FieldBench
Trane codes

Trane

HPS / LPS

Lockout

Pressure protection

Still real on an inverter. High = outdoor airflow / overcharge / restriction. Low = charge, indoor airflow, metering.

Walk HPS / LPS in Diagnose

2 plates — walk the one on the cabinet

First check

1 Let it cool, then read the drive LED

On Trane XV18 overcurrent / overheat is often a dirty coil, a failed OD fan, or a locked compressor — not a dead inverter. Clear airflow, confirm the OD fan, and read the drive LED before you order a control. Outdoor fan actually running? A failed outdoor fan on this unit is a drive/fan-motor path, not a cap.

Expect: OD fan running. Coil clean. Drive LED decoded from THIS outdoor’s card.

The rest of the walkthrough is Diagnose.

On the plates

  • Outdoor fan actually running? A failed outdoor fan on this unit is a drive/fan-motor path, not a cap.
  • Coil cleanliness both sides.
  • Charge is weigh-in + line-set. Do not ‘top off’ to a piston SH number.

Plates that use HPS / LPS

Same number, other makers

HPS / LPS on Trane is not the same code on these plates.