264 on a NIBE heat pump: Communication error with inverter (generated by heat pump): Communication between inverter circuit board and control card interrupted [other NIBE documents: Communication between inverter board and control board/PCB interrupted / Communication between inverter circuit board and control board broken]
Short answer
On a NIBE heat pump, 264 means: Communication error with inverter (generated by heat pump): Communication between inverter circuit board and control card interrupted [other NIBE documents: Communication between inverter board and control board/PCB interrupted / Communication between inverter circuit board and control board broken]. The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Communication error with inverter (generated by heat pump): Communication between inverter circuit board and control card interrupted [other NIBE documents: Communication between inverter board and control board/PCB interrupted / Communication between inverter circuit board and control board broken].
Part involved: PCB / accessory board communication.
When it shows: Communication between inverter circuit board and control card interrupted; Communication between inverter board and control board/PCB interrupted; Communication between inverter circuit board and control board broken; Alarm 203 from the air/water heat pump for 20 seconds; Alarm 203 from heat pump for 20 seconds; Communication between inverter circuit board and baseboard interrupted; Communication between inverter board and control board broken.
Likely causes:
- F2120: Inverter disconnected; loose cables between inverter and base board; defective inverter board or base board in F2120 | F2120: Poor connection between PCB and inverter; inverter unpowered or broken | S2125: Poor connection between PCB and inverter; inverter unpowered or broken | S2060: Poor connection between PCB and inverter; inverter unpowered or broken; defective baseboard AA2 | F2050: Open circuit in connection between boards; defective inverter board; defective PWB1 | F2040: Open circuit in connection between boards; defective inverter board; defective control board.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: no/unknown - Compressor blocked.
Manual reset: Reset from the controller alarm menu ('reset alarm' / 'Reset alarm and try again'); alarm recurs if the cause remains.
What you can check
- Read the alarm text and the 'info/action' help on the controller display (VVM/SMO or S-series smartguide). NIBE's manuals let the homeowner select 'reset alarm' ('Reset alarm and try again' on S-series); if the lamp returns to normal the alarm has cleared. If it comes back, do not keep resetting: select 'aid mode' ('Auxiliary operation' on S-series) if offered, so any electric additional heat keeps heat/hot water going, and contact your installer. Check the breakers for the heat pump, indoor module and any accessories are on at the consumer unit.
What the engineer will check
- Check communication cables and connectors between PCBs/accessory boards, DIP-switch addressing, power supply to the accessory board, and that accessories activated in the menu are actually fitted. NIBE lists: Poor connection between control board/PCB and inverter; inverter de-energised or defective; defective control board in F2040/AMS; Inverter disconnected; loose cables between inverter and base board; defective inverter board or base board in F2120; Poor connection between PCB and inverter; inverter unpowered or broken; Poor connection between PCB and inverter; inverter unpowered or broken; defective baseboard AA2; Open circuit in connection between boards; defective inverter board; defective PWB1; Open circuit in connection between boards; defective inverter board; defective control board.
Who to ask for: NIBE-trained heat pump installer (NIBE PRO / VIP).
Certification: Electrical work to BS 7671 by a competent person.
What you might notice
Sources
- TECHNICAL INFORMATION - ALARM LIST SMO 40 (TIF EN 2042-1, M12658EN) ↗ · TIF EN 2042-1 M12658EN · page 6 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026