Rheem Furnace Code 55
Safety fault
High pressure switch closed with the inducer off. The high pressure switch is proving closed before the inducer starts, which should never happen. As with code 44, the manual warns it may be welded closed or bypassed in the field.
Manual wording: “HIGH PRESSURE SWITCH CLOSED, INDUCER OFF ... The high pressure control (or switch) should not be closed when the inducer is not running. If it is, this is a sign of a serious condition.”
Documented for: (-)97V, (-)96V
Likely causes, most common first
- Faulty switch
- Pressure switch physically bypassed in the field
- Loose or faulty wiring
- Abnormally high negative pressure present on vent system without inducer running
When to call a technician
Technician only. A stuck-closed or bypassed pressure switch defeats a combustion-safety interlock and has to be replaced or restored.
A Rheem furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Installation Instructions for Upflow Condensing Modulating, Communicating Gas Furnaces - (-)97V Series (92-24161-126-04) (Rheem Manufacturing Company, R97V series modulating condensing gas furnace (and R98V); TABLE 18 normal operation codes, TABLE 19 fault codes, pages 94-104) · checked 2026-08-25
- Installation Instructions for 4 Position Condensing Two-Stage, Communicating Gas Furnaces - (-)96V Series (92-24161-124-08) (Rheem Manufacturing Company, R96V series and (-)(-)96MDV two-stage condensing gas furnaces; TABLE 19 normal operation codes, TABLE 20 fault codes, pages 111-120) · checked 2026-08-25