FieldBench

Goodman

GLXS4B

AC · R-32 single-stage · contactor + dual cap

Current Goodman R-32 single-stage condensing unit (GLXS4B / GLXS4M / GLXS5B / GLXS3B). Contactor + dual cap, same physics as GSX16 — different refrigerant. A2L. Charge and recovery are R-32, not a 410A GSX16 top-off.

Not GSX16 / GSX14 (R-410A). Not GLXT7C (R-32 two-stage). Not GXV9S inverter. Not GSZC / GSZ heat pump.

Maker PDFs

Walk this in Diagnose

This plate

Refrigerant
R-32 (A2L). Recover / weigh on an R-32 machine. Do not mix 410A.
Stages
Single-stage scroll · one contactor
Metering
Indoor TXV / piston per the R-32 coil match — not a leftover 410A piston
Pair
24V Y from any conventional furnace / AHU
Sister SKU
GLXS4M multi-family 1.5–3 t · GLXS5B 16.5 · GLXS3B 15 · Amana ALXS4B

This board

Contactor + fan — R-32 nameplate, no communicating outdoor PCB

  • No 7-seg on this outdoor. Indoor E2 is the furnace.
  • HPS / LPS (when equipped) open the contactor coil.
  • Rating plate says R-32. A 410A gauge set and a GSX16 charge chart are the wrong book.

Sequence

  1. Y. 24 VAC at the contactor coil → compressor and outdoor fan. Indoor blower on the cool tap / G.

Faults on this IFC

  • No Y

    Outdoor silent

    warn

    No 24 VAC at the contactor or the coil is open.

    • Y and C at the outdoor. Indoor IFC / stat actually closing Y.
    • Contactor coil ohms. Do not confuse a furnace lockout with a dead outdoor.
  • Hum / no start

    Cap / start

    lockout

    Compressor hums, outdoor fan may run.

    • Dual cap (fan and herm). Replace on values, not just a bulge.
    • Hard-start only after the cap and windings are proven.
  • HPS

    High pressure

    lockout

    Outdoor airflow, overcharge, or restriction.

    • Fan running? Coil dirty? SC vs nameplate on a TXV coil.
  • LPS / freeze

    Low pressure

    lockout

    Charge, indoor airflow, metering.

    • Do not add gas on a frozen coil. Indoor filter/coil first.

Workflows

No cool, GLXS4B

Indoor running, outdoor dead, plate says R-32.

  1. This is 24V Y. There is no ComfortBridge outdoor and no inverter to reset.
  2. 24 VAC across the contactor coil. Then dual cap, then R-32 pressures.
  3. Charge: piston = SH, TXV = SC, on the R-32 chart for THIS outdoor — not GSX16 410A targets.
  4. Leak repair: recover R-32, repair, pressure-test, weigh-in + line-set. Do not top off 410A into this cabinet.

Test points

Charge
Nameplate + line-set. SH on piston, SC on TXV.
Cap
Dual can. Fan and herm both in spec.

Gotchas

  • Techs treat every Goodman box as 410A GSX16. Read the plate. R-32 machines and cylinders only.
  • GLXT7C is the two-stage R-32 cousin — Y1/Y2, not this single contactor.
  • Amana ALXS4B is the badge twin. Same R-32 story.

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