🔥Furnace

MECH-GAS-VALVE

Goodman · GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace

Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace MECH-GAS-VALVE Error Fix: Gas Valve Failure

The gas valve does not open when commanded by the control board — the igniter glows but no gas flows; verify 24VAC is present at the gas valve terminals during the ignition sequence; if voltage is present but valve doesn't open, the valve has failed; gas valve replacement requires qualified technician and gas leak testing after installation

Medium severity2 fixes available✨ Free fix available

Quick Answer

Error MECH-GAS-VALVE on the Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace means: Gas Valve Failure. The top-ranked community fix is “Replace Gas Valve and Perform Leak Test” (hard difficulty, ~90 min, DIY cost: $0). 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.

When to Call a Professional

While many furnace repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $400-$600.

Other Goodman Models with Error MECH-GAS-VALVE

GMVC960804CN 96% AFUE 80,000 BTU Two-Stage Gas Furnace

furnace · 2 fixes

GMVM970803BN 80,000 BTU 97% AFUE Modulating Gas Furnace with Variable-Speed ECM Blower

furnace · 2 fixes

Other Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace Error Codes

10-FLASH

Incorrect Blower Speed / DIP Switch Configuration

2 fixes

1-FLASH

System Lockout — Retry Limit Exceeded

2 fixes

2-FLASH

Pressure Switch Stuck Closed

2 fixes

3-FLASH

Pressure Switch Did Not Close

2 fixes

4-FLASH

High Limit Switch Open

2 fixes

5-FLASH

Flame Sensed Without Gas Valve Call

2 fixes

6-FLASH

Flame Lost During Operation

2 fixes

7-FLASH

Ignition Lockout — Failed to Ignite

2 fixes

People Also Ask About Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace Error MECH-GAS-VALVE

What does error code MECH-GAS-VALVE mean on a Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace?

Error code MECH-GAS-VALVE on the Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace means: Gas Valve Failure. The gas valve does not open when commanded by the control board — the igniter glows but no gas flows; verify 24VAC is present at the gas valve terminals during the ignition sequence; if voltage is present but valve doesn't open, the valve has failed; gas valve replacement requires qualified technician and gas leak testing after installation

How do I fix error code MECH-GAS-VALVE on my Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace?

The most successful fix is "Replace Gas Valve and Perform Leak Test" (hard difficulty, ~90 minutes). This fix costs nothing. HomeMD has 2 community-ranked fixes for this error.

Is error code MECH-GAS-VALVE on a Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace serious?

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Can I fix Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace error MECH-GAS-VALVE myself?

Yes — the top-ranked community fix ("Replace Gas Valve and Perform Leak Test") is rated hard difficulty and takes about 90 minutes. Tools needed: Wrench set, T20 Torx screwdriver, Gas leak detector solution, Multimeter.

How much does it cost to repair Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace error MECH-GAS-VALVE?

DIY cost: $0. Professional repair typically costs $400-$600. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace have?

The Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace has 8 other known error codes, including: 10-FLASH (Incorrect Blower Speed / DIP Switch Configuration), 1-FLASH (System Lockout — Retry Limit Exceeded), 2-FLASH (Pressure Switch Stuck Closed), 3-FLASH (Pressure Switch Did Not Close), 4-FLASH (High Limit Switch Open), and 3 more.

Which other Goodman models have the MECH-GAS-VALVE error?

Error code MECH-GAS-VALVE also appears on 2 other Goodman models: GMVC960804CN 96% AFUE 80,000 BTU Two-Stage Gas Furnace, GMVM970803BN 80,000 BTU 97% AFUE Modulating Gas Furnace with Variable-Speed ECM Blower. The fix may vary by model, so check each model's specific page for tailored repair steps.

What other error codes does the Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace have?

The Goodman GMSS920804CN 80,000 BTU 92% AFUE Single-Stage Gas Furnace has 8 other known error codes:

10-FLASH — Incorrect Blower Speed / DIP Switch Configuration (2 fixes)
1-FLASH — System Lockout — Retry Limit Exceeded (2 fixes)
2-FLASH — Pressure Switch Stuck Closed (2 fixes)
3-FLASH — Pressure Switch Did Not Close (2 fixes)
4-FLASH — High Limit Switch Open (2 fixes)
5-FLASH — Flame Sensed Without Gas Valve Call (2 fixes)
6-FLASH — Flame Lost During Operation (2 fixes)
7-FLASH — Ignition Lockout — Failed to Ignite (2 fixes)

Which other Goodman models have the MECH-GAS-VALVE error?

Error code MECH-GAS-VALVE also appears on 2 other Goodman models:

GMVC960804CN 96% AFUE 80,000 BTU Two-Stage Gas Furnace (furnace) · 2 fixes
GMVM970803BN 80,000 BTU 97% AFUE Modulating Gas Furnace with Variable-Speed ECM Blower (furnace) · 2 fixes

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