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Goodmanfurnace

GMS80

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.

Diagnose this modelInstall notesBoard cross-refField wiring

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%.

Flashes until power is pulled. Write the count first.

Universal swap

Read the silk

Classic 80% Goodman LED. This is the plate where 50A55-843 / ICM2811 actually show up — if the silk matches.

Silk: PCBBF110 · PCBBF112 · PCBBF123 · B18099-26 · B18099-13 · 50A55

White-Rodgers

  • 50A55-843

    If the silk is already a 50A50 / 50A55 carbide module — the usual 80% PSC universal.

  • 50M56U-843

    Harness kit when you are crossing a listed single-stage HSI and may need the HotRod igniter.

  • 50M56X-843

    If the blower is PSC or ECMx (not a 9-speed tap) and the cross is on the 50M56X list.

ICM

Honeywell

  • S9200U1000

    S9200U1000 lists B18099-06/08/10/13, 102077-xx, ICM280, and 50A55-843. Classic 80% PSC job — not AR9S80 9-speed.

  • AR9S80 9-speed 0140F20001-B card — different motor.
  • A 96% condensing board. ComfortBridge.

After you pull the dead card

  1. 1Kill power. Photograph the silk-screen part number on the dead board before you pull it.
  2. 2Match staging (1 vs 2 vs modulating), igniter (carbide / nitride / spark), and motor (PSC / ECMx / 9-speed tap / serial VS).
  3. 3Set heat-off delay and any 80+/90+ jumper to the door card. Prove one full try and flame µA before you leave.
  4. 4This is metal vent. After the swap, prove draft on the chimney / B-vent. Do not prime a trap that is not here.

Field wiring

Written landings for Goodman GMS80. Not a factory schematic.

Furnace · single-stage 24V
R / C / W / Y / GGas furnace

Conventional single-stage furnace IFC. One W. Cool Y passes through to the outdoor. No ComfortBridge, no ABCD, no W2.

Written circuit description only — FieldBench does not redraw maker schematics. Example: R to W closes on a heat call; verify 24V at W1 before you change the IFC.

Open manufacturer PDF

Heat sequence

  1. 1Power. L1 / N → IFC → transformer → R120V in, 24V out
  2. 2Call. Stat W → IFC W~24 VAC
  3. 3Draft. IFC → inducer → PS close120V motor, 24V prove
  4. 4Ignite. IFC → HSI120 VAC
  5. 5Gas. IFC → valve~24 VAC
  6. 6Flame. Rod → IFCµA DC
  7. 7Blow. IFC → heat speedAfter flame prove

This indoor

Older 80% LED. One W. Metal vent.

24V single-stage heat

Door card is one-stage. Twin terminal empty unless the job is actually twinned.

Wall thermostat

Single-stage heat/cool. W2 from a leftover two-stage stat does nothing useful.

  • R24V hot from the IFC24V
  • CCommon24V
  • WHeat24V
  • YCool — also starts the outdoor24V
  • GFan24V

Furnace IFC

Transformer lives here. Y out to the outdoor contactor. TWIN empty on a standalone.

  • RHot to the stat24V
  • CCommon — must reach the outdoor24V
  • WHeat call24V
  • YCool in / cool out24V
  • GBlower24V
  • TWINEmpty unless twinned24V

Landing

  • 24VIFC Rstat R

    ~24 VAC hot

  • 24VIFC Cstat Coutdoor C

    Common

  • 24VStat WIFC W

    Heat. Stays in this cabinet.

  • 24VStat YIFC Youtdoor Y

    Cool / contactor

  • 24VStat GIFC G

    Fan. Does not go outdoors.

IFC harness — single-stage heat

After W arrives. This is the gas train, not the thermostat strip.

Transformer + fuse

120V primary. 24V secondary. Dark stat = fuse / door / transformer first.

  • L1 / N120V to the IFCLine
  • XFMR24V to R24V
  • FUSEOn the IFC24V

24V safety chain

Door, limit, rollout in series. Open anywhere kills heat.

  • DOORInterlock24V
  • LIMITMain limit — rise / no airflow24V
  • ROLLOUTManual reset. Do not jumper and leave24V

Inducer + one pressure switch

W → inducer 120V → PS closes → IFC continues. One hose, one switch.

  • IND120V from the IFC to the inducerLine
  • PS24V prove back to the IFC24V
  • HOSESingle hose. Do not add a second because two-stage boards have two.24V

HSI + single valve

Igniter is 120V from the IFC. Valve is 24V. Flame rod is µA DC back to the IFC.

  • HSI120V hot-surface igniter — not 24VLine
  • VALVE24V to the single solenoid24V
  • FLAMEµA DC on the rod. Not a 24V circuit24V

PSC blower + run cap

Heat / cool / park taps on the motor. The cap is on this blower — not the outdoor dual can.

  • HEATHeat speed tap24V
  • COOLCool speed tap24V
  • PARKUnused leads parked24V
  • CAPRun capacitor on the blowerCap

Landing

  • LineL1IFCinducer

    120 VAC after W

  • 24VIFCPSIFC

    ~24 VAC prove. Open PS = no ignition.

  • LineIFCHSI

    120 VAC during trial

  • 24VIFCgas valve

    ~24 VAC after flame prove starts

  • 24VFlame rodIFC

    µA DC. Not 24V.

  • LineIFCblower

    120V tap + cap

Prove it

  • 24 VAC from R to C at the IFC. Fuse / transformer first if the stat is dark.
  • W at the IFC under a heat call. Then inducer / igniter / valve per THIS door card.

Do not

  • Do not land a ComfortBridge 1/2 or Infinity ABCD pair on this IFC.
  • Do not hunt W2 / E8 / high-fire on a one-stage door.
  • TWIN must be empty on a standalone.

9-speed tap, PSC, and CT motors share this thermostat landing. The motor is on the IFC harness diagram.

Sequence

  1. 1

    W

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

Faults on this IFC

Step 1, then 2, then 3. Expected reading and the fail branch sit under each check.

3 flash

PS open

lockout

Metal-vent draft not proven.

  1. 1 Prove inducer and the live code

    Do not pull power — that clears the Goodman GMS80 active code. Write 3 flash. Is the inducer spinning on this call? Silent inducer is not a pressure switch. Cap, liner, common-vent tables, inducer wheel.

    Expect: 120 VAC at the inducer on a heat call. Wheel turning.

    If fail: 120 VAC missing → IFC / door switch / incoming power. Voltage + dead motor → inducer.

    If pass: Inducer running + this code → trap, hose, switch, vent (step 2).

  2. 2 Trap, collector, and the hose

    A drowned 96% trap will not make collector pressure. Pull the trap, flush it, confirm the collector box and inducer outlet are not full. Hose cracked, off the port, or full of water fakes an open switch. PS hose on the inducer housing — flue condensate on a long metal run, not a 96% collector.

    Expect: Trap flowing, hose dry and downhill, ports not swapped on a two-switch board.

  3. 3 Switch ohms, then vent load

    Ohm the pressure switch: NO, must close when that inducer speed is making the collector setpoint. If the switch is good, walk the PVC — bird screen, ice, long 2" run, wind, shared chase. Do not cut a PVC trap that does not exist.

    Expect: Switch closes on known draft. Vent unrestricted.

    If fail: Replace the open switch only after the vent and trap are proven.

    If pass: Switch closes on draft and the code stays → IFC input.

4 flash

Limit

warn

Airflow. 80% coils still dirty.

  1. 1 Airflow before you touch the limit

    On Goodman GMS80 a limit is airflow or overfire until proven otherwise. Do not replace the limit first. Filter, blower wheel, A-coil, and the heat-speed setting for THIS motor (tap, model plug, or communicating CFM — not a sister SKU chart). Filter, heat tap, A-coil on top.

    Expect: Rise in the rating-plate window. Static vs this cabinet’s blower chart.

  2. 2 Measure static and temperature rise

    Total external static vs the Goodman GMS80 blower chart for this cabinet size. Supply minus return rise after 8–10 minutes. A new 5" media cabinet or closed supplies will trip this all winter.

    Expect: Rise typically 35–65 °F — rating plate wins.

    If fail: Fix the restriction or the heat-speed setting. The limit is doing its job.

    If pass: Airflow in range → step 3 (overfire / limit itself).

  3. 3 Overfire, then the limit circuit

    Clock the meter / manifold on the stage that is tripping vs the rating plate. Then ohm the limit after it cools — a limit that never recloses is failed. Rollout in the same circuit is a different call (see rollout on this door card).

    Expect: Manifold on plate. Limit closed when cool.

6 flash

Rollout

hazard

Flame containment.

  1. 1 Treat this as flame outside the exchanger

    Do not reset the Goodman GMS80 rollout and walk away. Write the code, kill the call, and look for flame at the burners, crossover, and vestibule before you do anything else.

    Expect: No flame outside the exchanger. Burners seated. Crossover lit.

    If pass: Still inspect secondary / flue / condensate before you reset.

  2. 2 Secondary, condensate, and flue

    Blocked secondary, drowned collector, or a plugged flue pushes flame out the front. Pull the inducer/collector look, confirm the trap is flowing, and check PVC/vent. Exchanger, burners, flue. Reset only after cause.

    Expect: Dry collector, open flue, trap clear.

  3. 3 Reset only after the cause is fixed

    Manual-reset rollout. Recurring rollout on Goodman GMS80 is a CO / fire call — cracked primary, misaligned burners, or a failed secondary. Confirm CO in the space before you leave.

    Expect: One clean cycle after the cause is fixed. No second reset as a repair.

7 / 8 flash

Flame / igniter

warn

Rod or HSI.

  1. 1 Ohms at the igniter, then at the IFC

    On Goodman GMS80 measure cold ohms at the igniter plug, then at the IFC connector. An open at the plug is the element or local harness. Open only at the IFC is the harness rub-through on the collector. µA, nitride or Norton per this cabinet, gas.

    Expect: Nitride cold ohms per THIS door sticker — do not use an 80% Norton chart.

  2. 2 120 VAC during warm-up

    Call for heat and measure 120 VAC at the igniter during the warm-up window. 0 V + good ohms = IFC igniter relay. Voltage + no glow = cracked nitride.

    Expect: 120 VAC only during warm-up. Visible glow before the valve opens.

  3. 3 Do not keep cycling a cracked element

    A cracked nitride can ohm ‘good’ cold and open hot. If ohms and voltage are good and there is no glow, replace the igniter. Confirm polarity/ground (this plate’s polarity code) before you condemn a new igniter.

    Expect: One clean light after a known-good igniter and a proven ground.

Workflows

3-flash on GMS80

Do not dump the condensate trap.

  1. 1 Prove the call and the live code

    This furnace has no secondary drain. Look at the metal vent and the inducer.

    Expect: Write whatever Single-stage LED IFC (80%) is showing. Flashes until power is pulled. Write the count first.

    If fail: No call at the IFC → stat / harness. Do not change gas parts.

  2. 2 Isolate the first failed step in the sequence

    Common-vented water heater: run the tables before you change the switch.

    Expect: The first dead output or open prove.

  3. 3 Confirm with a number, then the next part

    Then the PS hose to the inducer housing.

    Expect: Vent: Cat I. Spillage is a fail.

    If fail: Stay on this plate. The out-of-range reading is the part.

    If pass: Reading in range → the next step in this workflow is the repair.

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

Install this plate

Install GMS80 / GMES80 as Category I 80%. 3-flash is chimney / draft — there is no PVC trap to dump.

Cat I metal vent · single-stage · LED 1–9 · GMS80 PSC or GMES80 multi-speed ECM

Vent

  • B-vent, masonry chimney with a listed liner, or approved common vent. No PVC, no secondary collector.
  • 3-flash = draft switch open: cap, liner, common-vent, wind, inducer. Dumping a trap that is not there will not clear it.
  • Combustion air per NFPA 54 for indoor Cat I. This is not a 2-pipe 96%.

Motor

  • GMS80: multi-speed PSC taps. GMES80: multi-speed ECM — same flashes, different motor.
  • GDS80 / GDH80 are downflow 80% twins.

First fire

  1. 1Verify vent type on the plate (Cat I) before you glue any PVC.
  2. 2W: draft switch must close. Spillage / CO at the draft hood area is a stop-work.
  3. 3Rise vs the GMS80 / GMES80 tap chart.

Do not on Goodman GMS80

  • Do not apply GMSS96 trap / collector steps.
  • Do not common-vent with a 96% Cat IV appliance.

Maker literature

FieldBench does not host manufacturer files. Each link opens the maker’s own literature page in a new tab.

  • GMS80 product pageProduct pageGMS80 PSC / GMES80 ECM 80% metal-vent family.Open manufacturer PDF
  • GMS80 specification sheetSpec sheetSearch this plate in the Goodman literature library.Open manufacturer PDF
  • Goodman literature libraryLiterature searchSearch Goodman GMS80 on the maker’s literature page.Open manufacturer PDF

Warranty and bulletins

Affected models, serial range, symptom, remedy, date. Maker files open on the manufacturer site.

All bulletins

  • Dated GM* certificate

    warranty sheet

    Older Goodman GM* furnace limited warranty

    GM* generation furnace warranty terms · Dated certificate for that generation

    Open factsOpen manufacturer PDF

  • Dealer portals

    dealer

    Where remaining service letters live

    Current-year service letters not on a public literature page · Maker dealer portal

    Open factsOpen manufacturer PDF