What it means
One-hour lockout, caused by repeated failed ignition (11), water sensed (59), dead blower (61), internal fault (93), flame lost 5 times (13) or unexpected flame (14).
⚠ Call a profurnace
How it shows: Dual 7-segment display: 10 (alternates with the fault that caused it)
1Likely causes
- See the code shown alternately with 10
2Safe DIY steps
- Read the second code that alternates with 10 and follow that code
- Lockout clears when the cause is corrected and power is cycled off and on
⚠ Safety firstIf you smell gas, do not touch any electrical switch or use a phone in the building; leave immediately and call your gas supplier from outside. Turn off electrical power at the furnace switch or breaker before opening any panel, and never bypass or jumper a limit, rollout or pressure switch. Gas valve, burner, venting, wiring and control-board work should be done by a licensed HVAC technician.
3When to call a pro
Call a licensed HVAC technician: if the furnace keeps entering lockout.
Find a local HVAC pro →Other Rheem codes
12
Low flame sense: flame sense current is weak or marginal. Furnace keeps running.
11
Failed ignition. After four failed attempts the control enters one-hour lockout (10).
13
Flame lost after established.
14
Flame present with gas valve off. Extremely critical; furnace will not operate.
30
Open fuse, usually from a 24 VAC short to common or ground.
33
Over-temperature (rollout) switch open: flames rolled out of the heat exchanger into the burner compartment.