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
RA17 stuck on low
Y2 never arrives.
Prove Y2 at the outdoor.
410A SC on the TXV indoor.
If the plate says RA17AZ, use that chart.
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.