FieldBench
Models
Amanaac

ASXC18

Two-stage / communicating outdoor · 18 SEER class

Amana-badge two-stage communicating condensing unit. Same outdoor family as Goodman GSXC18. Codes are on the outdoor board. ComfortBridge indoor (AMVC / AVPTC) or 24V Y1/Y2.

Not ASX16 (single-stage contactor). Not AXV9S inverter. Not ASZC18 heat pump. Not ALXT7C (R-32 two-stage).

Diagnose this modelInstall notesBoard cross-refField wiring

Stages

Two-stage scroll

Refrigerant

R-410A on this generation

Pair

ComfortBridge AMVC / AVPTC or 24V Y1/Y2

Sister SKU

Goodman GSXC18 · AVXC20

This board

Outdoor communicating control (Amana badge)

  • Outdoor board, not the AMVC96 E-codes.
  • Comm faults are invalid on a 24V AR9T96 / AR9S96 hookup — land Y1/Y2.

Outdoor LED / display before the disconnect.

Universal swap

No universal

Amana ASXC18 outdoor. No furnace IFC universal. Replace the OEM outdoor control / contactor / drive by the silk.

Silk: ASXC18

White-Rodgers

—

ICM

—

Honeywell

—
  • Indoor furnace universals (50A55, 50M56U, ICM282B, ICM2811, S9200U). This is not an IFC.
  • Do not ‘adapt’ a furnace board to an outdoor inverter, defrost PCB, or contactor.

After you pull the dead card

  1. 1Photograph the outdoor silk. Indoor 50A55 / ICM282B / S9200U do not belong here.
  2. 2Contactor units: replace the contactor / cap / HPS — there is no universal outdoor board.
  3. 3Inverter / communicating outdoors: OEM drive only. There is no White-Rodgers or ICM outdoor universal.

Field wiring

Written landings for Amana ASXC18. Not a factory schematic.

ComfortBridge two-stage outdoor
1/2 data — or 24V Y1/Y2R-410A

Goodman GSXC / Amana ASXC class. Talks ComfortBridge on 1 and 2 when the indoor is GMVC / AMVC / AVPTC. On a 9-speed 24V indoor it is just Y1/Y2.

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

This indoor

AMVC / AVPTC on 1/2. AR9T96 = Y1/Y2 only.

ComfortBridge indoor

GMVC96 / AMVC96 / AVPTC / ARVT96 on the data pair.

CoolCloud / communicating control

Menus live on the indoor. Do not land R/C on 1 and 2.

  • 1DataData
  • 2DataData

Communicating indoor

One master on the bus. 1/2 polarity matters.

  • 1DataData
  • 2DataData
  • R24V for accessories24V
  • CCommon24V

ComfortBridge pair

Indoor 1 and 2 to outdoor 1 and 2. Polarity matters. This is not 24V Y.

  • 1DataData
  • 2DataData

Outdoor line

208/230 through the disconnect to the contactor line side.

  • L1LineLine
  • L2LineLine
  • GNDEquipment groundLine

Landing

  • DataIndoor 1outdoor 1 · indoor 2outdoor 2

    Data. Not 24 VAC.

  • LineL1 / L2outdoor

    208/230

24V indoor (GR9 / AR9 / GMEC)

9-speed or CT indoor. No ComfortBridge menus.

Wall thermostat

Two-stage cool. A single-Y stat never pulls high.

  • R24V hot24V
  • C24V common24V
  • Y1Low-stage cool24V
  • Y2High-stage cool24V
  • GIndoor fan24V
  • WHeat. Stays at the indoor.24V

Indoor IFC / AHU

Y1 and Y2 both have to leave this cabinet on high.

  • RTransformer hot24V
  • CCommon — run it to the outdoor24V
  • Y1Low-stage in / out24V
  • Y2High-stage in / out24V
  • GBlower24V
  • W1Heat24V

Outdoor — Y1 / Y2

Low vs high is these two screws, not an inverter L-code.

  • Y1Low-stage request24V
  • Y2High-stage request24V
  • C24V common24V

Outdoor line

208/230 through the disconnect to the contactor line side.

  • L1LineLine
  • L2LineLine
  • GNDEquipment groundLine

Landing

  • 24VStat Y1/Y2/Cindooroutdoor Y1/Y2/C

    ~24 VAC. Data wire is a miswire.

Prove it

  • Identify the indoor first. Communicating indoor = 1/2. 24V indoor = Y1/Y2.
  • Comm faults are invalid on a 24V hookup.

Do not

  • Do not land data wire on a GR9T96 / AR9T96 / GR9S96.
  • Do not apply this to GSX16 / GLXS4B or GXV9S / AXV9S.

1 and 2 are the published ComfortBridge pair.

Sequence

  1. 1

    Y1 / low

    Outdoor starts low capacity. Indoor blower on low/mid Cool tap (24V) or communicating CFM (ComfortBridge indoor).

  2. 2

    Y2 / high

    Second stage. Head and subcooling should rise into the OEM SC window.

  3. 3

    Communicating pair

    GMVC96 / AVPTC indoor requests capacity on the data pair. No conventional Y needed. A 24V GR9T96 on that same pair is a miswire.

Faults on this IFC

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

HPS

High pressure

lockout

Outdoor airflow, overcharge, or restriction opened the high-pressure switch.

  1. 1 Heat rejection first

    On Amana ASXC18 high pressure is outdoor airflow until proven otherwise. Fan running the right direction, coil clean, fins not folded, no recirc over a fence or through a garage. Outdoor fan running? Coil dirty, recirc, bent fins.

    Expect: OD fan on, coil clean, discharge air leaving the top/side freely.

  2. 2 Head, subcooling, and liquid line

    Liquid pressure and liquid-line temperature → SC. High head + high SC = overcharge or non-condensables. High head + low SC = restriction or a dying compressor. Do not add gas because suction is low. Subcooling vs indoor TXV sheet. Liquid-line drier / restriction.

    Expect: SC vs the metering device on this plate (TXV ≠ piston).

  3. 3 Restriction vs the switch

    Drier, liquid-line kink, TXV inlet screen, or a non-feed indoor coil will stack head. Ohm / jumper-test the HPS only as a momentary prove, then restore it. A switch that opens on a known-good charge and clean coil is the switch. Do not keep resetting HPS into a locked fan.

    Expect: HPS closed at a normal liquid pressure for this refrigerant and OD ambient.

LPS

Low pressure / freeze

lockout

Suction dropped out — charge, indoor airflow, or TXV.

  1. 1 Airflow and freeze before you add gas

    On Amana ASXC18 low pressure / freeze is indoor airflow or a starved coil until proven otherwise. Filter, blower, dirty A-coil, closed supplies. In heat mode, a iced outdoor coil is the same family. Indoor filter, blower, coil freeze. Do not add gas on a frozen coil.

    Expect: Indoor air moving. Coil not iced. OD coil clear in heat.

  2. 2 SH / SC after a thaw

    Thaw fully. Then SH and SC vs the metering device. Low charge ices a piston. A TXV stuck closed ices with high SH. A restriction downstream of the ports fakes a low-charge chart. TXV / restriction. Weigh-out if the history is a leak.

    Expect: SH/SC in range for this refrigerant and device after a stable 10-minute run.

  3. 3 Leak, TXV, then the LPS

    Weigh-in if the chart says undercharge. Soap / electronic leak on joints and the coil. LPS that opens on a known-good charge and a clear coil is the switch — momentary test only, then restore. Low ambient and wind can nuisance-trip LPS on a light load — still prove charge.

    Expect: Charge on the nameplate. LPS closed at a normal suction for this OD ambient.

Comm

Indoor/outdoor data

lockout

ComfortBridge data pair only. Invalid as a diagnosis on a 24V Y1/Y2 hookup.

  1. 1 Data pair, not 24 V

    On Amana ASXC18 indoor/outdoor comm is a data pair (AB, S1/S2, U, ComfortBridge, ComfortLink — whatever THIS plate uses). It is not a 24 V Y. Check polarity, continuity, and that nobody landed it on R/C. Data pair polarity and splices. This is not 24V Y.

    Expect: Pair continuous, not shorted to chassis, polarity per the diagram.

  2. 2 Power both ends, then the outdoor status

    Indoor transformer and outdoor control both alive. Read the outdoor LED / 7-seg. Water in the outdoor control is the usual dead-end after a storm. Indoor IFC family must be GMVC / AVPTC communicating. GR9T96 / GMEC96 / GMSS96 cannot be the ComfortBridge indoor.

    Expect: Both controls powered. Outdoor showing a comm or address state, not a blank board.

  3. 3 Address / bias, then the control

    Communicating plates need a matching indoor address and sometimes a terminating bias. Swap is last: known-good pair + power both ends + correct address. One master on the bus. Outdoor board power before you condemn the indoor IFC.

    Expect: Indoor sees the outdoor. No comm code after a power cycle.

Workflows

No cool, ASXC18 + AR9T96 indoor

Mixed 24V Amana 9-speed indoor + two-stage outdoor.

  1. 1 Prove the call and the live code

    This pair is 24V Y1/Y2. No ComfortBridge indoor menus.

    Expect: Write whatever Outdoor communicating control (Amana badge) is showing. Outdoor LED / display before the disconnect.

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

  2. 2 Isolate the first failed step in the sequence

    Y1 then Y2 at the outdoor. Charge by SC on the TXV coil.

    Expect: Y2 / high: Second stage. Head and subcooling should rise into the OEM SC window.

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

    Data wire to an AR9T96 is a miswire.

    Expect: Charge: Nameplate + line-set adders. SC per indoor TXV sheet. · Y1 / Y2: 24V pair: both present on high stage. Communicating pair: data, not 24 VAC.

    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

Charge

Nameplate + line-set adders. SC per indoor TXV sheet.

Y1 / Y2

24V pair: both present on high stage. Communicating pair: data, not 24 VAC.

Outdoor board

LED/display before the disconnect. Codes die when you pull power.

Gotchas

  • Goodman GSXC18 is the factory twin. Same outdoor board family.
  • ASZC18 adds the RV and defrost — different chart.

Related plates

Install this plate

Install Amana ASXC18 as Two-stage / communicating outdoor · 18 SEER class.

Two-stage / communicating outdoor · 18 SEER class

This plate — not the sister SKU

  • Not ASX16 (single-stage contactor). Not AXV9S inverter. Not ASZC18 heat pump. Not ALXT7C (R-32 two-stage).
  • Goodman GSXC18 is the factory twin. Same outdoor board family.
  • ASZC18 adds the RV and defrost — different chart.

Control on this outdoor

  • Outdoor board, not the AMVC96 E-codes.
  • Comm faults are invalid on a 24V AR9T96 / AR9S96 hookup — land Y1/Y2.

Hardware

  • Stages: Two-stage scroll
  • Refrigerant: R-410A on this generation
  • Pair: ComfortBridge AMVC / AVPTC or 24V Y1/Y2
  • Sister SKU: Goodman GSXC18 · AVXC20

First fire

  1. 1This pair is 24V Y1/Y2. No ComfortBridge indoor menus.
  2. 2Y1 then Y2 at the outdoor. Charge by SC on the TXV coil.
  3. 3Data wire to an AR9T96 is a miswire.

Do not on Amana ASXC18

  • Not ASX16 (single-stage contactor). Not AXV9S inverter. Not ASZC18 heat pump. Not ALXT7C (R-32 two-stage).
  • Goodman GSXC18 is the factory twin. Same outdoor board family.
  • ASZC18 adds the RV and defrost — different chart.

Maker literature

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

  • Amana literature libraryLiterature searchGas furnace / air-handler PDFs. Match the plate, not just the Amana badge.Open manufacturer PDF

Warranty and bulletins

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

All bulletins

  • Standard limited warranty

    warranty sheet

    Amana furnace heat-exchanger / unit-replacement terms

    Registered residential furnace warranty terms · Limited warranty certificate

    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