Rheem R96VA0702317MSA Error Code 45: Low Pressure Switch Open, Inducer on High Speed

What Does Code 45 Mean?

A code 45 on the Rheem R96VA0702317MSA is a critical fault indicating the low pressure switch failed to close even though the inducer motor was running at high speed during the pre-ignition sequence. The R96VA always ignites at high fire, so this check occurs every time the furnace tries to heat. The pressure switch must close after the inducer starts and before the IFC opens the gas valve — if it does not close, ignition is blocked. Cooling and fan-only modes continue to function normally.

The most common cause is a physical obstruction in the exhaust or intake venting that prevents the inducer from building sufficient negative pressure. Ice and snow blockages at exterior vent terminations during winter are a frequent culprit. Bird nests, debris, or leaves at the vent pipe outlets are common in warmer months. Flue vent runs that are too long or have too many elbows — exceeding the maximums specified in the installation manual — create enough resistance to prevent adequate draft. A faulty or disconnected inducer motor, disconnected or split pressure switch hoses inside the furnace, or a faulty pressure switch itself are other causes.

As a first step, check the exterior vent terminations for visible obstructions. If vents are clear, a technician needs to inspect the inducer motor, pressure switch hoses, and pressure switch operation.

Common Causes

When to Call a Professional

Contact a licensed HVAC technician if:

• If exterior vent terminations are clear and the code persists, call a technician to inspect the pressure switch hoses for splits or disconnections, test the inducer motor performance, and verify the vent run lengths do not exceed specification
• The technician should also test the pressure switch itself and replace it if it fails to close at the correct negative pressure reading for this model

✓ Verified against manufacturer service manual — March 2026