Equipment error code
Carrier code 25
Low pressure trip — suction pressure fell below the low-pressure switch or electronic cutoff during operation or start.
- Equipment
- heat pump
- Brand
- Carrier
- Source checked
- 2026-03-01
What this code means
Low pressure trip — suction pressure fell below the low-pressure switch or electronic cutoff during operation or start.
Which models show it
Carrier/Bryant heat pumps 25HCC5, 25HPA5, and cooling-only siblings with shared outdoor diagnostics.
What is actually happening
System shuts off; you may hear short cycling. In heat mode, low charge or restricted metering shows as code 25 more often than in cool.
Is it safe to keep running?
Low pressure can starve the compressor of oil return. Limit retries to one reset after filter service.
Shut it down when
Ice on outdoor coil in summer, oil stains, or hissing sounds at the unit.
What a homeowner can safely check
- Replace a dirty indoor filter.
- Ensure supply and return grilles are open.
- Check outdoor coil for heavy debris — gentle rinse only if power is off.
- Note whether the issue started after recent service — tell the technician.
When to stop
- Visible ice on refrigerant lines in cooling mode.
- Suspected leak (hissing, oil).
- Code 25 returns after one cycle.
Likely causes ranked
1. Low refrigerant charge from leak
How a tech confirms: Leak search with nitrogen or electronic detector; weighs charge.
Typical repair: $250–$1,200 · Air Conditioner Repair cost guide
2. Restricted metering device or frozen evaporator
How a tech confirms: Superheat/subcooling; inspects filter drier and indoor coil.
Typical repair: $200–$650 · Air Conditioner Repair cost guide
3. Failed low-pressure switch
How a tech confirms: Compares switch to gauge reading; replaces if opens early.
Typical repair: $225–$475 · Air Conditioner Repair cost guide
4. Weak or dead outdoor fan in cooling
How a tech confirms: Head and suction analysis with fan operation check.
Typical repair: $175–$625 · Air Conditioner Repair cost guide
Is this the end of this unit?
Major leak repair on R-410A systems past 12–15 years often pairs with full replacement when coil replacement is required.
How to clear the code
After filter change and five-minute off time, power cycle outdoor unit once. Do not bypass low-pressure switches.
Why clearing is not fixing it: Pressure rises temporarily when the unit is off; a leak or restriction brings code 25 back quickly.
Which trade to call
Call a licensed hvac contractor who works on heat pump equipment. Gas, refrigerant, and combustion faults are not general handyman jobs.
Related codes and symptom guides
More codes from this brand
Symptom guide: Air Conditioner Not Cooling