GMEC96

Ignition or flame-loss retries exceeded on this call.

1. 1 Measure µA while it is running

   Do not clean first and guess. Series-µA the rod on Goodman GMEC96 during a call. Falling µA is oxide, ground, or a dying flame. A hard drop is often the pressure switch or limit opening, not the rod. Watch one full try: inducer, HSI, valve, flame, µA.

   Expect: Typically ≥ 1.0 µA DC on this family — confirm the door card. Rising while running.

2. 2 Rod, ground, then gas

   Clean the rod with a non-scratch pad — not sandpaper. Chassis ground to burner box and IFC (painted screw and missing star washer are classic). Then manifold on the stage that is dropping and confirm LP conversion leftovers. Gas supply and manifold low then high.

   Expect: Manifold low / high: Rating plate wins. Clock input if in doubt.

3. 3 Prove it is not a switch opening

   Watch the live Goodman GMEC96 display when flame drops. A PS or limit code that appears at the drop means the rod was a victim. Inducer, hose, vent wind, or a limit on a wrong heat tap. Do not keep resetting.

   Expect: µA stable and the live code stays a flame code — then rod/valve/IFC. Otherwise chase the new code.

Low-stage pressure switch is made with the inducer off. Same meaning as GR9T96 E1.

1. 1 Unplug the switch with the inducer off

   On Goodman GMEC96 this code is the switch made when the inducer is not running. Unplug that switch only. Unplug the LPS. Code change = switch or water in the hose.

   Expect: Code changes when the harness is open.

   If fail: Wrong switch, or the IFC input is shorted.

   If pass: Switch/hose path. Go to step 2.

2. 2 Water in the hose vs a welded switch

   Blow the hose. Water holding residual draft is more common than a welded switch. Confirm the hose is not teed and not routed uphill. Ohm the switch with the hose off. IFC input shorted only after the switch ohms open.

   Expect: Hose empty. Switch opens with no draft.

3. 3 IFC input last

   If the switch ohms open, the hose is dry, and the code does not change with the harness off, the Goodman GMEC96 IFC input is shorted. Do not keep swapping switches.

   Expect: Known-good open switch + open harness = code gone. If not, IFC.

Inducer on low, low-fire switch will not close. Same meaning as GR9T96 E2.

1. 1 Prove inducer and the live code

   Do not pull power — that clears the Goodman GMEC96 active code. Write E2. Is the inducer spinning on this call? Silent inducer is not a pressure switch. Inducer 120 VAC and spinning.

   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. Trap, collector, PVC, LPS hose on the low tap — not teed to high.

   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.

   Expect: LPS / HPS: Two NO switches, two hoses, two codes (E1/E2 vs E8/E9). Never teed.

   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.

Primary limit opened. On this cabinet the usual cause is the wrong CT heat tap, not a failed limit.

1. 1 Airflow before you touch the limit

   On Goodman GMEC96 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). Which heat profile is landed? CT motors have discrete 24V taps — a cool tap left on heat will trip E3.

   Expect: Heat tap: CT heat profile vs rise on the plate. Wrong tap = E3.

2. 2 Measure static and temperature rise

   Total external static vs the Goodman GMEC96 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. Filter, wheel, coil, TES vs the GMEC96 blower chart.

   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). Manifold low/high vs plate. Limit ohms after it cools.

   Expect: Manifold low / high: Rating plate wins. Clock input if in doubt.

Rod sees flame with both solenoids de-energized.

1. 1 Shut the gas cock first

   On Goodman GMEC96 the rod sees flame with the valve de-energized. Shut the cock. If flame stays, the valve is leaking — replace it. Do not jump or energize it as a test. Shut the gas cock. Leaking valve — replace, do not jump.

   Expect: Flame dies when the cock is shut.

   If fail: Leaking valve. Replace. Do not leave the unit.

2. 2 Rod and IFC flame circuit

   If flame dies with the cock shut, the rod is shorted to ground or the IFC flame circuit is lying. Unplug the rod, inspect ceramic, and check the harness for a rub-through on the collector. Rod shorted to ground or IFC flame circuit.

   Expect: Rod isolated from ground. IFC does not report flame with the rod unplugged.

3. 3 Confirm valve solenoids are actually off

   Measure 24 VAC at both solenoids after the call drops. A welded IFC relay or a shorted W will keep a solenoid wet and look like ‘unexpected flame.’ Replace the IFC only after the valve and rod are proven.

   Expect: 0 VAC at both solenoids after the call. No flame.

IFC automotive fuse is open.

1. 1 Find the 24 V short before you replace the fuse

   On Goodman GMEC96 an open IFC fuse is a short on W, Y, G, HUM, EAC, or a data pair landed on 24 V. Unplug the thermostat / data harness first. 24 V short on W, Y, G, humidifier, EAC.

   Expect: Fuse out. 24 V transformer still good. Harness isolated.

2. 2 Replace the fuse with the harness off

   New fuse, harness still off. If it holds, the short is in the field wiring or accessory. Plug one circuit back at a time (W, then Y, then HUM/EAC). Unplug tstat harness and replace fuse.

   Expect: Fuse holds with harness off. Dies when the shorted lead lands.

3. 3 If it blows with the harness off

   Short is on the Goodman GMEC96 IFC or the gas-valve harness. Unplug the valve and try once more. Repeat blow with valve unplugged = IFC.

   Expect: Do not keep feeding fuses into a welded valve coil or a burned IFC trace.

Flame present, µA below threshold.

1. 1 Measure µA while it is running

   Do not clean first and guess. Series-µA the rod on Goodman GMEC96 during a call. Falling µA is oxide, ground, or a dying flame. A hard drop is often the pressure switch or limit opening, not the rod. Clean rod, chassis ground, manifold / LP conversion.

   Expect: Typically ≥ 1.0 µA DC on this family — confirm the door card. Rising while running.

2. 2 Rod, ground, then gas

   Clean the rod with a non-scratch pad — not sandpaper. Chassis ground to burner box and IFC (painted screw and missing star washer are classic). Then manifold on the stage that is dropping and confirm LP conversion leftovers.

   Expect: Manifold low / high: Rating plate wins. Clock input if in doubt.

3. 3 Prove it is not a switch opening

   Watch the live Goodman GMEC96 display when flame drops. A PS or limit code that appears at the drop means the rod was a victim. Inducer, hose, vent wind, or a limit on a wrong heat tap.

   Expect: µA stable and the live code stays a flame code — then rod/valve/IFC. Otherwise chase the new code.

Igniter circuit did not behave as commanded.

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

   On Goodman GMEC96 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. Igniter ohms cold, 120 VAC during warm-up, cracked nitride.

   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. Harness rub-through on the collector.

   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.

High-stage switch is made with the inducer not on high. Same meaning as GR9T96 E8.

1. 1 Prove the switch is made with inducer not on high

   On Goodman GMEC96 this code means the high-fire switch is closed when it should be open. Do not treat it as the low-fire stuck-closed code. Write the live display, then unplug the high-fire switch only.

   Expect: Code should change when the high-fire harness is open.

   If fail: IFC input shorted or you unplugged the wrong switch.

2. 2 Hose water and a welded switch

   Water in the high-fire hose holds residual draft and fakes a closed switch. Route downhill to the collector. Ohm the switch with the hose off — a welded high-fire switch stays closed. Second switch — do not confuse with E1. Welded HPS, water in the hose, W2 shorted to W1.

   Expect: Hose dry. Switch opens with no draft.

3. 3 Confirm the IFC is not commanding high

   W2 shorted to W1, a communicating stat stuck on high, or an IFC that never drops inducer speed will keep this code alive. Measure W2 at the board and watch inducer speed after you open the high-fire harness.

   Expect: Inducer on low (or off) with W2 open. High-fire switch ohms open.

Inducer on high, high-fire switch never closes. Runs on low, will not go high. Same meaning as GR9T96 E9.

1. 1 Prove the high-fire call

   Write the live Goodman GMEC96 code before you pull power. Confirm this IFC is actually commanded to high — W2 at the board, or the staging timer has expired. Inducer actually changes speed on W2?

   Expect: R to W2 ~24 VAC (conventional) or a high-stage request on a communicating stat.

   If fail: No high request → thermostat / staging / menu. Not a high-fire pressure switch.

   If pass: Go to step 2. Do not jump the high-fire switch to ‘see if it runs.’

2. 2 Prove the inducer actually went high

   Listen and amp the inducer on low vs high. No speed-up → IFC high output or inducer winding. Speed-up and this code still live → high-fire PS path (hose, switch, vent). HPS hose on the high tap only.

   Expect: LPS / HPS: Two NO switches, two hoses, two codes (E1/E2 vs E8/E9). Never teed.

   If fail: Measure 120 VAC on the high-speed inducer lead during the high call. 0 V = IFC. Voltage + dead motor = inducer.

3. 3 Isolate the HIGH hose and switch

   High-fire hose on the high tap only — a tee with the low switch is the common first-install miss on this dual-switch plate. Blow the hose, confirm it is dry and downhill to the collector. Ohm the high-fire switch: it is NO and must close only on high draft. Vent capacity / condensate only under high fire.

   Expect: LPS / HPS: Two NO switches, two hoses, two codes (E1/E2 vs E8/E9). Never teed.

   If fail: Welded open, cracked hose, or water in the line. Replace the failed part — do not leave a jumper.

   If pass: Switch and hose good → step 4 (vent / condensate / IFC).

4. 4 Vent, condensate, and the IFC input

   High fire needs more draft than a low-fire code ever saw. Check PVC size on this cabinet, shared chase, wind, ice, bird screen, and condensate backing into the collector only on high. If the switch closes on known draft and the code stays, the Goodman GMEC96 IFC input is the last call.

   Expect: Clear vent, dry collector, known-good switch, then IFC.

L1/N reversed or chassis ground missing.

1. 1 Hot and neutral at the IFC, not the disconnect

   On Goodman GMEC96 polarity/ground is measured at the board. A correctly landed disconnect with a swapped whip at the IFC still throws this. Hot and neutral at the IFC.

   Expect: L1 hot, N neutral, ~120 VAC L1 to N, ~0 VAC N to ground.

2. 2 Burner-box and IFC ground

   Green ground to cabinet and IFC. Painted screw and missing star washer fail the ground check and kill flame sense. Burner box to IFC ground screw.

   Expect: Near-zero ohms burner box to IFC ground screw.

3. 3 Then flame and HSI

   Polarity/ground faults take out HSI and flame sense together. After the wiring is right, run one heat cycle and confirm µA and igniter glow before you change those parts.

   Expect: Code cleared. One clean light. µA in range.