Rheem R96VA0702317MSA Error Code 55: High Pressure Switch Closed, Inducer Off
What Does Code 55 Mean?
A code 55 on the Rheem R96VA0702317MSA is a critical fault indicating the high pressure switch is in the closed position when the inducer motor is not running. Like code 44 for the low pressure switch, this condition signals that the switch is either stuck closed or has been bypassed, because the high pressure switch should only be closed when the inducer creates sufficient negative pressure. The IFC tests both pressure switches at the start of every heat cycle — if either is already closed before the inducer starts, gas heating is blocked. Cooling and fan-only modes remain operational.
The R96VA uses both a low pressure switch and a high pressure switch to monitor venting safety at different operating conditions. The high pressure switch is designed to close at a higher negative pressure threshold than the low pressure switch. Finding it closed without the inducer running means the switch contacts are mechanically stuck or welded together, or the switch circuit has been intentionally or accidentally bypassed. An abnormally high negative pressure already present in the vent system before the furnace starts is a less common possibility.
A technician must test the high pressure switch with a multimeter to determine if contacts are stuck closed, inspect for any bypasses in the pressure switch circuit, and verify there are no unusual vent system conditions creating pre-existing negative pressure.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- Call a technician to test the high pressure switch for stuck-closed contacts and check for any unauthorized bypassing of the pressure switch circuit — both conditions require correction before safe heating can resume
- The technician should replace the high pressure switch with the correct model-specific part if it has failed, and inspect the vent system for unusual conditions
✓ Verified against manufacturer service manual — March 2026