Rheem R96VA0702317MSA Error Code 46: Low Pressure Switch Open, Inducer on Low Speed
What Does Code 46 Mean?
A code 46 on the Rheem R96VA0702317MSA is a critical fault indicating the low pressure switch is open when the inducer is running at low speed. This specific fault only occurs during the transition to low-stage heating — the furnace always ignites at high fire, and then after the blower-on delay period, the IFC attempts to switch to low-stage operation. If the pressure switch cannot remain closed at the lower inducer speed required for low-fire, this code appears. When it does, the gas valve is de-energized, the IFC runs post-purge and blower off-delay cycles, and the furnace then attempts to restart.
The nature of code 46 is that the low-fire draft requirements are harder to meet than high-fire requirements — the inducer runs slower for low-stage, generating less negative pressure. Conditions that are borderline for the high-fire requirement (code 45) will reliably fail at the low-fire requirement. Common causes include a partially blocked vent system that allows high-fire draft but not low-fire draft, excessive vent run length or elbow count that reduces draft at low inducer speed, high altitude installations where the thinner air reduces inducer efficiency, a failing inducer motor that struggles at low speed, or a faulty pressure switch.
A technician should inspect the full vent system, check vent run specifications against the installation manual, and evaluate whether the installation is at an elevation that requires a high-altitude kit.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- Call a technician to inspect the venting system for partial blockages and verify the vent pipe length and elbow count do not exceed the maximum specifications for this model
- For installations at high elevation, the technician should determine if a high-altitude kit is required; the technician should also test the inducer motor and pressure switch at low speed conditions
✓ Verified against manufacturer service manual — March 2026