31 High pressure switch open

What the control is telling you

The high-pressure switch (two-stage: or discharge temperature switch) opened. The compressor stops, the outdoor fan keeps running up to 15 minutes, then a restart is tried.

Applies to: KeepRite *SA5/*SA6 AC and *SH4/*SH5/*SH6 HP single-stage communicating; *CA7/*CA9 AC and *CH6/*CH9 HP two-stage communicating

Likely causes

• Overcharge
• Outdoor fan not running
• Dirty or blocked outdoor coil (cooling)
• Low indoor airflow (heat pump in heating)

Test and repair steps

1. Confirm the outdoor fan runs and the coil is clean.
2. Check refrigerant charge.
3. On a heat pump in heating, check indoor airflow and filter.
4. Cycling 24 V skips the 15 minute wait.

Models that show this code

11 models in KeepRite *SA/*SH Single-Stage Communicating, KeepRite *CA/*CH Two-Stage Communicating

Other codes on the same units

• 16 Lost communication with wall control
• 25 Model plug missing or invalid
• 32 Low pressure switch open
• 45 Outdoor control board failure
• 46 Brown-out (low voltage)
• 47 No 230 V at the unit
• 53 Outdoor air temperature sensor fault
• 55 Outdoor coil sensor fault