HVACopediaCarrier · Heat pump · Other
Variable-speed unit: low pressure protection and lockout
What happens, in order
- Low pressure transducer reads below the set limits and code 32 is shown
- After 6 minutes, if the demand is still there and pressure has recovered to the operating level, the unit restarts and clears the code
- If pressure has not recovered at the 6 minute mark the outdoor fan is turned off; the unit restarts whenever pressure recovers later
- A third consecutive drop below the no-operation level locks the unit out for 4 hours and raises code 83
- The trip counter resets after 15 minutes of successful operation
Timings and thresholds
| Item | Value |
|---|---|
| Retry delay | 6 min |
| Lockout time | 4 hours |
| Trips to lockout | 3 in a row |
| Counter reset | 15 min of good running |
Codes you may see during this
Applies to: Carrier Infinity 25VNA8 variable-speed heat pump and 24VNA9 variable-speed air conditioner
Models
More Carrier heat pump sequences
- Single-stage communicating heat pump: time delays and operating functions · Startup
- Variable-speed unit: power-up and compressor time delays · Startup
- Non-communicating heat pump: heating cycle (HK32EA001/007 and 003/008) · Heating
- Non-communicating heat pump: cooling with 5-minute compressor delay (HK32EA003/008) · Cooling
- Non-communicating heat pump: time/temperature defrost and Quiet Shift · Defrost
- Single-stage communicating heat pump: demand defrost, Auto interval and Quiet Shift-2 · Defrost
- Variable-speed heat pump: demand defrost with Auto interval · Defrost
- Single-stage communicating heat pump: pressure switch protection and lockout · Other
Related
Take it to the job
Sequences of operation, error codes and tips work offline in the HVACopedia app.
Source: Carrier Infinity 25VNA8/24VNA9 variable-speed heat pump and A/C service manual, Time Delays, Defrost, High and Low Pressure Protection. 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.