FieldBench

York

YC2F

AC · LX · two-stage condensing unit

York LX two-stage air conditioner (YC2F 15.2 SEER2 class). Y1/Y2. Not Affinity YXT and not the YC2E single.

Not YC2E single-stage. Not YXT Affinity two-stage. Not YXV inverter.

Walk this in Diagnose

This plate

Stages
Two-stage · Y1/Y2
Control
24V Y1/Y2
Refrigerant
Read the plate — late YC2F may be R-454B

This board

LX two-stage — Y1/Y2, not Affinity communicating

  • High stage is Y2.
  • YXT is the Affinity two-stage with a different outdoor control story.

Sequence

  1. Y1. Low stage.
  2. Y2. High stage.

Faults on this IFC

  • HPS

    High pressure switch open

    lockout

    Outdoor HPS opened — coil circuit is dead. Not an inverter pressure fault and not an L-code.

    • HPS continuity, reset if manual, wiring in series with the coil.
    • Outdoor airflow: dirty coil, bent fins, fan not running (see ODF / cap).
    • Overcharge or non-condensables — confirm indoor metering before you recover (SH vs SC).
    • Do not treat this as a 25VNA drive trip.
  • ODF

    Outdoor fan fail

    warn

    Fan not turning. Compressor may still run and then HPS.

    • Dual-cap FAN section µF vs sticker. A good HERM and a dead FAN is the usual Comfort call.
    • Fan motor ohms / ground, blade clearance, capacitor wiring (C / FAN / HERM).
    • Not an inverter fan module — there isn’t one.
  • Contactor

    Contactor / coil

    warn

    Will not pull, chatters, or is welded.

    • 24 VAC at the coil under a Y call. Low voltage = long stat wire, weak indoor transformer, or a furnace 24 (fuse) problem.
    • Coil ohms / burned turns. Pitted or welded points — replace, do not file and leave.
    • Chatter: low 24V, bad coil, weak transformer — not an inverter ramp.
  • Cap

    Dual run capacitor

    warn

    HERM and/or FAN section out of rating. Single-stage Comfort dies this way all summer.

    • Both sections vs microfarad rating, not just one.
    • Bulged can, open bleed, wrong replacement (single vs dual, voltage).
    • Hard-start add-ons do not fix a dead FAN section.
  • Charge

    Charge (SH piston / SC TXV)

    warn

    Wrong charge method is as common as wrong charge.

    • Indoor piston: charge by superheat. Indoor TXV: charge by subcooling.
    • Do not use Greenspeed weigh-in-only as the only method unless the factory TXV rating plate on THIS outdoor says so. Most 24ACC are piston/TXV conventional.
    • Line-set length and indoor coil match still matter. Weigh-in after a repair, then finish on SH or SC.

Workflows

YC2F stuck on low

Y2 never arrives.

  1. Prove Y2 at the outdoor.
  2. Charge on the plate refrigerant.
  3. This is not YXV. There is no inverter.

Test points

Contactor coil
Stable ~24 VAC on Y. Chatter = voltage, coil, or HPS. No ABCD to probe.
Dual cap
HERM and FAN both within ~6% (or OEM) of the stamped µF.
Charge
SH target on piston indoor; SC target on TXV indoor. Weigh-in is a start, not a Greenspeed-only finish.
HPS
Closed at rest. Open under high head = airflow/charge, not an inverter L-code.

Gotchas

  • YXT looks like ‘the two-stage York’ on an invoice. Affinity ≠ LX.

Related plates