High pressure switch open with inducer on high speed; furnace may drop to low fire.
§1Likely causes
- Blocked or improperly terminated vents
- Vent length or elbows exceed maximum
- Faulty or disconnected inducer
- Faulty control board
- High altitude kit not installed
- Loose or faulty wiring
- Damaged pressure switch hoses
- Wind gusts
- Faulty pressure switch
§2Safe DIY steps
- Check outdoor vent terminations for blockage
- Techniciancheck venting, inducer, hoses and pressure switch
§3When to call a pro
Call a licensed HVAC technician: if vents are clear and the code persists.
Find a local HVAC pro →§4Other Rheem codes
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).
11RheemFailed ignition. After four failed attempts the control enters one-hour lockout (10).
12RheemLow flame sense: flame sense current is weak or marginal. Furnace keeps running.
13RheemFlame lost after established.
14RheemFlame present with gas valve off. Extremely critical; furnace will not operate.
30RheemOpen fuse, usually from a 24 VAC short to common or ground.