Rheem Error Codes | HVAC IQ Pro

1 info

Heating Operational

Probable Causes

Normal operation

Diagnostic Steps

No action needed

1 Flash critical

Flame Without Gas Valve Energized

Probable Causes

Sticking gas valve
Short in flame sensor circuit

Diagnostic Steps

STOP - shut off gas
Test gas valve operation
Check flame sensor wiring

2 critical

External Limit Fault

Probable Causes

Limit switch open
Rollout switch open
Auxiliary limit

Diagnostic Steps

Check limit switches
Check airflow
Reset and observe

2 Flash high

Pressure Switch Stuck Closed

Probable Causes

Bad pressure switch
Inducer running when shouldn't be

Diagnostic Steps

Test pressure switch normally open
Check inducer operation
Replace switch if stuck

3 critical

Pressure Switch Fault

Probable Causes

Blocked vent
Bad inducer
Cracked heat exchanger

Diagnostic Steps

Inspect flue
Check inducer
Test pressure switch

3 Flash high

Pressure Switch Stuck Open

Probable Causes

Blocked vent
Bad hose
Weak inducer
Condensate blockage

Diagnostic Steps

Check flue/intake
Inspect hose to switch
Test inducer amps
Clear condensate

4 warning

Flame Sense Fault

Probable Causes

Dirty flame sensor
Bad ground
Weak flame

Diagnostic Steps

Clean flame sensor
Check grounding
Check gas pressure

4 Flash high

Open High Limit

Probable Causes

Dirty filter
Blocked returns
Bad blower
Oversized gas orifice

Diagnostic Steps

Replace filter
Check returns
Test blower
Check gas pressure

5 critical

Ignition Fault

Probable Causes

Bad igniter
No gas
Control board issue

Diagnostic Steps

Test igniter
Verify gas
Check board

5 Flash critical

Flame Rollout Switch Open

Probable Causes

Heat exchanger crack
Blocked HX
Gas overpressure

Diagnostic Steps

STOP - CO hazard
Inspect heat exchanger
Test CO levels
Check gas pressure

6 Flash critical

Ignition Failure

Probable Causes

Weak/broken igniter
No gas
Dirty flame sensor

Diagnostic Steps

Verify gas supply
Check igniter resistance (40-200 ohms)
Clean flame sensor
Check grounding

7 Flash critical

Ignition Lockout - Max Retries

Probable Causes

Repeated ignition failures

Diagnostic Steps

Power cycle to clear lockout
Address underlying issue from code 6
Service call needed

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