Rheem Error Code C: Cooling or heat-pump heat (compressor call) (Furnace)

Updated October 15, 2026 · by Aurora Star Tech Inc.

Rheem error code C on a furnace means: Cooling or heat-pump heat (compressor call). It is also called Rheem diagnostic code C.

Low severityFurnaceRheem/Ruud 802P / 80MDP 80% two-stage furnace (UT 1028-928 IFC) · R95P · RGPE/RGLE · R96V/96MDV

Homeowner? What Rheem code C means for you

Usually minor Your furnace is reporting: Cooling or heat-pump heat (compressor call). This code is usually informational or minor. The safe checks below often clear it; call us if it keeps showing up.

Safe things you can check yourself

Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
Make sure the furnace front door or panel is closed properly; many furnaces will not run with the door switch open.
Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
Check that the gas valve next to the furnace is open (handle in line with the pipe). Do not force it.
Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977 Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Rheem error code C mean?

A steady C on the seven-segment display means the furnace control sees a cooling or heat-pump heating call and is running the blower for it. Normal. If a lockout is active the lockout fault code is shown in place of the C. On RGPE/RGLE the cooling readout is c or C; with a communicating condenser a capital C is shown for both low and high cooling stage.

Applies to: Rheem/Ruud (-)802P / 80MDP 80% two-stage furnaces; R95P; Rheem/Ruud RGPE / RGLE modulating furnaces

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Rheem models that use code C

Show all 33 models

96MDV040B30A 96MDV060B30A 96MDV070B30A 96MDV085C50A 96MDV100C50A 96MDV115D50A R95PA0401317MSA R95PA0601317MSA R95PA0701317MSA R95PA0851521MSA R95PA1001521MSA R95PA1151524MSA R96VA0401317MSA R96VA0601317MSA R96VA0701317MSA R96VA0851521MSA R96VA1001521MSA R96VA1151524MSA R802PA050314MSA R802PA075417MSA R802PA100521MSA R802PA125524MSA R802PA150524MSA RGLE-05(-)BMKR RGLE-07(-)AMKR RGLE-07(-)BRQR RGLE-10(-)BRMR RGLE-12(-)ARMR RGPE-05(-)BMKR RGPE-07(-)AMKR RGPE-07(-)BRQR RGPE-10(-)BRMR RGPE-12(-)ARMR

Other Rheem Furnace codes

Code	Meaning
82	Supply air sensor fault (SA SENSOR FLT)
84	Outdoor air sensor fault
93	Internal control fault
AF	Airflow readout (pushbutton status menu)
Blank thermostat text area	Thermostat text area blank - system found OK
Blinking decimal point	Airflow readout - blinks of right decimal point
cd / Cd	Dehumidification cooling
CFM LED blinks	CFM LED blink count = target airflow
d1	No shared data (NO SHARED DATA)
d4	Memory card invalid (MEM CARD INVALD)
d5	Card/hardware conflict (CARD-HRD CNFLCT)
d6	Blower HP conflict (BLWR HP CNFLCT)

All Rheem Furnace error codes →

Rheem code C: homeowner questions

What does Rheem code C mean?

Cooling or heat-pump heat (compressor call). A steady C on the seven-segment display means the furnace control sees a cooling or heat-pump heating call and is running the blower for it. Normal. If a lockout is active the lockout fault code is shown in place of the C. On RGPE/RGLE…

Is it safe to keep using my furnace with code C?

Usually yes. Code C is normally minor, but if it keeps coming back have it checked.

Can I reset Rheem code C myself?

You can try one reset (power off for 30 seconds, then on). If Rheem code C comes back, the cause is still there and a licensed technician should check it.

Who can fix Rheem code C near me?

Aurora Star Tech Inc. repairs Rheem furnaces in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: Furnace Not Turning On: What to Check · Furnace Blinking Light: What the Flash Codes Mean

Troubleshooting guides

Blowing cold air All brands · Furnace
No heat All brands · Furnace
Short cycling All brands · Furnace
Blower codes 66, 61 and 60 - what to look for Rheem · Furnace
Blower does not start after burners light Rheem · Furnace
Burners go out before the heat call ends / short cycling Rheem · Furnace
Clear the fault history Rheem · Furnace
Clearing lockouts Rheem · Furnace
Codes look upside down - display orientation switch S1-1 Rheem · Furnace
Communicating system not found / no communication Rheem · Furnace
ECM blower does not start on heat Rheem · Furnace
ECM blower will not run - power and communication checks (code 68) Rheem · Furnace
Extended display mode Rheem · Furnace
Force low or high fire for testing (RGPE/RGLE) Rheem · Furnace
Furnace no heat - sequence troubleshooting Rheem · Furnace
Furnace short cycles or does not hold setpoint Rheem · Furnace
Gas valve does not shut off when heat call ends Rheem · Furnace
Heat call troubleshooting walk-through (two-stage communicating IFC) Rheem · Furnace
Indoor blower does not start after burners light Rheem · Furnace
Inducer (draft motor) does not start on heat call Rheem · Furnace
Inducer does not run / does not run on low speed Rheem · Furnace
Inducer runs 60 s then shuts off for 5 minutes, or runs continuously Rheem · Furnace
Inducer runs 60 seconds then off for 5 minutes Rheem · Furnace
No heat - inducer (IDM) does not start Rheem · Furnace
No heat - POWER LED off Rheem · Furnace
Pushbutton status menu: fault history, CFM, fire rate, unit size, temperature rise Rheem · Furnace
Read or clear the six-fault history from the thermostat (RGPE/RGLE) Rheem · Furnace
Read target airflow from the CFM LED Rheem · Furnace
Replacing the furnace control: keep the memory card and copy the dipswitches Rheem · Furnace
Replay or clear the fault history on power-up (802P / 80MDP / R95P) Rheem · Furnace
Replay or clear the last five faults (RGPE/RGLE) Rheem · Furnace
Reset a soft lockout (R95P) Rheem · Furnace
Single-stage thermostat on a two-stage furnace: auto staging Rheem · Furnace
Test communication with the LEARN button (RGPE/RGLE) Rheem · Furnace
Thermostat does not hold room temperature Rheem · Furnace

Source: Rheem (-)802PA Installation Instructions, Diagnostics and Fault Codes (UT 1028-928 control), pp.40-41; R95P pp.87-89; RGPE Dual Seven-Segment Diagnostic Display / Communicating Systems (pp.49-50). Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.