HVACopediaKeepRite · Air conditioner
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 C4A3/CXA6 AC with outdoor control board; *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
- Confirm the outdoor fan runs and the coil is clean.
- Check refrigerant charge.
- On a heat pump in heating, check indoor airflow and filter.
- Cycling 24 V skips the 15 minute wait.
Settings for these units
Outdoor unit clearances · KeepRite C4A3/CXA6 AC
| Location | Minimum |
|---|---|
| Service end | 24 in. (610 mm) |
| Above unit | 48 in. (1219 mm) |
| One side | 6 in. (152 mm) |
| Other sides | 12 in. (305 mm) |
| Between units | 24 in. (610 mm); 18 in. (457 mm) with no overhang within 12 ft |
| Roof mount height above roof | 6 in. (152 mm) |
| Shrubs/fences from coil | 18 in. (457 mm) |
Keep roof run-off and snow from falling on the unit.
Unit must be level within 2 degrees.
Models that show this code
12 models in KeepRite C4A3/CXA6 AC, KeepRite *SA/*SH Single-Stage Communicating, KeepRite *CA/*CH Two-Stage Communicating
Other codes on the same units
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Source: KeepRite/ICP C4A3/H4A3/T4A3/CXA6 Installation Instructions 421 01 5103 05, Table 1 Status Codes, p.17; KeepRite_ICP_KeepRite_Tempstar_Heil_split_A_C_HP_R_410A_R_22_service_421_08_5400_04.txt - section Table 13 Status Codes (single-stage); KeepRite_ICP_KeepRite_Tempstar_Heil_split_A_C_HP_R_410A_R_22_service_421_08_5400_04.txt - section Table 17 Troubleshooting (two-stage). Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.