Rheem R96VA0702317MSA Error Code 57: High Pressure Switch Open, Inducer on High Speed

What Does Code 57 Mean?

The Rheem R96V is a two-stage condensing furnace with two draft-proving switches. During high-fire operation the induced-draft motor runs at high speed and the HIGH pressure switch must close to prove the stronger draft that high fire requires. Code 57 means that during high heat, with the inducer commanded to high speed, the high pressure switch did not close. This fault can appear any time in the heat call after the pre-purge and blower-on delays are complete.

What makes code 57 distinctive on this model is the furnace's response. Because it is two-stage, if the high pressure switch will not close but the LOW pressure switch is still satisfied, the R96V drops down to low-fire heat and keeps running to try to satisfy the thermostat. So high-stage heat is disabled, but the furnace may still deliver gentler low-fire heat rather than shutting off completely. That graceful step-down is only possible because of the separate low switch.

The most common cause is a blocked or improperly terminated vent, since a partial restriction may still pass low-fire draft but not the higher draft high fire needs. Vent runs that exceed the model's maximum length or elbow count behave the same way, and at high elevation a missing or incorrect high-altitude kit can reduce the high-fire draft margin. A weak inducer or a marginal high switch can also cause it.

Code 57 is the high-side counterpart to code 45 (the LOW switch failing to close at high speed) and the opposite of code 55 (the high switch stuck closed at rest). A homeowner may visually check the outdoor vent terminations for ice, snow, debris, or nests, but the hoses, inducer, switch, and any high-altitude kit work are technician-only on this sealed furnace.

What You'll Notice

• The furnace runs but only on gentle low fire and never ramps up to full high-fire heat, with the display flashing 57.
• Heating feels weak on cold days because high-stage output is locked out.
• The code may come and go during a heat call rather than appearing only at startup.
• The outdoor exhaust or intake termination shows partial blockage from ice, snow, debris, or a nest.
• Cooling and fan-only modes continue to run normally.

Common Causes

How This Is Diagnosed

The technician traces the high-fire draft path in order. They confirm the inducer runs and reaches high speed on a high-fire call, then check the outdoor terminations and the full vent run for restriction, excess length, or too many elbows. They inspect the pressure-switch hoses for splits, blockage, or condensate, then compare the high switch's continuity against the actual draft measured at high inducer speed. If strong draft is present but the high switch stays open, the switch is condemned; if the high-speed draft is weak, the problem is upstream in the venting or inducer. At elevation they verify the correct high-altitude kit. Because the furnace may still run on low fire, the tech also confirms the low switch is closing normally, and is careful to distinguish the HIGH switch at high speed (code 57) from the low switch faults (codes 45 and 46) and the high switch stuck closed (code 55).

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 furnace only runs on low heat and will not step up to full high fire.
• The outdoor vent terminations are clear but the code returns during high-fire operation.
• The home is at high elevation and 57 appears, suggesting a missing or incorrect high-altitude kit.
• Heating output is noticeably weak on cold days while the display shows 57.

✓ Verified against manufacturer service manual — March 2026