, as well as the power supply. Use proper testing instruments (voltmet er, ohmmeter , ammeter , wattmeter, etc. ) to perform electrical tests. Use an air conditioning or refrigeration therm ometer to check room, outdoor and c oil operating temperatures. Use a sling psychrometer to measure wet bulb temperatures indoors and outdoors.

4. Inspect the surrounding area (inside and outside) to ensure that the units’ clearances have not been compromised or altered.

5. Inspect the sleeve and drain system periodically (at least yearly or bi-year ly) and clean of all obstructions and debr is. Clean both areas with an antibacterial and antifungal cleaner. Rinse both items thoroughly with water and ensure that the drain outlets are operating correctly. Check the sealant around the sleeve and reseal areas as needed.

6. Clean the front cover when needed. Use a mild detergent. Wash and rinse with warm water. Allow it to dry thoroughly before reinstalling it in the chassis.

UNIT IDENTIFICATION

Model Number Code

S S 08 L 1 0 A

1st Digit – Function

S = Straight Cool, Value Series Y = Heat Pump E = Electric Heat K = Straight Cool R = Straight Cool X = Straight Cool W = Thru-the Wall,

WallMaster Series

2nd Digit

C = Casement Q = Q-Star S = Small Chassis M = Medium Chassis L = Large Chassis H = HazardGard

3rd and 4th Digit - Approximate BTU/HR (Cooling)

Heating BTU/Hr capacity listed in the Speciﬁ cation/Performance Data Section

8th Digit – Engineering

Major change

7th Digit – Options

0 = Straight Cool & Heat Pump Models

1 = 1 KW Heat Strip, Normal 3 = 3 KW Heat Strip, Normal 4 = 4 KW Heat Strip, Normal 5 = 5 KW Heat Strip, Normal

6th Digit – Voltage

1 = 115 Volts 3 = 230-208 Volts

5th Digit

Alphabetical Modiﬁ er

RAC Serial Number Identiﬁ cation Guide

Serial Number Decade Manufactured

L=0 C=3 F=6 J=9 A=1 D=4 G=7 B=2 E=5 H=8

Year Manufactured

A=1 D=4 G=7 K=0 B=2 E=5 H=8 C=3 F=6 J=9

Month Manufactured

A=Jan D=Apr G=Jul K=Oct B=Feb E=May H=Aug L=Nov C=Mar F=Jun J=Sept M=Dec

L C G R 00001

Production Run Number

Product Line

R = RAC P = PTAC E = EAC V = VPAK H = Split

PERFORMANCE DATA

FUSE

Amps

60 Hertz

BREAKER

Voltage

R-22

REF.

in OZ.

Charge

Locked

Rotor Amps

Heat

Amps

ELECTRICAL RATINGS

Cool

Amps

OPERATING

PRESSURES

Sub-

Cooling

Heat

Super

Temp

Suction

Temp

Discharge

DEG. F

CONDENSER

TEMPERATURE

Temp.

Discharge

EVAP. AIR TEMP. DEG. F

Suction Discharge

Drop F.

Air

DATA* Cooling

XQ05L10A-B 56 24 119 151 58 13 20 89 255 4.9 28.0 21.4 115 15

XQ06L10A-A 55 26 121 157 65 13 27 87 261 5.0 24.0 21.0 115 15

XQ08L10A-A 52 29 128 167 60 13 33 81 283 6.8 36.2 22.1 115 15

XQ10L10A-A 50 31 130 176 65 20 29 75 287 9.2 44.0 19.2 115 15

XQ12L10A-A 51 29 126 166 51 6 30 75 271 11.0 56.0 31.0 115 15

EQ08L11A-A 52 29 124 173 69 21 29 82 283 6.5 10.7 36.2 20.0 115 15

YQ07L10A-A 55 25 126 177 73 26 23 79 275 6.8 5.6 36.2 19.5 115 15

YQ07L10A-B 55 25 126 177 73 26 23 79 275 6.8 5.6 36.2 19.5 115 15

SS08L10-C 56 24 119 154 73 22 24 85 252 6.6 36.2 23.0 115 15

SS08L10-D 56 24 116 157 68 16 18 86 250-260 6.6 36.2 27.0 115 15

SS10L10-C 57 23 117 166 65 16 23 82 243 7.5 42.0 26.0 115 15

KS12L10-C 52 29 122 169 61 13 24 82 266 9.0 44.0 26.5 115 15

SS12L10-D 53 27 124 169 62 13 30 82 266 9.3 44.0 32.0 115 15

KS15L10-B 51 30 125 182 62 16 29 77 278 12.2 61.0 29.0 115 15

SS14L10-C 53 27 125 184 62 15 27 78 268 12.3 61.0 29.2 115 15

SS12L30-C 57 24 121 170 67 17 27 83 258 5.4 21.0 28.0 208 / 230 15

SS12L30-D 58 22 122 174 66 17 28 84 261 4.7 21.0 31.0 208 / 230 15

SH15L30-B 54 26 206 129 61 16 98 76 258 8.2 28.5 208 / 230 15

SS16L30-C 50 31 130 176 53 8 35 77 279 7.9 35.0 32.1 208 / 230 15

ES12L33-B 56 25 121 167 65 15 28 83 256 4.8 15.1 21.0 28.0 208 / 230 20

ES12L33-C 58 22 122 174 66 17 28 84 261 4.7 15.1 21.0 31.0 208 / 230 20

ES16L33-B 49 32 130 179 50 8 34 75 279 7.4 15.1 35.0 32.0 208 / 230 20

YS09L10-D 60 20 116 164 71 18 17 89 239 7.1 8.5 44.0 25.1 115 15

YS13L33-B 58 23 123 175 69 22 29 79 266 5.2 5.3 / 15.1 24.0 30.0 208 / 230 20

YS13L33-C 51 29 122 172 65 18 30 80 269 5.5/5.1 5.7/5.3 24.0 32.0 1 20

KM24L30-B 50 31 132 187 56 14 37 70 287 11.2 68.0 53.0 208 / 230 20

YM18L34-B 49 31 125 182 64 22 27 72 271 8.5 8.7 / 18.6 41.0 43.0 208 / 230 30

YM18L34-C 61 19 126 187 67 24 28 73 280 9.2/8.75 8.8/8.3 41.0 43.0 208/230 30

EM18L34-B 49 31 125 175 63 21 31 72 271 8.1 18.9 42.0 39.5 208 / 230 15

KM18L30-B 49 31 125 175 63 21 31 72 271 8.1 42.0 39.5 208 / 230 15

PERFORMANCE

*Rating Conditions: 80 degrees F, room air temp. & 50% relative humidity, with 95 degree F, outside air temp & 40% relative humidity.

Q-Chassis

S-Chassis

SM18L30A-B 53 28 122 175 66 13 25 82 255 7.3 37.0 44.0 208 / 230 15

SM18L30A-C 54 26 121 171 61 13 25 81 262 7.7/7.1 37.0 45.0 208/230 15

SM21L30-C 50 31 127 185 57 15 34 73 274 9.4 43.0 45.0 208 / 230 15

SM21L30-D 48 32 125 173 52 13 25 75 278 9.6/9.3 43.0 43.0 208/230 15

M-Chassis

EM24L35-B 50 31 132 187 56 14 37 70 287 11.2 25.0 68.0 53.0 208 / 230 30

SM24L30-B 50 31 132 187 56 14 37 70 287 11.2 68.0 53.0 208 / 230 20

SL28L30-C 53 28 128 172 56 13 29 73 259 13.0 68.0 50.1 208 / 230 20

SL36L30A-C 49 31 133 192 53 12 37 70 287 17.2 91.0 57.6 208 / 230 30

EL36L35A-C 49 32 133 194 53 13 38 70 302 18.0 25.0 91.0 60.0 208 / 230 30

YL24L35-C 52 29 122 175 65 23 29 72 262 10.9 11.2 / 24.6 68.0 74.0 208 / 230 30

YL24L35-D 52 28 124 175 65 22 29 74 268 11.9/11.1 11.7/11.0 68.0 73.0 208/230 30

SH15L30-B 54 26 206 129 61 16 98 76 258 8.2 28.5 208 / 230 15

SH20L30-B 46 34 125 196 52 8 28 75 271 10.1 39.0 208 / 230 20

L-Chassis

HazardGard

ELECTRICAL DATA

Wire Size Use ONLY wiring size recommended for

single outlet branch circuit. Fuse/Circuit Use ONLY type and size fuse or HACR Breaker c ircuit breaker indicated on unit ’s rating

plate. Proper current protection to the unit

is the responsibility of the owner. Grounding Unit MUST be grounded from branch

circuit through service cord to unit, or

through separate ground wire provided on

permanently connected units. Be sure that

branch circuit or general purpose outlet is

grounded. Receptacle The ﬁ eld supplied outlet must match plug on

service cord and be within reach of service

cord. Do NOT alter the service cord or plug.

Do NOT use an extension cord. Refer to

the table above for proper receptacle and

fuse type.

ELECTRIC SHOCK HAZARD.

T urn off electric power before service or installation. All electrical connections and wiring MUST be

installed by a qualiﬁ ed electrician and conform to the National Electrical Co de and all local codes which have jurisdiction.

Failure to do so can result in property damage, personal injury and/or death.

The consumer - through the AHAM Room Air Conditioner Certiﬁ cation Program - can be certain that the AHAM Certiﬁ cation Seal accurately states the unit’s cooling and heating capacity rating, the amperes and the energy efﬁ ciency ratio.

FUNCTIONAL COMPONENT DEFINITIONS

MECHANICAL C OMPONEN TS Bellows condensate valve Temperature-sensitive valve

that opens up to drain off condensate water when the outside temperature falls below 40°F and closes when the outside temperature reaches 58°F .

Ven t doo r Allows introduction of fresh air into the room and/or exhausts stale room air outside (on select models.)

Plenum assembly Diffuser with directional louvers used to direct the conditioned airﬂ ow.

Blower wheel Attaches to the indoor side of the fan motor shaft and is used for distributing unc onditione d, room side air though the heat exchanger and delivering conditioned air into the room.

Slinger fan bla d e Attaches to the outdoor side of the fan motor shaft and is used to move outside air through the condenser coil, while slinging condens ate water out of the base pan and onto the condenser coil, thus lowering the temperature and pressures within the coil.

ELECTRICAL COMPONENTS Thermostat Used to maint ain the speciﬁ ed room side

comfo rt level System switch Used to regulate the operation of the fan

motor, the compressor or to turn the unit off. For troubleshooting, refer to the wiring diagrams and schematics in the back of this service manual.

Capacitor Reduc es line cur rent and steadies the voltage supply, while greatly impro ving the torque characteristics of the fan motor and compressor motor.

ELECTRICAL COMPONENTS cont’d MoneySaver® switch When engaged, it sends the power

supply to the fan motor through the thermostat, which allows for a cycle-fan operation.

Fan M otor Dual-shafted fan motor operates the indoor blower wheel and the condenser fan blade simultaneously.

Solenoid Used to energize the reversing valve on all heat pump units.

Heating element Electric resistance heater, available in 3.3,

4.0 or 5.2 kW on select TwinTemp

models.

Heat anticipator Used to provide better thermostat and room air temperature control.

HERMETIC COMPONENTS Compressor Motorized device used to compress refrigerant

through the sealed system. Reversing valve A four-way switching device used on all

heat pump models to change the ﬂ ow of refrigerant to permit heating or cooling.

Check valve A pressure-operated device used to direct the ﬂ ow of refrigerant to the proper capillary tube, during either the heating or cooling cycle.

Capillary tube A cylindrical meter device used to evenly distribute the ﬂ ow of refrigerant to the heat exchangers (coils. )

ELECTRONIC CON TROLS

TESTING THE ELECTRONIC CONTROLS

CHECK FILTER light will come on after 250 hours of use.

Touch CHECK FILTER to reset.

Mode

Temp

Fan

Timer

Cool

Speed

Stop

Check

Set

Filter

Hour

Press to reset

Power

Money

Saver

1- 4

Smart

A/C

Start

Fan

Only

Fan

A/C

Timer

On/ Off

Electronic Control

ELECTRONIC CONTROLS

TESTING THE ELECTRONIC CONTROL XQ/WS BOARDS & QME BOARDS

Activating Test Mode: Activate test mode by pressing at the same time the “MODE” button and the temperature

“DOWN” button on XQ & WS models. LEDs for Hour, Start,

and Stop will blink 1 bps while T est Mode is active. Activate test mod e by pressing at the same time the “MONEY

SAVER” button and the “CHECK FILTER” button on QME models. LED for the Filter Alert will blink 1 bps w hile Test

Mode is active.

Test Mode has duration of 90 minutes. Test Mode can be

activated under any conditions, including Off. Test Mode is cancelled by pressing the On/Off button, unplugging the unit, or when the 90 minutes is timed out. All settings revert to the factory default settings of C ool, 75° F, Timer and Set Hour features are nonfunctional.

T est Mode overrides the three-minute lockout, all delays for

compressor and fan motor star t / speed change, and no delay when switching modes.

T est Mode default settings are ON, Money Saver , 60° F , and

High fan speed. Activating Error Code Mode : (Submode of T est Mode) Unit

must be in T est Mode to enter Error Code Mode Activate Error Code Mode by pressing the “TIMER ON/OFF”

button on XQ & WS models. LED for the “TIMER ON/OFF” will ﬂ ash 1 bps while Error Code Mode is active. Pressing the

“TEMP/HR + “ button will display 00. Consecutive presses

will scroll through all error codes logged. Press the “TEMP/ HR - “ button to see the reverse order of all error code s

logged. When the end of logged error codes is reached the

temperature set point will appear . Activate Error Code Mode by pressing at the same time the

“A/C START” button and the “ON/OFF” button on QME models.

LED for the “TIMER ON/OFF” will ﬂ ash 1 bps while Error Code Mode is active. Pressing the “WARMER” button will display 00. Consecutive presses will scroll through all error codes logged. Press the “COOLER” button to see the reverse order of all error codes logged. When the end of logged error codes is reached the temperature set point will appear.

TESTING THE ELECTRONIC CONTROL ERROR CODE LISTINGS

IMPORTANT: Error C odes are cleared from the

log by exiting from Error Code Mode. To e xit on XQ models, press Timer On/O ff button. To exit QME models, press A /C Start and On/Off buttons. Or unplug unit to exit Error Code Mode. Plug unit in after 5 seconds to resume normal operation of unit.

TESTING THE ELECTRONIC CONTROL

ERROR CODE LISTINGS E1 SHORT CYCLE SITUATION: Keyboard is fine.

Investigate and deﬁ ne short cycling problem. E2 KEYBOARD STUCK ERROR: If key button(s) are

pressed continuously for twenty seconds or more. If MODE key is stuck, unit will default to cool. Exit Error Code Mode to see if error “E2” is no longer displayed and unit is functioning. Replace board if “E2 ” still displays af ter exiting Error Code Mode.

E3 FROST PROBE OPEN: If ohm value is present, replace board.

E4 FROST PROBE SHORT: Replace board. E5 INDOOR PR OBE OP EN : R eplace board. E6 INDOOR PR OB E SH ORT: Replace board. NOTE: All Error Code displays for Frost & Indoor Probe will allow

unit to operate. Unit may or will ice up if faulty components not replaced.

FROST PROBE SENSOR: disables compressor at 35° F. INDOOR PROBE SENSOR: Control range is 60° F to 90°

F +/- 2° F.

Indoor temperature will be displayed by pressing: (QME units) The Fan Speed button and the Warmer button. (XQ u ni ts ) The Fan Speed button and the Temp Up button.

The indoor temperature will be displayed for 10 seconds. The display will change back to the Set Point temperature

by pressing any key button ex cept for the On/Off button. The indoor temperature can be viewed in all mo des, including test mode.

Check Filter: The Check Filter indicator turns on after the fan motor has been operating for 250 hours. The Check Filter indicator is reset by pressing the Check Filter button one time only, . Power failures will not reset the 250 hour timer. All time elapsed is stored in memory and resumes counting after power is restored.

Keep Alive: The electronic control has a memory to retain all functions and status as set up by the user in the event of a power failure. Once power is restored to the unit there is a two second delay before the fan comes on and approximately three minutes delay before the compressor is activated, providing that the mode was set for cooling and the set point temperature has not been met in the room.

REFRIGERATION SYSTEM SEQUENCE OF OPERATION

A good understanding of the basic operation of the refrigeration system is essential for the servic e technician. W ithout this understanding, accurate troubleshooting of refrigeration system proble ms wi l l be mor e d ifﬁ cult and time consuming, if not (in some cases) entirely impossible. The refrigeration system uses four basic principles (laws) in its operation they are as follows:

1. “Heat always ﬂ ows from a warmer body to a cooler body.”

2. “Heat must be added to or removed from a substance

before a change in state can occur”

3. “Flow is always from a higher pr essure area to a lower

pressure area.”

4. “The temperature at which a liquid or gas changes state

is dependent upon the pressure.”

The refrigeration cycle begins at the compressor. Starting

the compressor creates a low pres sure in the suction line which draws refrigerant gas (vapor) into the compressor.

The compressor then “compresses” this refrigerant, rais i ng

its pressure and its (heat intensity) T emperature .

The refrigerant leaves the compressor through the discharge

line as a hot high pressure gas (vapor). The refrigerant enters the condenser coil where it gives up some of its heat. The condenser fan moving air across the coil’s ﬁ nned surface facilitates the transfer of heat from the refr igerant to the relatively cooler outdoor air.

When a sufﬁ cient quantity of heat has been removed from the refrigerant gas (vapor), the refrigerant will “condense” (i.e . change to a liquid). Once the refrigerant has been condensed (changed) to a liquid it is cooled even further by the air that conti n u e s t o ﬂ ow across the condenser coil.

The RAC design determines at exactly what point (in the

condenser) the change of state (i.e. gas to a liquid) takes place. In all cases, however, the refrigerant must be totally condensed (changed) to a liquid before leaving the condenser coil.

The refrigerant leaves the condenser coil through the liquid

line as a warm high pressure liquid. It next will pass through the refrigerant drier (if so equipped). It is the function of the drier to trap any moisture present in the system, contaminants, and large particulate matter.

The liquid refrigerant next enters the metering device. The

metering device is a capillary tube. The pur pose of the metering device is to “meter” (i.e. control or measure) the quantity of refrigerant entering the evaporator coil.

In the case of the capillary tube this is accomplished (by design) through size ( and length) of de vice, and the pressure difference present across the device.

Since the evaporator coil is under a lower pressure (due to the suction created by the compressor) than the liquid line,

the liquid refrigerant leaves the metering device entering the evaporator coil. As it enters the evaporator coil, the larger area and lower pressure allows the refrigerant to expand and lower its temperature (heat intensity). This expansion is often referred to as “boiling”. Since the unit’s blower is moving Indoor air across the ﬁ nned surface of the evaporator coil, the expanding refrigerant absorbs some of that heat. This results in a lowering of the indoor air temperature, hence the “cooling” effect.

The expansion and absorbing of heat cause the liquid

refrigerant to evaporate (i.e. change to a gas). Once the refrigerant has been evaporated (changed to a gas), it is heated even further by the air that continues to ﬂ ow across the evaporator coil .

The particular system design determines at exactly what

point (in the evaporator) the change of state (i.e. liquid to a gas) takes place. In all cases, howev er, the refrigerant must be totally evaporated (changed ) to a gas before leaving the evaporator coil.

The low pressure (suction) created by the compressor

causes the refrigerant to leave the evaporator through the suction line as a cool low pressure vapor. The refrigerant then returns to the compressor, where the cycle is repeated.

Refrigerant System Components

Suction Line

Evaporator Coil

Metering Device

Refrigerant Dryer

Refrigerant Drier

SEALED REFRIGERATION SYSTEM REPAIRS

Discharge Line

Condenser Coil

Compressor

Liquid

Line

IMPORTANT

ANY SEALED SYSTEM REPAIRS TO COOL-ONLY MODELS REQUIRE THE INSTALLATION OF A LIQUID LINE DRIER. ALSO, ANY SEALED SYSTEM REPAIRS TO HEAT PUMP MODELS REQUIRE THE INSTALLA TION OF A SUCTION LINE DRIER.

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