FieldBench

Goodman

GMS80

Furnace · Single-stage · 80% AFUE · LED flash · metal vent

Goodman 80% single-stage with the 1–9 LED chart. Category I metal vent. No secondary collector, no PVC trap story. 3-flash is chimney / inducer / draft switch. GMES80 is the multi-speed ECM 80% cousin — same flashes, different blower. GDS80 / GDH80 are downflow 80%.

Not GMSS96 / GMSS92 (condensing — 3-flash is a trap). Not GR9T96 / GR9S96 (7-seg). Not GMVC80 communicating 80% if the board has a triple 7-seg — that is a different IFC.

Maker PDFs

Walk this in Diagnose

This plate

AFUE
80% · Category I metal vent
Display
Red LED 1–9 flash
Blower
GMS80: multi-speed PSC. GMES80: multi-speed ECM

This board

Single-stage LED IFC (80%)

  • Same 1–9 meanings as GMSS96. Physics do not match.
  • 3-flash = metal-vent draft, not a drowned 96% collector.
  • 6-flash rollout is still a hazard. 4-flash is still the dirty A-coil on top of an 80%.

Sequence

  1. W. Inducer → metal-vent PS → HSI → valve → flame → blower. Chimney and common vent matter.

Faults on this IFC

  • 3 flash

    PS open

    lockout

    Metal-vent draft not proven.

    • Cap, liner, common-vent tables, inducer wheel.
    • PS hose on the inducer housing — flue condensate on a long metal run, not a 96% collector.
    • Do not cut a PVC trap that does not exist.
  • 4 flash

    Limit

    warn

    Airflow. 80% coils still dirty.

    • Filter, heat tap, A-coil on top.
  • 6 flash

    Rollout

    hazard

    Flame containment.

    • Exchanger, burners, flue. Reset only after cause.
  • 7 / 8 flash

    Flame / igniter

    warn

    Rod or HSI.

    • µA, nitride or Norton per this cabinet, gas.

Workflows

3-flash on GMS80

Do not dump the condensate trap.

  1. This furnace has no secondary drain. Look at the metal vent and the inducer.
  2. Common-vented water heater: run the tables before you change the switch.
  3. Then the PS hose to the inducer housing.

Test points

Vent
Cat I. Spillage is a fail.

Gotchas

  • GMES80 is the ECM 80% — same 3-flash, different motor. GDS80 / GDH80 downflow 80% same chart.
  • A tech who just left a GMSS96 will pull a trap that is not here.

Related plates

  • goodman-gmss96 — 96% flash. Same 1–9 numbers, PVC trap instead of a chimney.
  • goodman-gmss92 — 92% flash. Still condensing — trap exists.
  • bryant-800s — Bryant 80% single-stage two-digit 31 is the metal-vent analog (different OEM numbers).