Rheem R96VA0702317MSA Error Code 55: High Pressure Switch Closed, Inducer Off

What Does Code 55 Mean?

The Rheem R96V is a 4-position condensing, two-stage furnace, so it carries two draft-proving pressure switches: a low pressure switch and a high pressure switch. Both are safety interlocks that prove the sealed combustion and venting system is actually pulling a draft. Before every heat cycle the Integrated Furnace Control (IFC) verifies that each switch is OPEN while the induced-draft motor is not running. Code 55 means the HIGH pressure switch was found closed during that at-rest test.

A switch that reports a draft when no draft can exist cannot be trusted, so the furnace refuses to start. The usual causes are a high pressure switch that has welded or stuck closed, or one that has been deliberately jumped or bypassed in the field so the furnace would keep running. Either defeats the safety interlock, which is why Rheem treats code 55 as a serious condition rather than a routine no-start.

Code 55 is the high-side twin of code 44, which reports the same at-rest failure for the LOW pressure switch. It is the opposite failure from code 57, where the high pressure switch is stuck OPEN when it should have closed at high inducer speed. Because this model tests the low and high switches separately, the exact code number tells the technician which switch is at fault, so codes 44, 55, and 57 must not be treated as interchangeable.

With code 55 present the furnace will not run in gas heat, but cooling and fan modes should still operate normally if called.

What You'll Notice

• The furnace produces no heat and the dual 7-segment display shows a flashing 55.
• The inducer never spins up and the igniter never glows, because the pre-start safety check fails.
• Cooling and blower-only fan modes still operate normally.
• There may be a visible added wire or jumper across the high pressure switch terminals from a prior service call.
• The code returns immediately on every heat call rather than after a period of running.

Common Causes

How This Is Diagnosed

The technician first confirms the inducer is truly off, then meters the high pressure switch for continuity at rest. A healthy switch reads open with no draft; if it reads closed, it is welded shut or bypassed. They inspect the high switch terminals and harness for any field-added jumper, trace the wiring back to the control, and confirm the reading follows the switch itself and not a wiring short. The isolation order is: verify the inducer is off, measure the high switch at rest, look for a bypass or jumper, then confirm with a known-good replacement. On this two-stage model the tech is careful to test the HIGH switch specifically, distinguishing it from the low switch (code 44) and from the high switch's open-at-high-speed fault (code 57).

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:

• The display shows 55 and the furnace will not begin a heat cycle at all.
• There is a jumper wire or added connection across the high pressure switch that the factory did not install.
• Code 55 returns immediately on every heat call, even after power is cycled.
• The furnace was recently serviced and began showing 55 afterward, suggesting a bypass was left in place.

✓ Verified against manufacturer service manual — March 2026