Applicable Systems
GMVC96 Furnace
GSX14 Condenser
AVPTC Air Handler
Symptoms
Pressure switch did not close after inducer motor starts; furnace will not light; possible vent blockage or inducer failure.
Possible Causes
- Vent pipe blocked or restricted
- Pressure switch tubing cracked/loose
- Inducer motor not reaching full speed
- Pressure switch faulty
Troubleshooting Steps
- Step 1: Check vent pipe for blockage (bird nest, debris)
Vent clear - Step 2: Inspect pressure switch tubing for cracks/loose fit
Tubing intact, connections tight - Step 3: Verify inducer motor reaches full speed
Inducer runs at full speed - Step 4: Test pressure switch with manometer
Pressure switch closes at correct draft - Step 5: Replace pressure switch if faulty
Furnace sequence completes
How to Reset
Clear by cycling furnace power; clear any blockage before retry.
Common Replacement Parts
- Goodman Pressure Switch P/N: B1370735
- Pressure Switch Tubing
Frequently Asked Questions
- Q: What does the pressure switch do?
Confirms adequate draft (negative pressure) from inducer motor before allowing gas valve to open. Safety device preventing gas flow without proper venting.
Source: Goodman GMVC96 Service Manual
Category: HVAC Residential