Friedrich 2007 Air Conditioner User Manual

Service Manual
2007
Room Air Conditioners
Tempe
rature
Cooler
Warme
r
Cool
Powe
r
Fan
Fan
Only
Timer
On/Off
RAC-Svc-07 (4-07)
Money
Speed
Saver ®
Opera
tion
Start
Stop
Set Hr.
TABLE OF CONTENTS
Introduction / Typical Unit Components....................................................................................................................................... 3
Warranty ....................................................................................................................................................................................... 4
Routine Maintenance ................................................................................................................................................................... 5
Unit Identification / Nomenclature................................................................................................................................................ 6
Performance Data .........................................................................................................................................................................7
Electrical Data .............................................................................................................................................................................. 8
Functional Component Definitions .............................................................................................................................................. 9
Electronic Controls .................................................................................................................................................................. 9-10
Refrigeration Sequence of Operation.........................................................................................................................................11
Sealed Refrigeration Repairs.................................................................................................................................................11-12
Refrigerant Charging ............................................................................................................................................................. 13-15
Troubleshooting .....................................................................................................................................................................16-23
Wiring Diagrams ....................................................................................................................................................................24-35
The information contained in this manual is intended for use by a qualified service technician who is familiar
with the safety procedures required in installation and repair, and who is equipped with the proper tools and test
instruments.
Installation or repairs made by unqualified persons can result in hazards subjecting the unqualified person making
such repairs 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 responsibility for any bodily injury or property
damage which may result to you or others. Friedrich Air Conditioning Company will not be responsible for any
injury or property damage arising from improper installation, service, and/or service procedures.
2
INTRODUCTION
This service manual is designed to be used in conjunction with the installation manuals provided with each air conditioning
system component.
This service manual was written to assist the professional RAC service technician to quickly and accurately 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
Fresh Air
Compressor
Capillary Tube
Liquid Filter Driers
Reversing Valve
(some models)
Condenser Coil
Discharge Air
Front Cover
System Switches
Outdoor Grille
Evaporator Coil
Sleeve
Return Air Grille/Filter
Blower Wheel
Blower Motor
Basepan
Condenser Fan Blade
IMPORTANT: It will be necessary for you to accurately identify the unit you are servicing, so you can be certain of a proper
diagnosis and repair (See Unit Identification).
3
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.
2.
3.
Air filters or fuses.
Products on which the model and serial numbers have been removed.
Products which have defects or damage which results from improper installation, wiring, electrical current
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.
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.
(10-04)
4
ROUTINE MAINTENANCE
NOTE: Units are to be inspected and serviced by qualified service personnel only.
Routine maintenance is required annually or semi-annually, depending upon annual usage.
1. Clean the unit air intake filter at least every 250 to 300 fan hours of operation or when the unit’s indicator light is on if so
equipped. Clean the filters 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, etc.). 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 fin pack. Use a sweeping
up and down motion in the direction of the vertical aluminum fin 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 (voltmeter, ohmmeter, ammeter, wattmeter, etc.) to perform electrical tests.
Use an air conditioning or refrigeration thermometer to check room, outdoor and coil 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-yearly) and clean of all obstructions and debris.
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.
5
UNIT IDENTIFICATION
Model Number Code
S S 08 L 1 0
A
8th Digit – Engineering
1st Digit – Function
Major change
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
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
2nd Digit
C = Casement
Q = Q-Star
S = Small Chassis
M = Medium Chassis
L = Large Chassis
H = HazardGard
6th Digit – Voltage
1 = 115 Volts
3 = 230-208 Volts
5th Digit
3rd and 4th Digit - Approximate
BTU/HR (Cooling)
Alphabetical Modifier
Heating BTU/Hr capacity listed in the
Specification/Performance Data Section
RAC Serial Number Identification Guide
Serial Number
Decade Manufactured
L=0
C=3
F=6
A=1
D=4
G=7
B=2
E=5
H=8
Year Manufactured
A=1
D=4
G=7
J=9
K=0
C
G
R
00001
Production Run Number
Product Line
R = RAC
B=2
E=5
H=8
P = PTAC
C=3
F=6
J=9
E = EAC
Month Manufactured
A=Jan D=Apr G=Jul
B=Feb
V = VPAK
K=Oct
E=May H=Aug L=Nov
C=Mar F=Jun
6
L
J=Sept M=Dec
H = Split
Q-Chassis
S-Chassis
M-Chassis
L-Chassis
HazardGard
XQ05L10A-B
XQ06L10A-A
XQ08L10A-A
XQ10L10A-A
XQ12L10A-A
EQ08L11A-A
YQ07L10A-A
YQ07L10A-B
SS08L10-C
SS08L10-D
SS10L10-C
KS12L10-C
SS12L10-D
KS15L10-B
SS14L10-C
SS12L30-C
SS12L30-D
SH15L30-B
SS16L30-C
ES12L33-B
ES12L33-C
ES16L33-B
YS09L10-D
YS13L33-B
YS13L33-C
KM24L30-B
YM18L34-B
YM18L34-C
EM18L34-B
KM18L30-B
SM18L30A-B
SM18L30A-C
SM21L30-C
SM21L30-D
EM24L35-B
SM24L30-B
SL28L30-C
SL36L30A-C
EL36L35A-C
YL24L35-C
YL24L35-D
SH15L30-B
SH20L30-B
PERFORMANCE
DATA* Cooling
Discharge
Air
56
55
52
50
51
52
55
55
56
56
57
52
53
51
53
57
58
54
50
56
58
49
60
58
51
50
49
61
49
49
53
54
50
48
50
50
53
49
49
52
52
54
46
Temp.
Drop F.
24
26
29
31
29
29
25
25
24
24
23
29
27
30
27
24
22
26
31
25
22
32
20
23
29
31
31
19
31
31
28
26
31
32
31
31
28
31
32
29
28
26
34
EVAP. AIR TEMP. DEG. F
119
121
128
130
126
124
126
126
119
116
117
122
124
125
125
121
122
206
130
121
122
130
116
123
122
132
125
126
125
125
122
121
127
125
132
132
128
133
133
122
124
206
125
CONDENSER
TEMPERATURE
DEG. F
151
157
167
176
166
173
177
177
154
157
166
169
169
182
184
170
174
129
176
167
174
179
164
175
172
187
182
187
175
175
175
171
185
173
187
187
172
192
194
175
175
129
196
Discharge
Temp
58
65
60
65
51
69
73
73
73
68
65
61
62
62
62
67
66
61
53
65
66
50
71
69
65
56
64
67
63
63
66
61
57
52
56
56
56
53
53
65
65
61
52
13
13
13
20
6
21
26
26
22
16
16
13
13
16
15
17
17
16
8
15
17
8
18
22
18
14
22
24
21
21
13
13
15
13
14
14
13
12
13
23
22
16
8
20
27
33
29
30
29
23
23
24
18
23
24
30
29
27
27
28
98
35
28
28
34
17
29
30
37
27
28
31
31
25
25
34
25
37
37
29
37
38
29
29
98
28
Suction Super
SubTemp
Heat Cooling
89
87
81
75
75
82
79
79
85
86
82
82
82
77
78
83
84
76
77
83
84
75
89
79
80
70
72
73
72
72
82
81
73
75
70
70
73
70
70
72
74
76
75
255
261
283
287
271
283
275
275
252
250-260
243
266
266
278
268
258
261
258
279
256
261
279
239
266
269
287
271
280
271
271
255
262
274
278
287
287
259
287
302
262
268
258
271
Suction Discharge
OPERATING
PRESSURES
Amps
Cool
4.9
5.0
6.8
9.2
11.0
6.5
6.8
6.8
6.6
6.6
7.5
9.0
9.3
12.2
12.3
5.4
4.7
8.2
7.9
4.8
4.7
7.4
7.1
5.2
5.5/5.1
11.2
8.5
9.2/8.75
8.1
8.1
7.3
7.7/7.1
9.4
9.6/9.3
11.2
11.2
13.0
17.2
18.0
10.9
11.9/11.1
8.2
10.1
R-22
REF.
Locked
Charge
Rotor Amps in OZ.
28.0
21.4
24.0
21.0
36.2
22.1
44.0
19.2
56.0
31.0
10.7
36.2
20.0
5.6
36.2
19.5
5.6
36.2
19.5
36.2
23.0
36.2
27.0
42.0
26.0
44.0
26.5
44.0
32.0
61.0
29.0
61.0
29.2
21.0
28.0
21.0
31.0
28.5
35.0
32.1
15.1
21.0
28.0
15.1
21.0
31.0
15.1
35.0
32.0
8.5
44.0
25.1
5.3 / 15.1
24.0
30.0
5.7/5.3
24.0
32.0
68.0
53.0
8.7 / 18.6
41.0
43.0
8.8/8.3
41.0
43.0
18.9
42.0
39.5
42.0
39.5
37.0
44.0
37.0
45.0
43.0
45.0
43.0
43.0
25.0
68.0
53.0
68.0
53.0
68.0
50.1
91.0
57.6
25.0
91.0
60.0
11.2 / 24.6
68.0
74.0
11.7/11.0
68.0
73.0
28.5
39.0
Amps
Heat
ELECTRICAL RATINGS
115
115
115
115
115
115
115
115
115
115
115
115
115
115
115
208 / 230
208 / 230
208 / 230
208 / 230
208 / 230
208 / 230
208 / 230
115
208 / 230
1
208 / 230
208 / 230
208/230
208 / 230
208 / 230
208 / 230
208/230
208 / 230
208/230
208 / 230
208 / 230
208 / 230
208 / 230
208 / 230
208 / 230
208/230
208 / 230
208 / 230
Voltage
60 Hertz
Amps
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
20
20
20
15
20
20
20
30
30
15
15
15
15
15
15
30
20
20
30
30
30
30
15
20
BREAKER
FUSE
PERFORMANCE DATA
*Rating Conditions: 80 degrees F, room air temp. & 50% relative humidity, with 95 degree F, outside air temp & 40% relative humidity.
7
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
circuit breaker indicated on unit’s rating
plate. Proper current protection to the unit
is the responsibility of the owner.
ELECTRIC SHOCK HAZARD.
Turn off electric power before service or installation.
Grounding
Receptacle
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.
All electrical connections and wiring MUST be
installed by a qualified electrician and conform to the
National Electrical Code and all local codes which
have jurisdiction.
Failure to do so can result in property damage,
personal injury and/or death.
The field 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.
The consumer - through the AHAM Room Air Conditioner Certification Program - can be certain
that the AHAM Certification Seal accurately states the unit’s cooling and heating capacity rating,
the amperes and the energy efficiency ratio.
8
FUNCTIONAL COMPONENT DEFINITIONS
MECHANICAL COMPONENTS
ELECTRICAL COMPONENTS cont’d
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.
MoneySaver® switch When engaged, it sends the power
supply to the fan motor through the thermostat, which allows
for a cycle-fan operation.
Vent door 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 airflow.
Blower wheel Attaches to the indoor side of the fan motor
shaft and is used for distributing unconditioned, room side
air though the heat exchanger and delivering conditioned
air into the room.
Slinger fan blade Attaches to the outdoor side of the fan
motor shaft and is used to move outside air through the
condenser coil, while slinging condensate 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 maintain the specified room side
comfort 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.
Fan Motor 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 flow of refrigerant to permit
heating or cooling.
Check valve A pressure-operated device used to direct the
flow 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 flow of refrigerant to the heat exchangers (coils.)
Capacitor Reduces line current and steadies the voltage
supply, while greatly improving the torque characteristics of
the fan motor and compressor motor.
ELECTRONIC CONTROLS
TESTING THE ELECTRONIC CONTROLS
CHECK FILTER light will come on after 250 hours of use.
Touch CHECK FILTER to reset.
PM
Set
Hour
Check
Filter
Press to reset
Power
Mode
Cool
Money
Saver
Fan
Only
®
O
F / OC
Temp
Fan
Timer
1-4
Speed
A/C
Stop
Smart
Fan
A/C
Start
Timer
On/ Off
Electronic Control
9
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 Test Mode is active.
Activate test mode 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 while Test
Mode is active.
TESTING THE ELECTRONIC CONTROL
ERROR CODE LISTINGS
E1 SHORT CYCLE SITUATION: Keyboard is fine.
Investigate and define 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 after exiting Error Code
Mode.
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 Cool, 75° F, Timer and Set Hour
features are nonfunctional.
E3 FROST PROBE OPEN: If ohm value is present, replace
board.
Test Mode overrides the three-minute lockout, all delays for
compressor and fan motor start / speed change, and no
delay when switching modes.
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.
Test Mode default settings are ON, Money Saver, 60° F, and
High fan speed.
FROST PROBE SENSOR: disables compressor at 35° F.
Activating Error Code Mode: (Submode of Test Mode) Unit
must be in Test 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 flash 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 codes
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 flash 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 Codes are cleared from the
log by exiting from Error Code Mode. To exit on XQ
models, press Timer On/Off 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.
10
E4 FROST PROBE SHORT: Replace board.
E5 INDOOR PROBE OPEN: Replace board.
E6 INDOOR PROBE SHORT: Replace board.
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 units) 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 except for the On/Off button. The
indoor temperature can be viewed in all modes, 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 service technician. Without
this understanding, accurate troubleshooting of refrigeration
system problems will be more difficult 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 flows 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 pressure 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 pressure in the suction line
which draws refrigerant gas (vapor) into the compressor.
The compressor then “compresses” this refrigerant, raising
its pressure and its (heat intensity) Temperature.
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 finned surface
facilitates the transfer of heat from the refrigerant to the
relatively cooler outdoor air.
When a sufficient 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
continues to flow 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 purpose 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 device, and the pressure
difference present across the device.
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 finned 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 flow 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, however, 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
Discharge
Line
Evaporator
Coil
Condenser
Coil
Compressor
Metering
Device
Refrigerant
Dryer
Refrigerant Drier
Liquid
Line
SEALED REFRIGERATION SYSTEM REPAIRS
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
INSTALLATION OF A SUCTION LINE DRIER.
Since the evaporator coil is under a lower pressure (due to
the suction created by the compressor) than the liquid line,
11
EQUIPMENT REQUIRED
1.
Voltmeter
2.
Ammeter
3.
Ohmmeter
4.
E.P.A. Approved Refrigerant Recovery System.
5.
Vacuum Pump (capable of 200 microns or less vacuum.)
6.
Acetylene Welder
7.
Electronic Halogen Leak Detector (G.E. Type H-6 or
equivalent.)
8.
Accurate refrigerant charge measuring device such as:
a. Balance Scales - 1/2 oz. accuracy
b. Charging Board - 1/2 oz. accuracy
9.
High Pressure Gauge - (0 - 400 lbs.)
10.
Low Pressure Gauge - (30 - 150 lbs.)
11.
Vacuum Gauge - (0 - 1000 microns)
HERMETIC COMPONENT REPLACEMENT cont’d
6.
Pressurize system to 30 PSIG with proper refrigerant and
boost refrigerant pressure to 150 PSIG with dry nitrogen.
7.
Leak test complete system with electric halogen leak
detector, correcting any leaks found.
8.
Reduce the system to zero gauge pressure.
9.
Connect vacuum pump to high side and low side of
system with deep vacuum hoses, or copper tubing.
(Do not use regular hoses.)
10.
Evacuate system to maximum absolute holding
pressure of 200 microns or less. NOTE: This
process can be accelerated by use of heat lamps,
or by breaking the vacuum with refrigerant or dry
nitrogen at 5,000 microns. Pressure system to 5
PSIG and leave in system a minimum of 10 minutes.
Release refrigerant, and proceed with evacuation of
a pressure of 200 microns or less.
11.
Break vacuum by charging system from the high side
with the correct amount of liquid refrigerant specified.
This will prevent boiling the oil out of the crankcase,
and damage to the compressor due to over heating.
EQUIPMENT MUST BE CAPABLE OF:
1.
Recovery CFC’s as low as 5%.
2.
Evacuation from both the high side and low side of the
system simultaneously.
3.
Introducing refrigerant charge into high side of the
system.
4.
Accurately weighing the refrigerant charge actually
introduced into the system.
5.
Facilities for flowing nitrogen through refrigeration
tubing during all brazing processes.
HERMETIC COMPONENT REPLACEMENT
The following procedure applies when replacing components
in the sealed refrigeration circuit or repairing refrigerant
leaks. (Compressor, condenser, evaporator, capillary tube,
refrigerant leaks, etc.)
1.
Recover the refrigerant from the system at the process
tube located on the high side of the system by installing
a line tap on the process tube. Apply gauge from
process tube to EPA approved gauges from process
tube to EPA approved recovery system. Recover
CFC’s in system to at least 5%.
2.
Cut the process tube below pinch off on the suction
side of the compressor.
3.
Connect the line from the nitrogen tank to the suction
process tube.
4.
Drift dry nitrogen through the system and un-solder
the more distant connection first. (Filter drier, high side
process tube, etc.)
5.
Replace inoperative component, and always install a
new filter drier. Drift dry nitrogen through the system
when making these connections.
12
NOTE: If the entire charge will not enter the high side, allow
the remainder to enter the low side in small increments while
operating the unit.
12.
Restart unit several times after allowing pressures
to stabilize. Pinch off process tubes, cut and solder
the ends. Remove pinch off tool, and leak check the
process tube ends.
SPECIAL PROCEDURE IN THE CASE OF COMPRESSOR
MOTOR BURNOUT
1.
Recover all refrigerant and oil from the system.
2.
Remove compressor, capillary tube and filter drier from
the system.
3.
Flush evaporator condenser and all connecting
tubing with dry nitrogen or equivalent, to remove
all contamination from system. Inspect suction and
discharge line for carbon deposits. Remove and clean
if necessary.
4.
Reassemble the system, including new drier strainer
and capillary tube.
5.
Proceed with processing as outlined under hermetic
component replacement.
ROTARY COMPRESSOR SPECIAL TROUBLESHOOTING
AND SERVICE
Basically, troubleshooting and servicing rotary compressors
is the same as on the reciprocating compressor with only
one main exception:
NEVER, under any circumstances, charge a rotary
compressor through the LOW side. Doing so would
cause permanent damage to the new compressor.
REFRIGERANT CHARGING
NOTE: BECAUSE THE RAC SYSTEM IS A SEALED
SYSTEM, SERVICE PROCESS TUBES WILL HAVE TO BE
INSTALLED. FIRST INSTALL A LINE TAP AND REMOVE
REFRIGERANT FROM SYSTEM. MAKE NECESSARY
SEALED SYSTEM REPAIRS AND VACUUM SYSTEM.
CRIMP PROCESS TUBE LINE AND SOLDER END SHUT.
DO NOT LEAVE A SERVICE VALVE IN THE SEALED
SYSTEM.
Proper refrigerant charge is essential to proper unit operation.
Operating a unit with an improper refrigerant charge will
result in reduced performance (capacity) and/or efficiency.
Accordingly, the use of proper charging methods during
servicing will insure that the unit is functioning as designed
and that its compressor will not be damaged.
Too much refrigerant (overcharge) in the system is just as
bad (if not worse) than not enough refrigerant (undercharge).
They both can be the source of certain compressor failures if
they remain uncorrected for any period of time. Quite often,
other problems (such as low air flow across evaporator,
etc.) are misdiagnosed as refrigerant charge problems. The
refrigerant circuit diagnosis chart will assist you in properly
diagnosing these systems.
An overcharged unit will at times return liquid refrigerant
(slugging) back to the suction side of the compressor
eventually causing a mechanical failure within the compressor.
This mechanical failure can manifest itself as valve failure,
bearing failure, and/or other mechanical failure. The specific
type of failure will be influenced by the amount of liquid being
returned, and the length of time the slugging continues.
Not enough refrigerant (Undercharge) on the other hand,
will cause the temperature of the suction gas to increase to
the point where it does not provide sufficient cooling for the
compressor motor. When this occurs, the motor winding
temperature will increase causing the motor to overheat
and possibly cycle open the compressor overload protector.
Continued overheating of the motor windings and/or cycling
of the overload will eventually lead to compressor motor or
overload failure.
METHOD OF CHARGING
The acceptable method for charging the RAC system is the
Weighed in Charge Method. The weighed in charge method
is applicable to all units. It is the preferred method to use, as
it is the most accurate.
The weighed in method should always be used whenever
a charge is removed from a unit such as for a leak repair,
compressor replacement, or when there is no refrigerant
charge left in the unit. To charge by this method, requires
the following steps:
1.
Install a piercing valve to remove refrigerant from the
sealed system. (Piercing valve must be removed
from the system before recharging.)
2. Recover Refrigerant in accordance with EPA
regulations.
3. Install a process tube to sealed system.
4.
Make necessary repairs to system.
5. Evacuate system to 250 - 300 microns or less.
6. Weigh in refrigerant with the property quantity of
R-22 refrigerant.
7.
Start unit, and verify performance.
8. Crimp the process tube and solder the end shut.
NOTE: In order to access the sealed system it will be necessary to install Schrader type fittings to the process tubes
on the discharge and suction of the compressor. Proper refrigerant recovery procedures need to be adhered to as
outlined in EPA Regulations. THIS SHOULD ONLY BE ATTEMPTED BY QUALIFIED SERVICE PERSONNEL.
13
REFRIGERANT CHARGING cont’d
UNDERCHARGED REFRIGERANT SYSTEMS
An undercharged system will result in poor performance (low
pressures, etc.) in both the heating and cooling cycle.
Whenever you service a unit with an undercharge of
refrigerant, always suspect a leak. The leak must be repaired
before charging the unit.
To check for an undercharged system, turn the unit on, allow
the compressor to run long enough to establish working
pressures in the system (15 to 20 minutes).
During the cooling cycle you can listen carefully at the exit
of the metering device into the evaporator; an intermittent
hissing and gurgling sound indicates a low refrigerant charge.
Intermittent frosting and thawing of the evaporator is another
indication of a low charge, however, frosting and thawing can
also be caused by insufficient air over the evaporator.
Checks for an undercharged system can be made at the
compressor . If the compressor seems quieter than normal,
it is an indication of a low refrigerant charge. A check of the
amperage drawn by the compressor motor should show a
lower reading. (Check the Unit Specification.) After the unit
has run 10 to 15 minutes, check the gauge pressures.
Gauges connected to system with an undercharge will have
low head pressures and substantially low suction pressures.
NOTE: Heat pump
refrigeration
drawing
OVERCHARGED REFRIGERANT SYSTEMS
Compressor amps will be near normal or higher. Noncondensables can also cause these symptoms. To confirm,
remove some of the charge, if conditions improve, system
may be overcharged. If conditions don’t improve, Noncondensables are indicated.
Whenever an overcharged system is indicated, always make
sure that the problem is not caused by air flow problems.
Improper air flow over the evaporator coil may indicate some
of the same symptoms as an overcharged system.
14
An over charge can cause the compressor to fail, since it
would be “slugged” with liquid refrigerant.
The charge for any system is critical. When the compressor
is noisy, suspect an overcharge, when you are sure that the
air quantity over the evaporator coil is correct. Icing of the
evaporator will not be encountered because the refrigerant
will boil later if at all. Gauges connected to system will usually
have higher head pressure (depending upon amount of
overcharge). Suction pressure should be slightly higher.
REFRIGERANT CHARGING cont’d
RESTRICTED REFRIGERANT SYSTEM
A quick check for either condition begins at the evaporator.
With a partial restriction, there may be gurgling sounds at the
metering device entrance to the evaporator. The evaporator
in a partial restriction could be partially frosted or have an ice
ball close to the entrance of the metering device. Frost may
continue on the suction line back to the compressor.
Often a partial restriction of any type can be found by feel,
as there is a temperature difference from one side of the
restriction to the other.
With a complete restriction, there will be no sound at the metering device entrance. An amperage check of the compressor with a partial restriction may show normal current when
compared to the unit specification. With a complete restriction
the current drawn may be considerably less than normal, as
the compressor is running in a deep vacuum (no load). Much
of the area of the condenser will be relatively cool since most
or all of the liquid refrigerant will be stored there.
Troubleshooting a restricted refrigerant system can
be difficult. The following procedures are the more
common problems and solutions to these problems.
There are two types of refrigerant restrictions: Partial
restrictions and complete restrictions.
• A partial restriction allows some of the refrigerant to
circulate through the system.
• With a complete restriction there is no circulation of
refrigerant in the system.
• Restricted refrigerant systems display the same
symptoms as a “low-charge condition.”
• When the unit is shut off, the gauges may equalize very
slowly.
• Gauges connected to a completely restricted system
will run in a deep vacuum. When the unit is shut off, the
gauges will not equalize at all.
The following conditions are based primarily on a system in
the cooling mode.
15
TROUBLESHOOTING TOUCH TEST CHART: TO SERVICE REVERSING VALVES
RIGHT Pilot
Capillary Tube
1
2
3
4
5
6
Cool
Cool
as (2)
Hot
as (1)
*TVB
TVB
Cool
Hot
as (1)
Cool
as (2)
*TVB
TVB
Hot
Hot
Tube to INSIDE
COIL
LEFT Pilot
Capillary Tube
Normal Heating
Tube to OUTSIDE
COIL
Normal Cooling
SUCTION TUBE to
Compressor
VALVE
OPERATING
CONDITION
DISCHARGE TUBE
from Compressor
NORMAL FUNCTION OF VALVE
NOTES:
* TEMPERATURE OF VALVE BODY
** WARMER THAN VALVE BODY
POSSIBLE CAUSES
CORRECTIONS
MALFUNCTION OF VALVE
Check Electrical circuit and coil
Check refrigeration charge
Valve will not
shift from cool
to heat.
Valve will not
shift from cool
to heat.
Starts to shift
but does not
complete
reversal.
Apparent
leap in heating.
Hot
Cool
Hot,
as (1)
*TVB
Repair electrical circuit.
Defective coil.
Replace coil.
Low charge.
Repair leak, recharge system.
Pressure differential too high.
Recheck system.
Hot
Pilot valve okay. Dirt in one bleeder hole.
Hot
Cool
Cool,
as (2)
Hot,
as (1)
*TVB
*TVB
Hot
Cool
Cool,
as (2)
Hot,
as (1)
Hot
Hot
Warm
Cool
Cool,
as (2)
Hot,
as (1)
*TVB
Warm
Hot
Warm
Warm
Hot
*TVB
Hot
De-energize solenoid, raise head pressure, reenergize solenoid to break dirt
loose. If unsuccessful, remove valve, wash
out. Check on air before installing. If no
movement, replace valve, add strainer to
discharge tube, mount valve horizontally.
Piston cup leak
Stop unit. After pressures equalize, restart
with solenoid energized. If valve shifts,
reattempt with compressor running. If still
no shift, replace valve.
Clogged pilot tubes.
Raise head pressure, operate solenoid to
free. If still no shift, replace valve.
Both ports of pilot open. (Back seat port did
not close).
Raise head pressure, operate solenoid to
free partially clogged port. If still no shift,
replace valve.
Defective Compressor.
Replace compressor
Not enough pressure differential at start of
stroke or not enough flow to maintain pressure differential.
Check unit for correct operating pressures
and charge. Raise head pressure. If no
shift, use valve with smaller port.
Body damage.
Replace valve
Hot
Warm
Warm
Hot
Hot
Hot
Both ports of pilot open.
Raise head pressure, operate solenoid.
If no shift, use valve with smaller ports.
Hot
Hot
Hot
Hot
*TVB
Hot
Body damage.
Replace valve
Valve hung up at mid-stroke. Pumping volume of compressor not sufficient to maintain
reversal.
Raise head pressure, operate solenoid.
If no shift, use valve with smaller ports.
Both ports of pilot open.
Raise head pressure, operate solenoid.
If no shift, replace valve.
Piston needle on end of slide leaking.
Operate valve several times, then recheck.
If excessive leak, replace valve.
Pilot needle and piston needle leaking.
Operate valve several times, then recheck.
If excessive leak, replace valve.
Pressure differential too high.
Stop unit. Will reverse during equalization
period. Recheck system
Clogged pilot tube.
Raise head pressure, operate solenoid to
free dirt. If still no shift, replace valve.
Dirt in bleeder hole.
Raise head pressure, operate solenoid.
Remove valve and wash out. Check on
air before reinstalling, if no movement,
replace valve. Add strainer to discharge
tube. Mount valve horizontally.
Hot
Hot
Hot
Hot
Hot
Hot
Hot
Cool
Hot,
as (1)
Cool,
as (2)
*TVB
*TVB
Hot
Cool
Hot,
as (1)
Cool,
as (2)
Hot
Cool
Hot,
as (1)
Cool,
as (2)
** WVB ** WVB
*TVB
*TVB
Cool
Hot,
as (1)
Cool,
as (2)
Hot
Cool
Hot,
as (1)
Cool,
as (2)
Hot
*TVB
Piston cup leak.
Stop unit. After pressures equalize, restart
with solenoid de-energized. If valve shifts,
reattempt with compressor running. If it
still will not reverse while running, replace
the valve.
Hot
Cool
Hot,
as (1)
Cool,
as (2)
Hot
Hot
Defective pilot.
Replace valve.
Warm
Cool
Warm,
as (1)
Cool,
as (2)
Warm
*TVB
Defective compressor.
Replace compressor
Hot
Will not shift
from heat to
cool.
16
Cool,
as (2)
No voltage to coil.
Hot
*TVB
COOLING ONLY ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS
Problem
Compressor
does not run
Possible Cause
Low voltage
Check voltage at compressor. 115V & 230V units
will operate at 10% voltage variance
T-stat not set cold enough or inoperative
Set t-stat to coldest position. Test t-stat & replace
if inoperative
Compressor hums but cuts off on B10 overload
Hard start compressor. Direct test compressor. If
compressor starts, add starting components
Open or shorted compressor windings
Check for continuity & resistance
Open overload
Test overload protector & replace if inoperative
Open capacitor
Test capacitor & replace if inoperative
Inoperative system switch
Test for continuity in all positions. Replace if
inoperative
Broken, loose or incorrect wiring
Refer to appropriate wiring diagrams to check
wiring
Problem
Fan motor
does not run
Possible Cause
Action
Inoperative system switch
Test switch & replace if inoperative
Broken, loose or incorrect wiring
Refer to applicable wiring diagram
Open capacitor
Test capacitor & replace if inoperative
Fan speed switch open
Test switch & replace if inoperative
Inoperative fan motor
Test fan motor & replace if inoperative (be sure
internal overload has had time to reset)
Problem
Does not cool or
only cools slightly
Action
Possible Cause
Action
Undersized unit
Refer to industry standard sizing chart
T-stat open or inoperative
Set to coldest position. Test t-stat & replace if
necessary
Dirty filter
Clean as recommended in Owner's Manual
Dirty or restricted condenser or evaporator coil
Use pressure wash or biodegradable cleaning
agent to clean
Poor air circulation
Adjust discharge louvers. Use high fan speed
Fresh air or exhaust air door open on applicable
models
Close doors. Instruct customer on use of this
feature
Low capacity - undercharge
Check for leak & make repair
Compressor not pumping properly
Check amperage draw against nameplate. If not
conclusive, make pressure test
17
COOLING ONLY ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS
Problem
Unit does not run
Possible Cause
Fuse blown or circuit tripped
Replace fuse, reset breaker. If repeats, check
fuse or breaker size. Check for shorts in unit
wiring & components
Power cord not plugged in
Plug it in
System switch in "OFF" position
Set switch correctly
Inoperative system switch
Test for continuity in each switch position
Loose or disconnected wiring at switch or other
components
Check wiring & connections. Reconnect per
wiring diagram
Problem
Evaporator coil
freezes up
Possible Cause
Clean as recommended in Owner's Manual
Restricted airflow
Check for dirty or obstructed coil. Use pressure
wash or biodegradable cleaning agent to clean
Inoperative t-stat
Test for shorted t-stat or stuck contacts
Short of refrigerant
De-ice coil & check for leak
Inoperative fan motor
Test fan motor & replace if inoperative
Partially restricted capillary tube
De-ice coil. Check temp. differential (delta T)
across coil. Touch test coil return bends for same
temp. Test for low running current
Possible Cause
18
Action
Excessive heat load
Unit undersized. Test cooling performance &
replace with larger unit if needed
Restriction in line
Check for partially iced coil & check temperature
split across coil
Refrigerant leak
Check for oil at silver soldered connections.
Check for partially iced coil. Check split across
coil. Check for low running amperage
T-stat contacts stuck
Check operation of t-stat. Replace if contacts
remain closed.
T-stat incorrectly wired
Refer to appropriate wiring diagram
Problem
T-stat does not turn
unit off
Action
Dirty filter
Problem
Compressor runs
continually & does
not cycle off
Action
Possible Cause
Action
T-stat contacts stuck
Disconnect power to unit. Remove cover of t-stat
& check if contacts are stuck. If so, replace t-stat
T-stat set at coldest point
Turn to higher temp. setting to see if unit cycles
off
Incorrect wiring
Refer to appropriate wiring diagrams
Unit undersized for area to be cooled
Refer to industry standard sizing chart
COOLING ONLY ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS
Problem
Compressor runs for
short periods only.
Cycles on overload
Possible Cause
Overload inoperative. Opens too soon
Check operation of unit. Replace overload if
system operation is satisfactory
Compressor restarted before system pressures
equalized
Allow a minimum of 2 minutes to allow pressures
to equalize before attempting to restart. Instruct
customer of waiting period
Low or fluctuating voltage
Check voltage with unit operating. Check for
other appliances on circuit. Air conditioner should
be in separate circuit for proper voltage & fused
separately
Incorrect wiring
Refer to appropriate wiring diagram
Shorted or incorrect capacitor
Check by substituting a known good capacitor of
correct rating
Restricted or low air flow through condenser coil
Check for proper fan speed or blocked
condenser
Compressor running abnormally hot
Check for kinked discharge line or restricted
condenser. Check amperage
Problem
T-stat does not
turn unit on
Possible Cause
Problem
Water leaks into the
room
Action
Loss of charge in t-stat bulb
Place jumper across t-stat terminals to check if
unit operates. If unit operates, replace t-stat.
Loose or broken parts in t-stat
Check as above
Incorrect wiring
Refer to appropriate wiring diagram
Problem
Noisy operation
Action
Possible Cause
Action
Poorly installed
Refer to Installation Manual for proper installation
Fan blade striking chassis
Reposition - adjust motor mount
Compressor vibrating
Check that compressor grommets have not
deteriorated. Check that compressor mounting
parts are not missing
Improperly mounted or loose cabinet parts
Check assembly & parts for looseness, rubbing
& rattling
Possible Cause
Action
Evaporator drain pan overflowing
Clean obstructed drain trough
Condensation forming on base pan
Evaporator drain pan broken or cracked. Reseal
or replace
Poor installation resulting in rain entering the
room
Check installation instructions. Reseal as
required
Condensation on discharge grille louvers
Clean the dirty evaporator coil. Use pressure
wash or biodegradable cleaning agent to clean
Chassis gasket not installed
Install gasket, per Installation manual
Downward slope of unit is too steep
Refer to installation manual for proper installation
19
COOLING ONLY ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS
Problem
Possible Cause
Sublimation:
When
unconditioned saturated, outside air mixes with
conditioned air, condensation forms on the cooler
surfaces
Ensure that foam gaskets are installed in
between window panes & in between the unit &
the sleeve. Also, ensure that fresh air/exhaust
vents (on applicable models) are in the closed
position & are in tact
Downward pitch of installation is too steep
Follow installation instructions to ensure that
downward pitch of installed unit is no less than
1/4" & no more than 3/8"
Restricted coil or dirty filter
Clean & advise customer of periodic cleaning &
maintenance needs of entire unit
Water "spitting"
into room
Problem
Excessive moisture
Problem
Possible Cause
Adjust louvers for best possible air circulation
Oversized unit
Operate in "MoneySaver" position
Inadequate vapor barrier in building structure,
particularly floors
Advise customer
Possible Cause
Prolonged off
cycles (automatic
operation)
Action
Replace t-stat
Plenum gasket not sealing, allowing discharge air
Check gasket. Reposition or replace as needed
to short cycle t-stat
Restricted coil or dirty filter
Problem
Action
Insufficient air circulation thru area to be air
conditioned
T-stat differential too narrow
T-stat short cycles
Action
Clean & advise customer of periodic cleaning &
maintenance needs of entire unit
Possible Cause
Action
Anticipator (resistor) wire disconnected at t-stat
or system switch
Refer to appropriate wiring diagram
Anticipator (resistor) shorted or open
Disconnect plus from outlet. Remove resistor
from bracket. Insert plug & depress "COOL"
& "FAN AUTOMATIC" buttons. Place t-stat to
warmest setting. Feel resistor for temperature. If
no heat, replace resistor
Partial loss of charge in t-stat bulb causing a wide
Replace t-stat
differential
Problem
Possible Cause
Evaporator drain pan cracked or obstructed
Repair, clean or replace as required
Water in compressor area
Detach shroud from pan & coil. Clean & remove
old sealer. Reseal, reinstall & check
Obstructed condenser coil
Use pressure wash or biodegradable cleaning
agent to clean
Fan blade/slinger ring improperly positioned
Adjust fan blade to 1/2" of condenser coil
Outside water leaks
20
Action
HEAT / COOL ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS
Problem
Possible Cause
Heat anticipator (resistor) shorted (on applicable
models)
Room temperature
uneven
(Heating cycle)
Disconnect power to unit. Remove resistor from
t-stat bulb block. Plus in unit & allow to operate.
Feel resistor for heat. If not heat, replace resistor
Wide differential - partial loss of t-stat bulb charge Replace t-stat & check
Refer to appropriate wiring diagram. Resistor is
energized during "ON" cycle of compressor or
fan.
Incorrect wiring
Problem
Unit will not defrost
Action
Possible Cause
Action
Incorrect wiring
Refer to appropriate wiring diagram
Defrost control timer motor not advancing
(applicable models)
Check for voltage at "TM" & "TM1" on timer. If no
voltage, replace control
Defrost control out of calibration (applicable
models)
If outside coil temperature is 25F or below, &
preselected time limit has elapsed, replace
defrost control
Defrost control contacts stuck
If contacts remain closed between terminals "2"
& "3" of the defrost control after preselected time
interval has passed, replace control
Defrost control bulb removed from or not making
good coil contact
Reinstall & be assured that good bulb to coil
contact is made
Problem
Possible Cause
Action
Exhaust or fresh air door open
Check if operating properly. Instruct customer on
proper use of control
Dirty filter
Clean as recommended in Owner's Manual
Unit undersized
Check heat rise across coil. If unit operates
efficiently, check if insulation can be added
to attic or walls. If insulation is adequate,
recommend additional unit or larger one
Outdoor t-stat open (applicable models)
T-stat should close at 38°F. Check continuity of
control. If temperature is below 38°F, replace
control
Heater hi-limit control cycling on & off
Check for adequate fan air across heater. Check
control for open at 160°F & close at 150°F
Shorted supplementary heater
Ohmmeter check, approx. 32-35 ohms
Incorrect wiring
Check applicable wiring diagram
Does not heat
adequately
21
HEAT / COOL ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS
Problem
Unit cools when
heat is called for
Possible Cause
Incorrect wiring
Refer to applicable wiring diagram
Defective solenoid coil
Check for continuity of coil
Reversing valve fails to shift
Block condenser coil & switch unit to cooling.
Allow pressure to build up in system, then
switch to heating. If valve fails to shift, replace
valve.
Inoperative system switch
Check for continuity of system switch
Problem
Cooling adequate,
but heating
insufficient
Action
Possible Cause
Action
Heating capillary tube partially restricted
Check for partially starved outer coil. Replace
heating capillary tube
Check valve leaking internally
Switch unit several times from heating to
cooling. Check temperature rise across
coil. Refer to specification sheet for correct
temperature rise
Reversing valve failing to shift completely;
bypassing hot gas
De-energize solenoid coil, raise head
pressure, energize solenoid to break loose.
If valve fails to make complete shift, replace
valve.
TROUBLESHOOTING CHART — COOLING
REFRIGERANT SYSTEM DIAGNOSIS – HEATING
22
Low Suction Pressure
High Suction Pressure
Low Head Pressure
High Head Pressure
Low Load Conditions
High Load Conditions
Low Load Conditions
High Load Conditions
Low Air Flow Across
Indoor Coil
High Air Flow Across
Indoor Coil
Refrigerant System
Restriction
Low Air Flow Across
Outdoor Coil
Refrigerant System
Restriction
Reversing Valve not
Fully Seated
Reversing Valve not
Fully Seated
Overcharged
Undercharged
Overcharged
Undercharged
in System
Noncondensables (air)
Moisture in System
Defective Compressor
Defective Compressor
TROUBLESHOOTING CHART — HEATING
REFRIGERANT SYSTEM DIAGNOSIS – HEATING
Low Suction Pressure
High Suction Pressure
Low Head Pressure
High Head Pressure
Low Airflow
Across Outdoor Coil
Outdoor Ambient Too High
for Operation in Heating
Refrigerant System
Restriction
Outdoor Ambient Too High
For Operation In Heating
Refrigerant System
Restriction
Reversing Valve not
Fully Seated
Reversing Valve not
Fully Seated
Low Airflow Across
Indoor Coil
Undercharged
Overcharged
Undercharged
Overcharged
Moisture in System
Defective Compressor
Defective Compressor
Noncondensables (air)
ELECTRICAL TROUBLESHOOTING CHART — HEAT PUMP
HEAT PUMP
SYSTEM COOLS WHEN
HEATING IS DESIRED.
Is Line Voltage
Present at the Solenoid
NO
Is the Selector Switch
Set for Heat?
YES
Replace the Solenoid Coil
Is the Solenoid Coil Good?
NO
YES
Reversing Valve Stuck
Replace the Reversing Valve
23
MODELS
XQ05L10-A,B; XQ06L10-A,B,C,D; XQ08L10-A,B; XQ10L10-A,B; XQ12L10-A,B
24
MODELS
KS10L10-A, RS10L10-A, KS12L10-A, KS12L30-A, KS15L10-A, RS15L10-A, RS16L30-A,
RM18L30-A, KM18L30-A, KM21L30-A, RM24L30-A, KM24L30-A
25
MODELS
SS08L10-A/B, SS10L10-A/B, SS12L10-A/B; SS12L30-A/B, SS14L10-A/B,
SS16L30-A/B, SM18L30-A/B, SM21L30-A/B, SM24L30-A/B
26
MODEL
SL36L30-A
27
MODEL
SL28L30-A
28
MODELS
SL36L30-B
29
MODEL
EQ08L11-A
30
MODELS
ES12L33-A, ES16L33-A, EM18L34-A, EM24L35-A
31
MODEL
EL36L35-A
32
MODEL
YS09L10-A, YS09L10-B
33
MODELS
YS13L33-A, YM18L34-A
34
MODELS
YL24L35-A
35
Friedrich Air Conditioning Co.
Post Office Box 1540 • San Antonio, Texas 78295-1540
4200 N. Pan Am Expressway • San Antonio, Texas 78218-5212
(210) 357-4400 • FAX (210) 357-4480
www.friedrich.com
Printed in the U.S.A.
RAC-Svc-07 (4-07)