HVACopediaBosch · Heat pump
P31 Input over-current protection
What the control is telling you
The outdoor unit's input current went too high.
Applies to: Bosch IDS Light BOVA15-24/36/60 and IDS Premium Connected BOVA36-20/60-20 R-454B heat pump outdoor units
Likely causes
- Closed service valves
- Loose compressor wiring
- Shorted compressor
- Board fault
Test and repair steps
- Warning: Switch off power and wait 3 minutes before measuring resistance or touching boards.
- Open valves; correct compressor wiring.
- Check compressor windings U/V/W and to ground.
- Compare input current with the point check value.
- Replace the board, then the compressor, if needed.
Models that show this code
5 models in Bosch IDS Light, Bosch IDS Premium Connected
Other codes on the same units
- P4 High compressor discharge temperature
- P5 Condenser coil temperature protection (cooling)
- P11 High pressure protection (transducer)
- P21 Low pressure protection
- P32 Compressor over-current protection
- AtL Ambient temperature limited
- EA Control and drive program mismatch
- PH Low discharge superheat protection
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Source: Bosch IDS Light installation BTC 762003308 D (02.2025), Fault Code Table 23 and 17.12 Error Code Troubleshooting, p.42-59; Bosch IDS Premium Connected installation BTC 762003301 D (02.2025), Fault Code Table 22 and 18.12 Error Code Troubleshooting. 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.