MECH-VENT
Goodman · GMVC960804CN 96% AFUE 80,000 BTU Two-Stage Gas Furnace
The exhaust vent pipe is partially or fully blocked — causes 3-FLASH pressure switch fault; common blockages include ice formation at the vent termination in winter, bird or wasp nests, snow drifts covering the vent, or a disconnected vent pipe section in the attic; 90%+ efficiency furnaces vent through PVC pipe which can fill with condensate if improperly sloped
Error MECH-VENT on the Goodman GMVC960804CN 96% AFUE 80,000 BTU Two-Stage Gas Furnace means: Exhaust Vent Blockage. The top-ranked community fix is “Inspect and Repair Exhaust Vent Pipe Slope and Connections” (medium difficulty, ~60 min, DIY cost: $10-$20). 2 community-ranked fixes available below.
Published February 2026 · 2 fixes · furnace
Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.
While many furnace repairs can be done safely at home, consider hiring a qualified technician if:
Average professional repair cost for this issue: $150-$250.
Incorrect Blower Speed / DIP Switch Configuration
System Lockout — Retry Limit Exceeded
Pressure Switch Stuck Closed
Pressure Switch Did Not Close
High Limit Switch Open
Flame Sensed Without Gas Valve Call
Flame Lost During Operation
Ignition Lockout — Failed to Ignite
The Goodman GMVC960804CN 96% AFUE 80,000 BTU Two-Stage Gas Furnace has 8 other known error codes:
Error code MECH-VENT also appears on 2 other Goodman models:
Ad Space — banner
Replace ADSENSE_PUBLISHER_ID in AdUnit.tsx