Rheem R802VA07542117MSA Error Code T045_F: Inducer Lo Pressure Switch Won't Close

What Does Code T045_F Mean?

Fault code T045_F on the Rheem R802VA indicates that the low-stage inducer pressure switch failed to close after 60 seconds of continuous inducer motor operation. The furnace enters a 5-minute soft lockout before automatically retrying.

Before the furnace can light the burners, the inducer (draft) motor must create a negative pressure in the combustion chamber to ensure exhaust gases will vent safely. The pressure switch verifies this draft by closing when sufficient vacuum is detected. If the switch does not close within 60 seconds, the control board will not proceed with ignition.

The most common cause is a blocked or partially obstructed exhaust vent pipe. Ice buildup during winter, bird or animal nests, and accumulated debris can all restrict the vent. A failing inducer motor that cannot generate enough suction, a disconnected or cracked pressure switch hose, or a defective pressure switch are other possible causes.

Common Causes

How to Fix It: Check the Exhaust Vent for Blockages

What You'll Need

• Flashlight
• Work gloves

Steps

1. Turn off power at the breaker or power switch AND shut off the gas supply valve Locate the furnace circuit breaker and flip it to OFF. Turn the gas shutoff valve to the OFF position (perpendicular to the pipe). If you smell gas, leave immediately and call your gas company.
2. Inspect the exhaust vent outside your home Go outside and locate the furnace exhaust vent (typically a PVC pipe on the side wall). Check for any blockages: ice buildup, animal nests, leaves, or debris. Clear any obstructions you can safely reach.
3. Check the combustion air intake pipe If your furnace has a separate intake pipe, check it for blockages as well. A restricted intake can prevent proper draft from developing.
4. Restore power and gas, then test Turn the gas supply valve to ON and flip the circuit breaker to ON. The 5-minute lockout will expire automatically. Set your thermostat to call for heat and listen for the inducer motor to start, followed by a click (pressure switch closing), and then ignition.

When to Call a Professional

Contact a licensed HVAC technician if:

• The exhaust vent is clear but the fault keeps recurring
• The inducer motor sounds weak or makes unusual noises
• You can hear the inducer running but the furnace never lights
• The pressure switch hose appears cracked, disconnected, or has water in it
• The T045_F fault escalates to an A-level alarm code

✓ Verified against manufacturer service manual — March 2026