Rheem R802VA07542117MSA Error Code *A055_F: Inducer Hi Pressure Switch Won't Open (Two-Stage Only)

What Does Code *A055_F Mean?

Because your R802VA07542117MSA is a two-stage, variable-speed furnace, Rheem fits two separate inducer pressure switches: a low-stage switch for normal low-fire draft and a high-stage switch that proves the stronger draft of high fire. Code A055_F applies specifically to two-stage operation and involves that high-stage switch. It is the alarm-level, persistent counterpart of code T055_F: where T055_F is the troubleshooting report that the high-stage switch was found closed when it should be open, A055_F means that same condition has continued and the Bluetooth Communicating IFC (Integrated Furnace Control) has raised it to an alarm. A single-stage furnace has no high-stage switch and never sees this code.

A055_F is a "won't open" fault, which is the opposite of a "won't close" fault. "Won't open" means the switch is stuck closed at a time it should be open, which typically indicates a switch with welded contacts or a failed diaphragm, or a sensing hose that is trapping pressure and holding the switch closed. This is fundamentally different from code T057_F, the high-stage "won't close" fault, where the inducer runs at high fire but cannot build enough draft to close the switch, usually because of a blocked vent.

That distinction is why A055_F is not a homeowner venting-clearing job. Clearing the outdoor vent termination helps a switch that cannot close, but it does nothing for a switch that is stuck closed. Because A055_F is the alarm-level, persistent version, the high-stage switch or its hose has consistently been in the failed state rather than glitching once, so the switch is usually replaced rather than investigated further. Correcting it is technician work on a safety device that proves the furnace vents properly at high fire.

What You'll Notice

• The furnace repeatedly refuses to step up to high fire and stays on low heat or shuts down
• The furnace cannot reach full heat output over an extended period, especially on cold days
• The alphanumeric LED blinks "A055_F" one digit at a time with a roughly three-second pause between digits
• The fault keeps returning after resets rather than clearing on its own
• The condition often follows earlier T055_F reports on the same furnace

Common Causes

How This Is Diagnosed

A technician treats A055_F as a persistent "stuck closed" condition on the high-stage switch rather than a draft problem, so the outdoor vent is not the focus. The technician measures the high-stage pressure switch contacts to confirm they are electrically closed when they should be open, which indicates welded contacts or a failed diaphragm.

Because the fault has reached alarm level, the switch is generally replaced with the correct matched part for this two-stage model rather than repeatedly reset. The technician also inspects the sensing hose and port for moisture or debris that could keep the switch closed, and verifies the correct switch is installed if the alarm returns after replacement.

When to Call a Professional

This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:

• A055_F keeps returning after resets and the furnace cannot reach high fire
• The furnace runs only on low heat over an extended period
• Both T055_F and A055_F have appeared, indicating the high-stage fault is persistent
• The high-stage pressure switch or its hose is suspected of trapping pressure or moisture
• You smell gas or exhaust odor anywhere near the furnace or vent piping

✓ Verified against manufacturer service manual — March 2026