GSZ14

No 24 VAC at the contactor.

1. 1 Is Y actually at the contactor?

   On Goodman GSZ14 a silent outdoor is often no Y. Measure 24 VAC coil-to-C at the contactor on a cool call. Y and C at the outdoor. Indoor actually calling.

   Expect: ~24 VAC at the coil when the indoor is calling.

   If fail: Indoor Y / IFC / stat — not a capacitor.

2. 2 Cap and the compressor windings

   Dual run cap: herm and fan MFD ±6%. Then windings. A bad cap with a good Y is still the first cheap part — but confirm MFD, do not guess. Defrost board output to the contactor.

   Expect: MFD on the can. Even windings. Fan and compressor both try.

3. 3 Contactor and mechanical

   Pitted contactor, no mechanical close, or a welded contactor that never drops out. Replace the failed part; do not file contacts as a repair.

   Expect: Clean pull-in. Line voltage through to both loads.

Pressures do not swap with a heat/cool changeover.

1. 1 Confirm O/B is energized the way THIS outdoor expects

   Most US splits energize O in cool. Some Rheem/Ruud energize B in heat. Read the Goodman GSZ14 diagram, not a generic heat-pump card. O vs B at the stat and at the defrost board jumper. Goodman boards are not automatically Carrier O-on-cool.

   Expect: Correct 24 V at the solenoid for the mode that is failing.

2. 2 Listen for the valve, then measure

   A healthy valve slams. 24 V at the solenoid on the shift call? Voltage + no slam → valve mechanically stuck. No voltage → stat / defrost board / IFC. RV solenoid 24 VAC during the commanded shift. Tap test / pressure swap.

   Expect: Solenoid voltage present. Pressures swap after the slam.

3. 3 Stuck valve vs a defrost board that never leaves cool

   A defrost board stuck in defrost looks like ‘no heat’ with the OD fan off. If the valve is energized and pressures never swap, recover and replace the valve — do not beat on it as a repair.

   Expect: Mode change on the gauges. OD fan on in heat except during a real defrost.

Outdoor iced in heat, or runs cool-mode steam in heat all day.

1. 1 Is it actually in defrost?

   On Goodman GSZ14 confirm the board thinks it is in defrost: OD fan off, RV shifted, indoor calling heat/aux. A failed OD fan in heat ices the coil and looks like a defrost board. Outdoor coil sensor ohms vs the defrost-board chart.

   Expect: Defrost only with a cold outdoor coil, not on every call.

2. 2 Coil sensor and termination

   Defrost sensor / coil thermistor ohms vs the chart. A sensor hanging off the coil never terminates. Time/temp terminate should end with the fan back on. Board in test pins — do not leave it in forced defrost.

   Expect: Sensor seated and in range. Defrost ends. Fan restarts.

3. 3 Board vs the valve

   If the board never initiates on a frozen coil, force a defrost and watch outputs. If it initiates and never ends, sensor or board. Do not leave it in a forced defrost.

   Expect: One forced defrost that terminates. Then a normal heat cycle.

Airflow or charge.

1. 1 Heat rejection first

   On Goodman GSZ14 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. Coil, fan, indoor airflow in heat (often the missed one).

   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. Charge by SH/SC for this piston/TXV pair — not a GSZC18 weigh-in.

   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.

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