Rheem Furnaces Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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Symptom
Furnace has power but does not start any heating cycle; status LED shows solid ON or steady 0 code
Normal Standby / No Call for Heat
1
Status LED flashes 1 time repeatedly; furnace will not start heating cycle
Ignition Failure / Lockout (generic single-flash code on some Rheem boards)
10
Status LED flashes 10 times; furnace may not respond to thermostat
Reversed Line Polarity or Grounding Issue
11
Status LED flashes 11 times; furnace may not start or may behave erratically
Internal Control Board Fault
12
Status LED flashes 12 times; furnace may intermittently fail to start
Low 24V Control Voltage
13
Status LED flashes 13 times; furnace may lock out after repeated limit trips
Limit Circuit Lockout
14
Status LED flashes 14 times; furnace may not respond to thermostat or may short-cycle
Thermostat Lockout / Miswire
2
Status LED flashes 2 times repeatedly; furnace will not fire or shuts down quickly
Pressure Switch Stuck Closed
3
Status LED flashes 3 times; furnace starts but shuts down before or shortly after ignition
Pressure Switch Stuck Open
31
Status LED flashes 3 short and 1 long (31); furnace may not start or may shut down early
Pressure Switch Did Not Close or Reopen
33
Status LED flashes 3 short and 3 long (33); furnace may run blower only
Limit or Flame Rollout Switch Open
34
Status LED flashes 3 short and 4 long (34); furnace lights but may shut off quickly
Ignition Proving Failure
4
Status LED flashes 4 times; furnace attempts to start but burners do not light or shut off quickly
Open High Limit Switch
41
Status LED flashes 4 short and 1 long (41); furnace may overheat or underheat
Blower Motor Fault / Incorrect Blower Operation
42
Status LED flashes 4 short and 2 long (42); furnace may not start heating cycle
Inducer Motor Fault
43
Status LED flashes 4 short and 3 long (43); furnace may short-cycle or not respond correctly
Pressure Switch Calibration or Airflow Fault
44
Status LED flashes 4 short and 4 long (44); furnace may not ignite or may lock out
Ignition Lockout – Excessive Retries
5
Status LED flashes 5 times; furnace shuts down and may lock out after several attempts
Flame Sensed with Gas Valve Off / False Flame Signal
6
Status LED flashes 6 times; furnace may run blower only or shut down
Rollout Switch Open / Flame Rollout Detected
7
Status LED flashes 7 times; furnace may start then shut down, or not start at all
Low Flame Sense / Flame Loss
8
Status LED flashes 8 times; furnace may run inducer but not ignite
Ignition Lockout Due to Repeated Failures
9
Status LED flashes 9 times; furnace may run blower continuously without heat
High Limit or Auxiliary Limit Lockout
Symptom
Burners light but go out after a few seconds; furnace retries several times then stops
Flame Sensing Failure
Symptom
Furnace blower runs continuously even when there is no call for heat or fan
Blower Stuck in Fan-On Mode
Symptom
Furnace causes noticeable vibration and rumbling transmitted through the house
Mechanical Vibration from Blower or Inducer
Symptom
Furnace emits a rotten egg or sulfur smell when running
Possible Gas Leak or Incomplete Combustion
Symptom
Furnace frequently trips the household circuit breaker
Overcurrent or Electrical Short in Furnace
Symptom
Furnace makes loud booming or banging noise at burner ignition
Delayed Ignition
Symptom
Furnace or ductwork makes loud banging or popping noises when starting or stopping
Duct Expansion/Contraction and Airflow Imbalance
Symptom
Furnace produces a high-pitched squealing or screeching noise during operation
Blower or Inducer Bearing Wear
Symptom
Furnace runs but does not produce any warm air; blower is on, air from vents is cool
No Heat Production with Blower Operation
Symptom
Furnace runs but some rooms are too cold while others are too warm
Air Distribution Imbalance
Symptom
Furnace runs continuously and overshoots the thermostat set temperature
Thermostat or Control Stuck in Heat Call
Symptom
Furnace short cycles: starts, heats briefly, then shuts off and restarts frequently
Short Cycling Due to Overheating or Flame Loss
Symptom
Furnace starts normally but shuts off before reaching set temperature; thermostat still calling for heat
Premature Limit Trip or Overheating
Symptom
Furnace will not start at all; no blower, no inducer, no LED lights
No Power to Furnace
Symptom
Inducer motor runs but burners never light; furnace keeps trying and stopping
Ignition Sequence Failure
Symptom
Rust stains or water inside burner compartment of high-efficiency furnace
Condensate Backflow into Heat Exchanger or Collector Box
Symptom
Strong burning or electrical smell when furnace runs
Overheating Components or Dust Burn-Off
Symptom
Thermostat goes blank or resets when furnace starts
Low Voltage Drop or Short During Furnace Operation
Symptom
Water leaking around the base of a high-efficiency Rheem furnace
Condensate Drain Leak or Blockage
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| – |
Furnace has power but does not start any heating cycle; status LED shows solid ON or steady 0 code
|
Normal Standby / No Call for Heat | View Details |
| 1 |
Status LED flashes 1 time repeatedly; furnace will not start heating cycle
|
Ignition Failure / Lockout (generic single-flash code on some Rheem boards) | View Details |
| 10 |
Status LED flashes 10 times; furnace may not respond to thermostat
|
Reversed Line Polarity or Grounding Issue | View Details |
| 11 |
Status LED flashes 11 times; furnace may not start or may behave erratically
|
Internal Control Board Fault | View Details |
| 12 |
Status LED flashes 12 times; furnace may intermittently fail to start
|
Low 24V Control Voltage | View Details |
| 13 |
Status LED flashes 13 times; furnace may lock out after repeated limit trips
|
Limit Circuit Lockout | View Details |
| 14 |
Status LED flashes 14 times; furnace may not respond to thermostat or may short-cycle
|
Thermostat Lockout / Miswire | View Details |
| 2 |
Status LED flashes 2 times repeatedly; furnace will not fire or shuts down quickly
|
Pressure Switch Stuck Closed | View Details |
| 3 |
Status LED flashes 3 times; furnace starts but shuts down before or shortly after ignition
|
Pressure Switch Stuck Open | View Details |
| 31 |
Status LED flashes 3 short and 1 long (31); furnace may not start or may shut down early
|
Pressure Switch Did Not Close or Reopen | View Details |
| 33 |
Status LED flashes 3 short and 3 long (33); furnace may run blower only
|
Limit or Flame Rollout Switch Open | View Details |
| 34 |
Status LED flashes 3 short and 4 long (34); furnace lights but may shut off quickly
|
Ignition Proving Failure | View Details |
| 4 |
Status LED flashes 4 times; furnace attempts to start but burners do not light or shut off quickly
|
Open High Limit Switch | View Details |
| 41 |
Status LED flashes 4 short and 1 long (41); furnace may overheat or underheat
|
Blower Motor Fault / Incorrect Blower Operation | View Details |
| 42 |
Status LED flashes 4 short and 2 long (42); furnace may not start heating cycle
|
Inducer Motor Fault | View Details |
| 43 |
Status LED flashes 4 short and 3 long (43); furnace may short-cycle or not respond correctly
|
Pressure Switch Calibration or Airflow Fault | View Details |
| 44 |
Status LED flashes 4 short and 4 long (44); furnace may not ignite or may lock out
|
Ignition Lockout – Excessive Retries | View Details |
| 5 |
Status LED flashes 5 times; furnace shuts down and may lock out after several attempts
|
Flame Sensed with Gas Valve Off / False Flame Signal | View Details |
| 6 |
Status LED flashes 6 times; furnace may run blower only or shut down
|
Rollout Switch Open / Flame Rollout Detected | View Details |
| 7 |
Status LED flashes 7 times; furnace may start then shut down, or not start at all
|
Low Flame Sense / Flame Loss | View Details |
| 8 |
Status LED flashes 8 times; furnace may run inducer but not ignite
|
Ignition Lockout Due to Repeated Failures | View Details |
| 9 |
Status LED flashes 9 times; furnace may run blower continuously without heat
|
High Limit or Auxiliary Limit Lockout | View Details |
| – |
Burners light but go out after a few seconds; furnace retries several times then stops
|
Flame Sensing Failure | View Details |
| – |
Furnace blower runs continuously even when there is no call for heat or fan
|
Blower Stuck in Fan-On Mode | View Details |
| – |
Furnace causes noticeable vibration and rumbling transmitted through the house
|
Mechanical Vibration from Blower or Inducer | View Details |
| – |
Furnace emits a rotten egg or sulfur smell when running
|
Possible Gas Leak or Incomplete Combustion | View Details |
| – |
Furnace frequently trips the household circuit breaker
|
Overcurrent or Electrical Short in Furnace | View Details |
| – |
Furnace makes loud booming or banging noise at burner ignition
|
Delayed Ignition | View Details |
| – |
Furnace or ductwork makes loud banging or popping noises when starting or stopping
|
Duct Expansion/Contraction and Airflow Imbalance | View Details |
| – |
Furnace produces a high-pitched squealing or screeching noise during operation
|
Blower or Inducer Bearing Wear | View Details |
| – |
Furnace runs but does not produce any warm air; blower is on, air from vents is cool
|
No Heat Production with Blower Operation | View Details |
| – |
Furnace runs but some rooms are too cold while others are too warm
|
Air Distribution Imbalance | View Details |
| – |
Furnace runs continuously and overshoots the thermostat set temperature
|
Thermostat or Control Stuck in Heat Call | View Details |
| – |
Furnace short cycles: starts, heats briefly, then shuts off and restarts frequently
|
Short Cycling Due to Overheating or Flame Loss | View Details |
| – |
Furnace starts normally but shuts off before reaching set temperature; thermostat still calling for heat
|
Premature Limit Trip or Overheating | View Details |
| – |
Furnace will not start at all; no blower, no inducer, no LED lights
|
No Power to Furnace | View Details |
| – |
Inducer motor runs but burners never light; furnace keeps trying and stopping
|
Ignition Sequence Failure | View Details |
| – |
Rust stains or water inside burner compartment of high-efficiency furnace
|
Condensate Backflow into Heat Exchanger or Collector Box | View Details |
| – |
Strong burning or electrical smell when furnace runs
|
Overheating Components or Dust Burn-Off | View Details |
| – |
Thermostat goes blank or resets when furnace starts
|
Low Voltage Drop or Short During Furnace Operation | View Details |
| – |
Water leaking around the base of a high-efficiency Rheem furnace
|
Condensate Drain Leak or Blockage | View Details |
No matching codes found
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