HVACopediaKeepRite · Air conditioner · Other
Split A/C: pressure switch and thermal cutout protection and lockout
What happens, in order
- High or low pressure switch opens control drops the compressor contactor and the outdoor fan keeps running for 15 minutes; code 31 (high) or 32 (low) shows
- Compressor thermal cutout (compressor voltage seen at start then gone for 10 s during a cooling demand): fan keeps running, control waits 15 minutes and tries to restart, code 72; clears after a successful restart or low-voltage power cycle
- Three trips on consecutive cycles of the thermal cutout, low pressure switch or high pressure switch lock the unit out for 4 hours (codes 82, 83, 84), or until 24 V power is cycled
- Contactor welded shut is flagged when compressor voltage is present with no demand (code 73); no 230 V at the compressor when starting is flagged as code 74
- Control brown-out (24 V under 15.5 V for 4 s) stops compressor and fan until control voltage is at least 17.5 V (code 46)
Timings and thresholds
| Item | Value |
|---|---|
| Fan run after trip | 15 min |
| Thermal cutout restart wait | 15 min |
| Consecutive trips to lockout | 3 |
| Lockout time | 4 hours |
| Brown-out cutout | under 15.5 V for 4 s |
| Brown-out recover | 17.5 V |
Codes you may see during this
Applies to: KeepRite / ICP C4A3, H4A3, T4A3, CXA6 R-410A split air conditioners
Models
More KeepRite air conditioner sequences
Take it to the job
Sequences of operation, error codes and tips work offline in the HVACopedia app.
Source: KeepRite/ICP C4A3-H4A3-T4A3-CXA6 air conditioner installation instructions 421 01 5103 05, Sequence of Operation and Control Functions. Written in our own words; timings can differ by model and software version, so check the manual for your exact unit.
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.