Friedrich CP05 User Manual

Service Manual  
2006  
Room Air Conditioners  
ust  
Exha  
NCY  
H
EF  
FICIE  
HIG  
PM  
SUPER  
er  
Pow  
ff  
On/O  
Cool  
®
r
ySave  
Mone  
Fan  
pee  
Mode  
Set  
d
O
nly  
S
Fan  
Clock  
Start  
Stop  
r
Time  
r
Hou  
ff  
On/O  
ur  
p/Ho  
Tem  
Vent  
s
hut  
RAC-Svc-06 (3-06)  
Friedrich Air Conditioning Company  
P.O. Box 1540  
San Antonio, TX 78295  
210.357.4400  
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  
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)  
3
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.  
4
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  
7th Digit – Options  
0 = Straight Cool &  
Heat Pump Models  
W = Thru-the Wall,  
WallMaster Series  
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  
Alphabetical Modifier  
BTU/HR (Cooling)  
Heating BTU/Hr capacity listed in the  
Specification/Performance Data Section  
RAC Serial Number Identification Guide  
Serial Number  
L
C
G
R
00001  
Decade Manufactured  
L=0  
A=1  
B=2  
C=3  
D=4  
E=5  
F=6  
G=7  
H=8  
J=9  
Production Run Number  
Year Manufactured  
Product Line  
A=1  
B=2  
C=3  
D=4  
E=5  
F=6  
G=7  
H=8  
J=9  
K=0  
R = RAC  
P = PTAC  
E = EAC  
V = VPAK  
H = Split  
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  
5
PERFORMANCE DATA  
OPERATING  
PRESSURES  
R-22  
REF.  
BREAKER  
FUSE  
CONDENSER DISCHARGE SUCTION SUPER  
SUB-  
EVAPORATOR  
AIR TEMP °F  
ELECTRICAL RATINGS  
Locked  
TEMP °F  
TEMP  
TEMP  
HEAT COOLING  
Voltage  
Model  
Temp  
Amps  
Suction Discharge Cool  
Amps  
Heat  
Rotor Charge  
Discharge  
Air  
60 Hertz  
Amps  
Drop °F  
Amps  
in OZ.  
Q-Chassis  
XQ05L10-A  
XQ06L10-A  
XQ08L10-A  
XQ10L10-A  
XQ12L10-A  
EQ08L11-A  
54  
55  
52  
50  
51  
52  
27  
26  
29  
31  
29  
29  
120  
121  
128  
130  
126  
124  
150  
157  
167  
176  
166  
173  
68  
65  
60  
65  
51  
69  
17  
13  
13  
20  
6
19  
27  
33  
29  
30  
29  
85  
87  
81  
75  
75  
82  
256  
261  
283  
287  
271  
283  
4.8  
5.0  
6.8  
9.2  
11.0  
6.5  
28.0  
24.0  
36.2  
44.0  
56.0  
36.2  
18.3  
21.0  
22.1  
19.2  
31.0  
20.0  
115  
115  
115  
115  
115  
115  
15  
15  
15  
15  
15  
15  
21  
10.7  
S-Chassis  
SS08L10-B  
KS10L10-A  
RS10L10-A  
SS10L10-B  
KS12L10-A  
RS12L10-A  
SS12L10-B  
KS15L10-A  
RS15L10-A  
SS14L10-B  
KS12L30-A  
SS12L30-B  
SS16L30-B  
RS16L30-A  
ES12L33-A  
ES16L33-A  
YS09L10-A  
YS09L10-B  
YS09L10A-A  
YS13L33-A  
56  
52  
58  
57  
52  
53  
53  
51  
53  
53  
48  
57  
50  
50  
56  
49  
60  
60  
60  
58  
24  
29  
23  
23  
29  
27  
27  
30  
27  
27  
32  
24  
31  
31  
25  
32  
20  
20  
20  
23  
119  
117  
117  
117  
122  
124  
124  
125  
125  
125  
129  
121  
130  
130  
121  
130  
116  
116  
116  
123  
154  
162  
166  
166  
169  
169  
169  
182  
184  
184  
176  
170  
176  
176  
167  
179  
164  
164  
164  
175  
68  
64  
68  
65  
61  
62  
62  
62  
62  
62  
48  
67  
53  
53  
65  
50  
71  
71  
71  
69  
13  
15  
15  
16  
13  
13  
13  
16  
16  
15  
34  
17  
8
8
15  
8
18  
18  
18  
22  
26  
21  
21  
23  
24  
30  
30  
29  
27  
27  
36  
27  
35  
35  
28  
34  
17  
17  
17  
29  
85  
83  
83  
82  
82  
82  
82  
77  
77  
78  
76  
83  
77  
77  
83  
75  
89  
89  
89  
79  
252  
244  
244  
243  
266  
266  
266  
278  
278  
268  
287  
258  
279  
279  
256  
279  
239  
239  
239  
266  
6.6  
8.0  
8.0  
7.5  
9.0  
9.3  
9.3  
12.2  
12.3  
12.3  
12.3  
5.4  
7.9  
36.2  
42.0  
42.0  
42.0  
44.0  
44.0  
44.0  
61.0  
61.0  
61.0  
24.0  
21.0  
35.0  
35.0  
21.0  
35.0  
44.0  
44.0  
44.0  
24.0  
23.0  
26.0  
26.0  
26.0  
26.5  
32.0  
32.0  
29.0  
29.0  
29.2  
115  
115  
115  
115  
115  
115  
115  
115  
115  
115  
15  
15  
15  
15  
15  
15  
15  
15  
15  
15  
15  
15  
15  
15  
20  
20  
15  
15  
15  
20  
31.0 208 / 230  
28.0 208 / 230  
32.1 208 / 230  
32.0 208 / 230  
28.0 208 / 230  
32.0 208 / 230  
25.1  
25.1  
25.1  
7.4  
4.8  
7.4  
7.1  
7.1  
15.1  
15.1  
8.5  
8.5  
8.5  
115  
115  
115  
7.1  
5.2  
5.3 / 15.1  
30.0 208 / 230  
M-Chassis  
KM24L30-A  
RM24L30-A  
YM18L34-A  
RM18L30-A  
EM18L34-A  
KM18L30-A  
SM18L30-A  
KM21L30-A  
SM21L30-A  
EM24L35  
50  
50  
49  
49  
49  
49  
53  
50  
50  
50  
50  
31  
31  
31  
31  
31  
31  
28  
31  
31  
31  
31  
132  
132  
125  
125  
125  
125  
122  
127  
127  
132  
132  
187  
187  
182  
175  
175  
175  
175  
185  
185  
187  
187  
56  
56  
64  
63  
63  
63  
66  
57  
57  
56  
56  
14  
14  
22  
21  
21  
21  
13  
15  
15  
14  
14  
37  
37  
27  
31  
31  
31  
25  
34  
34  
37  
37  
70  
70  
72  
72  
72  
72  
82  
73  
73  
70  
70  
287  
287  
271  
271  
271  
271  
255  
274  
274  
287  
287  
11.2  
11.2  
8.5  
8.7  
8.1  
8.1  
7.3  
9.4  
9.4  
68.0  
68.0  
41.0  
42.0  
42.0  
42.0  
37.0  
43.0  
43.0  
68.0  
68.0  
53.0 208 / 230  
53.0 208 / 230  
43.0 208 / 230  
39.5 208 / 230  
39.5 208 / 230  
39.5 208 / 230  
44.0 208 / 230  
45.0 208 / 230  
45.0 208 / 230  
53.0 208 / 230  
53.0 208 / 230  
20  
20  
30  
15  
15  
15  
15  
15  
15  
30  
20  
8.7 / 18.6  
18.9  
25.0  
11.2  
11.2  
SM24L30  
L-Chassis  
SL28L30-A  
SL36L30-A  
SL36L30-B  
EL36L35-A  
YL24L35-A  
53  
49  
49  
49  
52  
28  
31  
31  
32  
29  
128  
133  
133  
133  
122  
172  
192  
192  
194  
175  
56  
53  
53  
53  
65  
13  
12  
12  
13  
23  
29  
37  
37  
38  
29  
73  
70  
70  
70  
72  
259  
287  
287  
302  
262  
13.0  
17.2  
17.2  
18.0  
68.0  
91.0  
91.0  
91.0  
50.1 208 / 230  
57.6 208 / 230  
57.6 208 / 230  
60.0 208 / 230  
74.0 208 / 230  
20  
30  
30  
30  
30  
25.0  
10.9 11.2 / 24.6 68.0  
Casement  
SC06L10-A  
47  
33  
128  
166  
47  
14  
23  
74  
290  
6.7  
40.0  
20.0  
115  
15  
HazardGard  
SH15L30-A  
SH20L30-A  
54  
46  
26  
34  
206  
125  
129  
196  
61  
52  
16  
8
98  
28  
76  
75  
258  
271  
8.2  
10.1  
28.5 208 / 230  
39.0 208 / 230  
15  
20  
6
ELECTRICAL DATA  
Wire Size  
Use ONLY wiring size recommended for  
single outlet branch circuit.  
Fuse/Circuit  
Breaker  
Use ONLY type and size fuse or HACR  
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  
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.  
Receptacle  
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 CertificationProgram-canbecertain  
thattheAHAMCertification Seal accurately states the unit’s cooling and heating capacity rating,  
the amperes and the energy efficiency ratio.  
7
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.  
Fan Motor Dual-shafted fan motor operates the indoor  
blower wheel and the condenser fan blade simultaneously.  
Vent door Allows introduction of fresh air into the room  
and/or exhausts stale room air outside (on select models.)  
Solenoid Used to energize the reversing valve on all heat  
pump units.  
Plenum assembly Diffuser with directional louvers used  
to direct the conditioned airflow.  
Heating element Electric resistance heater, available in 3.3,  
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.  
4.0 or 5.2 kW on select TwinTemp® models.  
Heat anticipator Used to provide better thermostat and  
room air temperature control.  
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.  
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.  
ELECTRICAL COMPONENTS  
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.  
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 troubleshoot-  
ing, refer to the wiring diagrams and schematics in the back  
of this service manual.  
Capillary tube A cylindrical meter device used to evenly dis-  
tribute 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  
PM  
CHECK FILTER light will come on after 250 hours of use.  
Touch CHECK FILTER to reset.  
Set Hour Check  
Clock  
72  
Filter  
Press to reset  
On/Off  
Money  
Saver  
Fan  
Only  
Cool  
Cooler  
Warmer  
0F/0C  
Smart  
Fan  
Speed  
1-4  
A/C  
Stop  
A/C  
Start  
Timer  
On/Off  
Electronic Control  
8
ELECTRONIC CONTROLS  
TESTING THE ELECTRONIC CONTROL  
XQ/WS BOARDS & QME BOARDS  
TESTING THE ELECTRONIC CONTROL  
ERROR CODE LISTINGS  
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.  
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.  
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.  
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.  
E4 FROST PROBE SHORT: Replace board.  
E5 INDOOR PROBE OPEN: Replace board.  
E6 INDOOR PROBE SHORT: 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.  
INDOOR PROBE SENSOR: Control range is 60° F to 90°  
F +/- 2° F.  
ActivatingErrorCodeMode:(Submode of Test Mode) Unit  
must be in Test Mode to enter Error Code Mode  
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.  
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.  
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.  
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.  
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.  
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.  
9
REFRIGERATION SYSTEM SEQUENCE OF OPERATION  
A good understanding of the basic operation of the refrigera-  
tion 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:  
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.  
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”  
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.  
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 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 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 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.  
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.  
Refrigerant System Components  
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.  
Suction  
Line  
Discharge  
Line  
Evaporator  
Coil  
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.  
Compressor  
Metering  
Refrigerant Drier  
Device  
Liquid  
Refrigerant  
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.  
Line  
Dryer  
SEALED REFRIGERATION SYSTEM REPAIRS  
IMPORTANT  
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.  
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.  
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.  
Since the evaporator coil is under a lower pressure (due to  
the suction created by the compressor) than the liquid line,  
10  
EQUIPMENT REQUIRED  
1. Voltmeter  
HERMETIC COMPONENT REPLACEMENT cont’d  
6. Pressurize system to 30 PSIG with proper refrigerant and  
boost refrigerant pressure to 150 PSIG with dry nitrogen.  
2. Ammeter  
7. Leak test complete system with electric halogen leak  
detector, correcting any leaks found.  
3. Ohmmeter  
4. E.P.A. Approved Refrigerant Recovery System.  
5. Vacuum Pump (capable of 200 microns or less vacuum.)  
6. Acetylene Welder  
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.)  
7. Electronic Halogen Leak Detector (G.E. Type H-6 or  
equivalent.)  
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.  
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)  
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%.  
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.  
2. Evacuation from both the high side and low side of the  
system simultaneously.  
3. Introducing refrigerant charge into high side of the  
system.  
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.  
4. Accurately weighing the refrigerant charge actually  
introduced into the system.  
5. Facilities for flowing nitrogen through refrigeration  
tubing during all brazing processes.  
SPECIALPROCEDUREINTHECASEOFCOMPRESSOR  
MOTOR BURNOUT  
HERMETIC COMPONENT REPLACEMENT  
1. Recover all refrigerant and oil from the system.  
The following procedure applies when replacing components  
in the sealed refrigeration circuit or repairing refrigerant  
leaks. (Compressor, condenser, evaporator, capillary tube,  
refrigerant leaks, etc.)  
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.  
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%.  
4. Reassemble the system, including new drier strainer  
and capillary tube.  
2. Cut the process tube below pinch off on the suction  
side of the compressor.  
5. Proceed with processing as outlined under hermetic  
component replacement.  
3. Connect the line from the nitrogen tank to the suction  
process tube.  
ROTARYCOMPRESSORSPECIAL TROUBLESHOOTING  
AND SERVICE  
Basically, troubleshooting and servicing rotary compressors  
is the same as on the reciprocating compressor with only  
one main exception:  
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.  
NEVER, under any circumstances, charge a rotary  
compressor through the LOW side. Doing so would  
cause permanent damage to the new compressor.  
11  
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.  
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.  
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.  
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:  
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.  
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.  
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.  
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.  
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  
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.  
12  
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.  
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.  
Whenever you service a unit with an undercharge of  
refrigerant, always suspect a leak. The leak must be repaired  
before charging the unit.  
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.  
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.  
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. Noncon-  
densables can also cause these symptoms. To confirm,  
remove some of the charge, if conditions improve, system  
may be overcharged. If conditions don’t improve, Noncon-  
densables are indicated.  
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.  
Whenever an overcharged system is indicated, alwaysmake  
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.  
13  
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.  
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.  
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 is no circulation of  
refrigerant in the system.  
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  
unitspecification. Withacompleterestrictionthecurrentdrawnmay  
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.  
• 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.  
14  
TROUBLESHOOTING TOUCH TEST CHART: TO SERVICE REVERSING VALVES  
NORMAL FUNCTION OF VALVE  
NOTES:  
VALVE  
OPERATING  
* TEMPERATURE OF VALVE BODY  
** WARMER THAN VALVE BODY  
CONDITION  
1
Hot  
2
Cool  
3
4
5
*TVB  
6
TVB  
POSSIBLE CAUSES  
CORRECTIONS  
Cool  
Hot  
Normal Cooling  
Normal Heating  
as (2)  
as (1)  
Hot  
as (1)  
Cool  
as (2)  
Hot  
Cool  
*TVB  
TVB  
MALFUNCTION OF VALVE  
No voltage to coil.  
Repair electrical circuit.  
Check Electrical circuit and coil  
Check refrigeration charge  
Defective coil.  
Replace coil.  
Low charge.  
Repair leak, recharge system.  
Recheck system.  
Pressure differential too high.  
Hot  
Cool  
Cool,  
as (2)  
Hot,  
as (1)  
*TVB  
Hot  
De-energize solenoid, raise head pres-  
sure, 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.  
Valve will not  
shift from cool  
to heat.  
Pilot valve okay. Dirt in one bleeder hole.  
Stop unit. After pressures equalize, restart  
with solenoid energized. If valve shifts,  
reattempt with compressor running. If still  
no shift, replace valve.  
Piston cup leak  
Cool,  
as (2)  
Hot,  
Raise head pressure, operate solenoid to  
free. If still no shift, replace valve.  
Hot  
Hot  
Cool  
Cool  
*TVB  
Hot  
*TVB  
Hot  
Clogged pilot tubes.  
as (1)  
Valve will not  
shift from cool  
to heat.  
Raise head pressure, operate solenoid to  
free partially clogged port. If still no shift,  
replace valve.  
Cool,  
as (2)  
Hot,  
as (1)  
Both ports of pilot open. (Back seat port did  
not close).  
Cool,  
as (2)  
Hot,  
Warm  
Hot  
Cool  
*TVB  
*TVB  
Warm Defective Compressor.  
Replace compressor  
as (1)  
Not enough pressure differential at start of  
Check unit for correct operating pressures  
and charge. Raise head pressure. If no  
shift, use valve with smaller port.  
Warm  
Warm  
Hot  
Hot  
stroke or not enough flow to maintain pres-  
sure differential.  
Body damage.  
Replace valve  
Starts to shift  
but does not  
complete  
Raise head pressure, operate solenoid.  
If no shift, use valve with smaller ports.  
Hot  
Hot  
Warm  
Hot  
Warm  
Hot  
Hot  
Hot  
Hot  
Hot  
Hot  
Both ports of pilot open.  
Body damage.  
*TVB  
Replace valve  
Valve hung up at mid-stroke. Pumping vol-  
ume of compressor not sufficient to maintain  
reversal.  
reversal.  
Raise head pressure, operate solenoid.  
If no shift, use valve with smaller ports.  
Raise head pressure, operate solenoid.  
If no shift, replace valve.  
Hot  
Hot  
Hot  
Hot  
Hot  
Hot  
Hot  
Both ports of pilot open.  
Hot,  
as (1)  
Cool,  
as (2)  
Operate valve several times, then recheck.  
If excessive leak, replace valve.  
Cool  
*TVB  
*TVB  
Piston needle on end of slide leaking.  
Apparent  
leap in heating.  
Hot,  
Cool,  
as (2)  
Operate valve several times, then recheck.  
If excessive leak, replace valve.  
Hot  
Hot  
Cool  
Cool  
** WVB ** WVB Pilot needle and piston needle leaking.  
as (1)  
Hot,  
as (1)  
Cool,  
as (2)  
Stop unit. Will reverse during equalization  
period. Recheck system  
*TVB  
*TVB  
Pressure differential too high.  
Clogged pilot tube.  
Raise head pressure, operate solenoid to  
free dirt. If still no shift, replace valve.  
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,  
Cool,  
as (2)  
Hot  
Hot  
Cool  
Cool  
Hot  
Hot  
*TVB  
*TVB  
Dirt in bleeder hole.  
Piston cup leak.  
as (1)  
Will not shift  
from heat to  
cool.  
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,  
as (1)  
Cool,  
as (2)  
Hot,  
Cool,  
as (2)  
Hot  
Cool  
Cool  
Hot  
Hot  
Defective pilot.  
Replace valve.  
as (1)  
Warm,  
as (1)  
Cool,  
as (2)  
Warm  
Warm  
*TVB  
Defective compressor.  
Replace compressor  
15  
COOLING ONLY ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS  
Problem  
Possible Cause  
Low voltage  
Action  
Check voltage at compressor. 115V & 230V  
units will operate at 10% voltage variance  
T-stat not set cold enough or inop- Set t-stat to coldest position. Test t-stat &  
erative  
replace if inoperative  
Compressor hums but cuts off on  
B10 overload  
Open or shorted compressor wind-  
ings  
Hard start compressor. Direct test compressor.  
If compressor starts, add starting components  
Compressor  
does not run  
Check for continuity & resistance  
Open overload  
Open capacitor  
Test overload protector & replace if inoperative  
Test capacitor & replace if inoperative  
Test for continuity in all positions. Replace if  
inoperative  
Inoperative system switch  
Refer to appropriate wiring diagrams to check  
wiring  
Broken, loose or incorrect wiring  
Problem  
Possible Cause  
Inoperative system switch  
Broken, loose or incorrect wiring  
Open capacitor  
Action  
Test switch & replace if inoperative  
Refer to applicable wiring diagram  
Test capacitor & replace if inoperative  
Test switch & replace if inoperative  
Fan motor  
does not run  
Fan speed switch open  
Test fan motor & replace if inoperative (be sure  
internal overload has had time to reset)  
Inoperative fan motor  
Problem  
Possible Cause  
Action  
Undersized unit  
Refer to industry standard sizing chart  
Set to coldest position. Test t-stat & replace if  
necessary  
Clean as recommended in Owner's Manual  
T-stat open or inoperative  
Dirty filter  
Dirty or restricted condenser or  
evaporator coil  
Poor air circulation  
Use pressure wash or biodegradable cleaning  
agent to clean  
Adjust discharge louvers. Use high fan speed  
Does not cool or  
only cools slightly  
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  
Check amperage draw against nameplate. If  
not conclusive, make pressure test  
Compressor not pumping properly  
16  
Problem  
Possible Cause  
Action  
Replace fuse, reset breaker. If repeats, check  
fuse or breaker size. Check for shorts in unit  
wiring & components  
Fuse blown or circuit tripped  
Power cord not plugged in  
System switch in "OFF" position  
Inoperative system switch  
Plug it in  
Set switch correctly  
Test for continuity in each switch position  
Unit does not run  
Loose or disconnected wiring at  
switch or other components  
Check wiring & connections. Reconnect per  
wiring diagram  
Problem  
Possible Cause  
Action  
Dirty filter  
Clean as recommended in Owner's Manual  
Check for dirty or obstructed coil. Use  
pressure wash or biodegradable cleaning  
agent to clean  
Restricted airflow  
Inoperative t-stat  
Short of refrigerant  
Inoperative fan motor  
Test for shorted t-stat or stuck contacts  
De-ice coil & check for leak  
Test fan motor & replace if inoperative  
Evaporator coil  
freezes up  
De-ice coil. Check temp. differential (delta T)  
across coil. Touch test coil return bends for  
same temp. Test for low running current  
Partially restricted capillary tube  
Problem  
Possible Cause  
Action  
Unit undersized. Test cooling performance &  
replace with larger unit if needed  
Excessive heat load  
Check for partially iced coil & check  
temperature split across coil  
Check for oil at silver soldered connections.  
Check for partially iced coil. Check split across  
coil. Check for low running amperage  
Restriction in line  
Refrigerant leak  
Compressor runs  
continually & does  
not cycle off  
Check operation of t-stat. Replace if contacts  
remain closed.  
Refer to appropriate wiring diagram  
T-stat contacts stuck  
T-stat incorrectly wired  
Problem  
Possible Cause  
Action  
Disconnect power to unit. Remove cover  
of t-stat & check if contacts are stuck. If so,  
replace t-stat  
T-stat contacts stuck  
Turn to higher temp. setting to see if unit  
cycles off  
Refer to appropriate wiring diagrams  
T-stat does not turn  
unit off  
T-stat set at coldest point  
Incorrect wiring  
Unit undersized for area to be  
cooled  
Refer to industry standard sizing chart  
17  
Problem  
Possible Cause  
Action  
Overload inoperative. Opens too  
soon  
Check operation of unit. Replace overload if  
system operation is satisfactory  
Allow a minimum of 2 minutes to allow  
pressures to equalize before attempting to  
restart. Instruct customer of waiting period  
Compressor restarted before  
system pressures equalized  
Check voltage with unit operating. Check for  
other appliances on circuit. Air conditioner  
should be in separate circuit for proper voltage  
& fused separately  
Compressor runs  
for short periods  
only. Cycles on  
overload  
Low or fluctuating voltage  
Incorrect wiring  
Refer to appropriate wiring diagram  
Check by substituting a known good capacitor  
of correct rating  
Shorted or incorrect capacitor  
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  
Possible Cause  
Action  
Place jumper across t-stat terminals to check if  
unit operates. If unit operates, replace t-stat.  
Check as above  
Loss of charge in t-stat bulb  
T-stat does not  
turn unit on  
Loose or broken parts in t-stat  
Incorrect wiring  
Refer to appropriate wiring diagram  
Problem  
Possible Cause  
Poorly installed  
Action  
Refer to Installation Manual for proper  
installation  
Fan blade striking chassis  
Reposition - adjust motor mount  
Check that compressor grommets have not  
deteriorated. Check that compressor mounting  
parts are not missing  
Noisy operation  
Compressor vibrating  
Improperly mounted or loose  
cabinet parts  
Check assembly & parts for looseness,  
rubbing & rattling  
Problem  
Possible Cause  
Action  
Evaporator drain pan overflowing  
Clean obstructed drain trough  
Evaporator drain pan broken or cracked.  
Reseal or replace  
Condensation forming on base pan  
Poor installation resulting in rain  
entering the room  
Condensation on discharge grille  
louvers  
Check installation instructions. Reseal as  
required  
Clean the dirty evaporator coil. Use pressure  
wash or biodegradable cleaning agent to clean  
Water leaks into  
the room  
Chassis gasket not installed  
Install gasket, per Installation manual  
Downward slope of unit is too  
steep  
Refer to installation manual for proper  
installation  
18  
Problem  
Possible Cause  
Sublimation:  
When unconditioned saturated,  
outside air mixes with conditioned  
air, condensation forms on the  
cooler surfaces  
Action  
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  
Water "spitting"  
into room  
Follow installation instructions to ensure that  
downward pitch of installed unit is no less than  
1/4" & no more than 3/8"  
Downward pitch of installation is  
too steep  
Clean & advise customer of periodic cleaning  
& maintenance needs of entire unit  
Restricted coil or dirty filter  
Problem  
Possible Cause  
Action  
Insufficient air circulation thru area  
to be air conditioned  
Oversized unit  
Adjust louvers for best possible air circulation  
Operate in "MoneySaver" position  
Excessive moisture  
Inadequate vapor barrier in  
building structure, particularly  
floors  
Advise customer  
Problem  
Possible Cause  
Action  
T-stat differential too narrow  
Replace t-stat  
Plenum gasket not sealing,  
allowing discharge air to short  
cycle t-stat  
Check gasket. Reposition or replace as  
needed  
T-stat short cycles  
Clean & advise customer of periodic cleaning  
& maintenance needs of entire unit  
Restricted coil or dirty filter  
Problem  
Possible Cause  
Action  
Anticipator (resistor) wire  
disconnected at t-stat or system  
switch  
Refer to appropriate wiring diagram  
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  
Prolonged off  
cycles (automatic Anticipator (resistor) shorted or  
operation)  
open  
Partial loss of charge in t-stat bulb  
causing a wide differential  
Replace t-stat  
Problem  
Possible Cause  
Action  
Evaporator drain pan cracked or  
obstructed  
Repair, clean or replace as required  
Detach shroud from pan & coil. Clean &  
Water in compressor area  
Obstructed condenser coil  
remove old sealer. Reseal, reinstall & check  
Outside water  
leaks  
Use pressure wash or biodegradable cleaning  
agent to clean  
Fan blade/slinger ring improperly  
positioned  
Adjust fan blade to 1/2" of condenser coil  
19  
HEAT / COOL ROOM AIR CONDITIONERS: TROUBLESHOOTING TIPS  
Problem  
Possible Cause  
Action  
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  
Heat anticipator (resistor) shorted  
(on applicable models)  
Room temperature  
uneven  
(Heating cycle)  
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  
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  
If outside coil temperature is 25F or below, &  
preselected time limit has elapsed, replace  
defrost control  
If contacts remain closed between terminals  
"2" & "3" of the defrost control after  
preselected time interval has passed, replace  
control  
Defrost control out of calibration  
(applicable models)  
Unit will not defrost  
Defrost control contacts stuck  
Defrost control bulb removed from Reinstall & be assured that good bulb to coil  
or not making good coil contact  
contact is made  
Problem  
Possible Cause  
Exhaust or fresh air door open  
Dirty filter  
Action  
Check if operating properly. Instruct customer  
on proper use of control  
Clean as recommended in Owner's Manual  
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  
T-stat should close at 38°F. Check continuity of  
control. If temperature is below 38°F, replace  
control  
Unit undersized  
Does not heat  
adequately  
Outdoor t-stat open (applicable  
models)  
Check for adequate fan air across heater.  
Check control for open at 160°F & close at  
150°F  
Heater hi-limit control cycling on &  
off  
Shorted supplementary heater  
Incorrect wiring  
Ohmmeter check, approx. 32-35 ohms  
Check applicable wiring diagram  
20  
Problem  
Possible Cause  
Incorrect wiring  
Action  
Refer to applicable wiring diagram  
Check for continuity of coil  
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.  
Defective solenoid coil  
Reversing valve fails to shift  
Inoperative system switch  
Possible Cause  
Unit cools when  
heat is called for  
Check for continuity of system switch  
Problem  
Action  
Heating capillary tube partially  
restricted  
Check for partially starved outer coil. Replace  
heating capillary tube  
Switch unit several times from heating to  
cooling. Check temperature rise across  
coil. Refer to specification sheet for correct  
temperature rise  
De-energize solenoid coil, raise head  
pressure, energize solenoid to break loose.  
If valve fails to make complete shift, replace  
valve.  
Cooling adequate, Check valve leaking internally  
but heating  
insufficient  
Reversing valve failing to shift  
completely; bypassing hot gas  
TROUBLESHOOTING CHART — COOLING  
REFRIGERANT SYSTEM DIAGNOSIS – HEATING  
Low Suction Pressure  
Low Load Conditions  
High Suction Pressure  
High Load Conditions  
Low Head Pressure  
Low Load Conditions  
High Head Pressure  
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  
in System  
Undercharged  
Overcharged  
Noncondensables (air)  
Moisture in System  
Defective Compressor  
Defective Compressor  
21  
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  
Is the Selector Switch  
Set for Heat?  
Present at the Solenoid  
NO  
NO  
YES  
Is the Solenoid Coil Good?  
YES  
Replace the Solenoid Coil  
Reversing Valve Stuck  
Replace the Reversing Valve  
22  
MODEL  
SC06H10D  
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  
RAC-Svc-06 (3-06)  
Printed in the U.S.A.  

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