Rheem R802VA07542117MSA Error Code A055_F: Inducer Hi Pressure Switch Won't Open
What Does Code A055_F Mean?
Fault code A055_F on the Rheem R802VA is the alarm-level (persistent) version of T055_F, occurring only on two-stage models. It indicates that the high-stage inducer pressure switch is persistently stuck in the closed position when the IFC expects it to be open. Unlike the T (troubleshooting) variant which indicates an intermittent occurrence, the A (alarm) prefix means this condition is ongoing and has triggered a lockout.
The high-stage pressure switch in a two-stage R802VA furnace is a dedicated safety device that monitors draft pressure at high-fire operation. Its contacts should be open at rest, and it should only close when the high-speed inducer creates adequate negative pressure in the venting system. When it remains closed continuously, the IFC cannot verify correct switch operation and blocks the heating cycle.
Because this is an alarm-level fault rather than a troubleshooting flag, the switch or its sensing system has been consistently in this failed state. The switch diaphragm may have failed, the contacts may be welded, or condensation may be blocking the sensing port.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| High-stage pressure switch stuck in closed position | Most common | ✗ Call a pro → |
| Defective pressure switch with welded contacts | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- Any time this code appears — the high-stage pressure switch needs professional testing and likely replacement
- A technician should check the high-stage pressure switch sensing hose and port for moisture or debris causing the switch to remain closed
- If both T055_F and A055_F have appeared, the fault is persistent and the switch should be replaced rather than investigated further
✓ Verified against manufacturer service manual — March 2026