Rheem air conditioner troubleshooting

Even reliable air conditioners Rheem can break down as any other complex appliances. At the same time in the initial stage the cause of a breakdown of them must be revealed and only then one must refer to a service center. Rheem air conditioner troubleshooting system is serving precisely for this purpose.

Unit will not run• Power off or loose electrical connection
• Thermostat out of calibration-set too high
• Defective contactor
• Blown fuses / tripped breaker
• Transformer defective
• High pressure control open (if provided)
• Check for correct voltage at contactor in condensing unit
• Reset
• Check for 24 volts at contactor coil - replace if contacts are
• Replace fuses / reset breaker
• Check wiring-replace transformer
• Reset-also see high head pressure remedy-The high pressure
control opens at 450 PSIG
Outdoor fan runs, compressor
• Run or start capacitor defective
• Start relay defective
• Loose connection
• Compressor stuck, grounded or open motor winding,
open internal overload.
• Low voltage condition
• Replace
• Replace
• Check for correct voltage at compressor -
check & tighten all connections
• Wait at least 2 hours for overload to reset.
If still open, replace the compressor.
• Add start kit components
Insufficient cooling• Improperly sized unit
• Improper indoor airflow
• Incorrect refrigerant charge
• Air, non-condensibles or moisture in system
• Recalculate load
• Check - should be approximately 400 CFM per ton.
• Charge per procedure attached to unit service panel
• Recover refrigerant, evacuate & recharge, add filter drier
Compressor short cycles• Incorrect voltage
• Defective overload protector
• Refrigerant undercharge
• At compressor terminals, voltage must be ± 10% of
nameplate marking when unit is operating.
• Replace - check for correct voltage
• Add refrigerant
Registers sweat• Low indoor airflow• Increase speed of blower or reduce restriction - replace air
High head-low vapor pressures• Restriction in liquid line, expansion device or filter drier
• Flowcheck piston size too small
• Incorrect capillary tubes
• Remove or replace defective component
• Change to correct size piston
• Change coil assembly
High head-high or normal vapor
pressure - Cooling mode
• Dirty outdoor coil
• Refrigerant overcharge
• Outdoor fan not running
• Air or non-condensibles in system
• Clean coil
• Correct system charge
• Repair or replace
• Recover refrigerant, evacuate & recharge
Low head-high vapor pressures• Flowcheck piston size too large
• Defective Compressor valves
• Incorrect capillary tubes
• Change to correct size piston
• Replace compressor
• Replace coil assembly
Low vapor - cool compressor -
iced indoor coil
• Low indoor airflow
• Operating below 65°F outdoors
• Moisture in system
• Increase speed of blower or reduce restriction - replace air
• Add Low Ambient Kit
• Recover refrigerant - evacuate & recharge - add filter drier
High vapor pressure• Excessive load
• Defective compressor
• Recheck load calculation
• Replace
Fluctuating head & vapor
• TXV hunting
• Air or non-condensibles in system
• Check TXV bulb clamp - check air distribution on coil - replace
• Recover refrigerant, evacuate & recharge
Gurgle or pulsing noise at
expansion device or liquid line
• Air or non-condensibles in system• Recover refrigerant, evacuate & recharge
Compressor runs, ECM
outdoor fan doesn't
• 24VAC signal not present at yellow fan wire
• Common signal not present at blue fan wire
• Check for correct thermostat connections
• Verify blue fan wire is connected to the common side

Rheem air conditioner troubleshooting

Status and Diagnostic Description

7 -Segment
Display Code
Diagnostic DescriptionStatus / Possible Cause -Troubleshooting
0StandbyStandby - No call for operation
cY1First Stage or Single Stage Unit Operation
CY2Second stage unit operation
(2-stage unit only)
c or
C Flashing
Anti-Short Cycle Timer (3 minutes) or
Minimum Run Timer (30 seconds)
Waiting for anti-short cycle timer to expire
Waiting for minimum run timer to expire
FICC Board Fuse Open1. Low voltage wiring damage or miswired
1 (*)Compressor Running Extremely Long Run
Cycle (Cooling mode only)
1. Low refrigerant charge
2. Air ducts have substantial leakage
3. Check thermostat operation
4. Dirty filter
5. Dirty outdoor coil
2 (*)Pressure Control Trip (L terminal output only)1. (See faults 21, L21, 23, L23)
21 (***)Low Pressure Control Trip
Note: Low-pressure control is ignored for 90
seconds after call for unit operation.
Active Protection – The ICC will try to
restart the unit after the pressure control
automatically re-closes.
Unit will try to restart 3 times in the same
thermostat call for operation (Y1) before
lockout (fault L21)
1. Unit is low on refrigerant charge
2. Indoor coil is frozen (cooling mode)
3. Dirty indoor coil or filter (cooling mode)
4. Indoor blower is not running (cooling mode)
5. TEV is not operating correctly
L21 (**)Lockout - Low Pressure Control Trip (**)LPC tripped three consecutive times in same
thermostat call
23 (***)High Pressure Control Trip
Active Protection – The ICC will try to
restart the unit after the pressure control
automatically re-closes.
Unit will try to restart 3 times in the same
thermostat call for operation (Y1) before
lockout (fault L23)
1. Outdoor coil is dirty (cooling mode)
2. Outdoor fan is not running (cooling mode)
3. Dirty indoor coil or filter (heat pump mode)
4. Liquid line restriction (filter drier blocked, etc.)
5. Excessive refrigerant charge
L23 (**)Lockout - High Pressure Control Trip (**)HPC tripped three consecutive times in same
thermostat call
25Outdoor Ambient Temperature Sensor1. ICC board sensor damaged (ICC
will continue to operate)
27Abnormal Low Line or No Line Voltage
(See unit nameplate for operating voltage)
1. Check incoming line voltage to the disconnect
and unit
2. Check wiring connections
28Abnormal High Line Voltage1. Check line voltage
3 (*)Short Cycling1. Check thermostat for intermittent demand
2. Check thermostat location in zone (too close to
discharge grill)
5 (*) (***)Compressor will not run
Active Protection – After detecting compressor
will not run the ICC control will shut the unit
down. The control will try to restart the unit
every 5 minutes for 4 tries. After that, the ICC
will attempt a restart every 20 minutes up to 6
1. Check for damaged, miswired, or wrong run
2. Check for damaged or miswired start capacitor
and relay
3. Check voltage levels at ICC board and
4. Check for broken wires, loose connectors, or
5. Check compressor motor windings for
6. Check for open compressor internal protector
7. Check for excessive liquid refrigerant in
L5 (**)Lockout – Check Compressor (**)After 6 hours of attempted unit restart ICC control
-ICC Board Mis-operation1. Check ICC board compressor relay
8 (*)ICC Board Mis-operation (L terminal
output only)
1. Check ICC board compressor relay
9 (*)ICC Secondary Voltage Low
(Less than 18V)
1. Check transformer for miswiring or

(*) – Indicates flash code will be an output on the ICC “L” terminal to the indoor
thermostat “L” terminal. Unless a diagnostic/fault is manually cleared by cycling
power or pressing the TEST button the flash code will continue at the L terminal for
up to 20 seconds after the start of a successful call for unit operation.
L Terminal Output
• Flash 1 – Compressor running extremely long run cycle
• Flash 2 – Low or High pressure control trip
• Flash 3 – Unit short cycling
• Flash 5 – Compressor will not run
• Flash 8 – Control mis-operation
• Flash 9 – Low control voltage
(**) – Lockout modes are reset by either cycling line voltage, low voltage, or by
pressing control TEST button for 1 second. The control will attempt to start the unit
when the TEST button is pressed and released.
(***) – Caution: Indicates Active Protection. Unit will attempt to restart auto-