AMVC96

This board

ComfortBridge IFC · three 7-segment digits + menu buttons

• Three digits, not the AR9T96 single 7-seg. Status words (idle, Ht1, Ht2, CF, CL1, CL2) are run states, not faults. Do not replace a board because it says Ht1.
• Faults are letter+digit: E0–E9, EA, EE, b0–b9, d0/d4. Write the exact token off THIS door card — ComfortBridge menus moved between board generations.
• Shared-data memory card is required after an IFC swap. d0 = no card / empty set. d4 = wrong-model card. The replacement board will not drive the serial ECM without the correct AMVC96 card.
• ComfortBridge Bluetooth / CoolCloud is the menu for CFM, outdoor type, and (on an AHU) electric heat. On this furnace the heat CFM still comes from IFC tables, not 9-speed taps.
• 24V fallback exists (W1/W2/Y/G). CFM still comes from the IFC tables, not tap plugs. A leftover data pair shorted to R/C will look like a dead bus.
• A communicating outdoor on the same bus changes what a ‘no Y’ complaint means — the IFC may be the thermostat.

Sequence

1. Call. Communicating stat requests heat capacity. On 24V fallback, W1/W2 behave like a two-stage furnace but blower CFM still comes from the IFC tables, not taps.
2. Prove limits. IFC proves primary/aux/rollout closed. Open limit → E3. Open 24V fuse → E5. No 115V / door switch / internal → EE.
3. Low inducer / LPS. Two-speed inducer starts low. Low-stage PS must close. Already closed with inducer off → E1. Never closes (5 min then 1-hour lockout) → E2. Same physics as AR9T96, E1/E2 on this board.
4. HSI / low-fire valve. Silicon nitride warm-up, then first-stage solenoid. Open igniter / no-ground → E7. Flame must prove at the rod. Failures stack toward E0 (3 retries, 1-hour auto reset).
5. Blower. Serial ECM ramps to the IFC heat CFM table. No tap plugs. Silent motor → b0/b1. Wrong motor HP vs the shared-data set → b2. Do not hang an AR9T96 9-speed motor on this harness.
6. High fire. Communicating capacity or W2. Inducer goes high. High-stage PS must close (E9 if open — no high fire; E8 if it was already closed — runs low only). Second-stage solenoid opens.
7. Satisfied. Valve off, inducer post-purge, blower heat-off delay. Unexpected flame after valve-off → E4.

Faults on this IFC

• idle / Ht1 / Ht2 / CF / CL1 / CL2

  Status, not a fault

  info

  Normal run states on the triple display. idle = standby. Ht1 / Ht2 = low / high heat. CF = continuous fan. CL1 / CL2 = cooling stage.

  • Do not replace the board because it says Ht1 or CF.
  • CF is continuous-fan CFM, not a capacitor.
  • Ht1 forever with a high-fire request → staging / E8–E9 path, not a ‘bad Ht1 code.’
• E0

  System / ignition lockout

  lockout

  Control failed to sense flame after 3 full ignition retries and shut off gas. Auto-resets after 1 hour (or a tstat cycle).

  • Watch one full try: inducer, HSI glow, valve click, flame, µA.
  • Gas supply and manifold (low then high).
  • Ground and flame-rod cleanliness.
  • Do not sit on hourly resets — find which step dies.
• E1

  Low-stage PS stuck closed

  lockout

  Low-stage pressure switch is made with the inducer off. Control waits for the fault to clear.

  • Unplug the LPS. If the code changes, the switch is welded or the hose is holding residual draft.
  • Hose routed downhill to the collector? Water in the hose fakes a closed switch.
  • IFC input shorted — only after the switch ohms open.
• E2

  Low-stage PS stuck open

  lockout

  Inducer is on low and the low-stage switch did not close within 5 minutes. Then 1-hour lockout and retry.

  • Inducer spinning? 120 VAC at the inducer on a heat call.
  • Collector box, inducer outlet, and condensate trap — this 96% will not make pressure with a full trap.
  • PVC intake/exhaust (bird screen, ice, long run, wind).
  • LPS hose cracked or on the wrong port (low vs high tap).
• E3

  Open primary / aux / rollout limit

  warn

  A limit opened. Both blowers typically run until it recloses. Airflow or overfire — not a charge problem. Rollout is still a manual-reset hazard.

  • IFC heat CFM setting, not a 9-speed tap.
  • Filter, blower wheel, A-coil, return size, total external static.
  • Manifold pressure on low and high vs rating plate.
  • Limit ohms after it cools. Recurring rollout → exchanger / burners / flue before you reset and leave.
• E4

  Flame sensed with no call for heat

  hazard

  Rod sees flame with both solenoids de-energized. Control runs circulator and inducer and will not fire again.

  • Shut the gas cock. If flame stays, leaking valve — replace, do not jump.
  • Rod shorted to ground or IFC flame circuit.
  • Treat as a hazard until the valve is proven closed.
• E5

  Open 24V fuse

  warn

  Low-voltage fuse on the IFC is open. All furnace operation is inhibited except the error display.

  • 24 V short on W, Y, G, humidifier, EAC, or a leftover data pair landed on R/C.
  • Unplug the tstat / data harness and replace the fuse. If it blows again the short is on the board or gas-valve harness.
• E6

  Low flame-sense µA

  warn

  Flame is present but the micro-amp signal is below the IFC threshold.

  • Clean rod with a non-scratch pad — not sandpaper.
  • Chassis ground to burner box and IFC.
  • Manifold pressure / orifice / LP conversion.
• E7

  Igniter open / no-ground

  lockout

  Igniter is open, not connected, or the IFC failed its ground check on the igniter circuit.

  • Igniter ohms cold (confirm sticker — nitride, not a 80% Norton chart).
  • 120 VAC to igniter during warm-up.
  • Cracked nitride element. Burner-box ground screw and painted-cabinet star washer.
• E8

  High-stage PS stuck closed

  lockout

  High-stage pressure switch is made with the inducer not on high. Furnace runs low only regardless of demand.

  • This is the second switch — do not confuse with E1.
  • Welded HPS or water-filled hose.
  • IFC calling high when it should be low — W2 shorted to W1 on 24V fallback.
• E9

  High-stage PS stuck open

  lockout

  Inducer on high, high-stage switch never closes. Classic ‘runs on low, will not go high.’

  • Inducer actually changes speed on a high-fire request? Listen / amp it.
  • HPS hose on the high-fire tap, not teed to the low switch.
  • Vent capacity / wind / shared chase. High fire needs more draft than E2 ever saw.
  • Condensate backing into the collector only under high fire.
• EA

  Reversed polarity / poor ground

  lockout

  L1/N reversed or chassis ground missing. HSI and flame sense both suffer. Furnace will not operate.

  • Hot and neutral at the IFC, not just the disconnect.
  • Burner box to IFC ground screw.
  • 24V transformer leads swapped on a replacement IFC.
• EE

  No 115V to control / internal / door switch

  lockout

  No line voltage reaching the IFC, door switch open, or an internal control condition. This is power, not a ComfortBridge data-pair code.

  • Furnace switch, breaker, and blower-door switch fully made.
  • 115 VAC at L1/N on the IFC.
  • Do not confuse EE on this board with a comms complaint — check the data pair separately if the stat is dark and the IFC is alive.
• b0

  ECM blower not running

  lockout

  IFC commanded the serial ECM and does not detect it running. Furnace will not operate.

  • 14-pin harness seated at motor and IFC. No tap plugs on this motor.
  • 120 VAC to the motor, wheel free, no wet winding.
  • Do not install an AR9T96 9-speed motor as a ‘cheaper ECM’ — it will not talk this serial bus.
• b1

  ECM communications lost

  lockout

  IFC cannot communicate with the variable-speed blower. Furnace will not operate.

  • Same 14-pin harness — pins bent, corrosion, half-seated.
  • Motor vs IFC: if a known-good motor still b1s, the IFC serial driver is the fault.
  • Power-cycle once to see if it is a hard loss or a glitch after a static event.
• b2

  Motor HP mismatch vs shared-data set

  lockout

  Connected motor horsepower does not match the value in the furnace shared-data set. Furnace will not operate.

  • Wrong replacement motor for this cabinet size.
  • Wrong memory card after an IFC swap (see d0/d4).
  • Do not ‘make it work’ with a different HP ECM — ComfortBridge CFM tables are card-specific.
• b3

  Motor limiting (power / speed / temp)

  warn

  ECM is folding back on power, speed, or temperature. Furnace keeps running at reduced CFM.

  • Filter, coil, and total external static vs the AMVC96 blower chart.
  • Return undersized or a 5" media cabinet the installer added.
  • High ambient around the motor (closet, no ventilation).
• b4 / b5 / b7

  Motor trip / locked rotor / failed start

  lockout

  b4 = lost rotor or overload trip (shuts down and retries). b5 = locked rotor after 10 start attempts. b7 = motor parameters missing or failed to start after 40 attempts.

  • Wheel rub, debris in the housing, seized bearings.
  • Static so high the motor cannot start the wheel.
  • Harness intermittents look like b7. Prove the 14-pin before a motor or IFC.
  • Adjacent b-codes on some door cards are the same family — same harness/static/motor path.
• b9

  Low indoor airflow

  warn

  Indoor airflow fell below the calculated minimum. Furnace stages down (high to low) and will halt if CFM reaches 0.

  • Filter, coil, closed registers, undersized return.
  • IFC heat/cool CFM setting vs the coil and the outdoor.
  • TES. A communicating motor will ramp into a brick and then b9 / E3.
• d0 / d4

  Shared data / memory card

  lockout

  d0 = IFC has no shared-data set (replacement board, missing card) and cannot drive the serial ECM or calculate CFM. d4 = card rejected (wrong model card).

  • After an IFC swap the AMVC96 memory card must be installed and seated.
  • A GMVC96 card usually twins; an AMVM97, AVPTC, or AR9T96 card is d4.
  • Do not run the furnace on empty shared data and guess CFM.

Workflows

Test points

Data pair

OEM communicating voltage / polarity — never 24 VAC between the data pins.

Motor harness

14-pin serial ECM, fully seated. No tap plugs. Do not hang an AR9T96 9-speed here.

Flame rod

µA per this IFC sticker, not the AR9T96 card. Rising while running is the goal.

LPS / HPS

Both NO. Two hoses, two taps, never teed. Closed only when that inducer speed is making the collector setpoint.

Manifold low / high

Natural ~1.6–1.9 / 3.2–3.5 in. w.c. class — rating plate wins. Clock input if in doubt.

HSI

Nitride, 120 VAC during warm-up. Cold ohms per sticker.

Memory card

Seated AMVC96 (or GMVC96 twin) card after any IFC swap. d0 empty, d4 wrong card.

24V fuse / door

Fuse intact (E5). Door switch made, 115 VAC at L1 (EE if not).

Gotchas

• Techs treat AMVC96 like AR9T96 and start counting a single 7-seg or looking for heat taps. There are none. Triple display + 14-pin serial motor.
• EE on this board is line voltage / door / internal — not a ComfortBridge comm code. A dark stat with a live IFC is a data-pair problem, not EE.
• E2 vs E9: fixing the trap clears low fire and the callback is ‘still no high fire’ because the HPS hose was never on the high tap. Dual PS still exist.
• AMVM97 looks identical in the basement and is modulating. W1/W2 staging tests and E8/E9-as-a-tee will lie. Confirm the valve and the data plate.
• GMVC96 is the Goodman-badge twin. Same IFC, same card family, same chart. GM9S96 / GR9T96 are not.
• Door cards differ by board generation. A 2014 AMVC96 card is wrong on a later triple-display replacement IFC — read the sticker in THIS blower.
• 24V fallback does not turn this into a tap furnace. CFM still comes from the IFC tables. Wrong CoolCloud outdoor type / CFM is an E3/b9 generator.

Related plates

• amana-arvt96 — Newer ComfortBridge two-stage VS R-32 plate. Same E/b/d language — ARVT96 memory card, 0.5" heat-ESP hard limit. Do not drop this AMVC96 card into that cabinet.
• amana-amvm97 — Modulating cousin — 0–100% valve and variable inducer. Do not apply AMVC96 two-stage staging tests.
• goodman-gmvc96 — Goodman-badge twin. Same ComfortBridge IFC and the same E/b/d chart.
• amana-ar9t96 — 9-speed tap, conventional 24V, single 7-seg. Do not use that chart on this communicating VS IFC.
• amana-avptc — Matching ComfortBridge communicating air handler — electric heat, no gas, no inducer.