995 on a NIBE heat pump: External alarm: An alarm according to function chosen on the AUX input [other NIBE documents: Alarm according to selected function on AUX input]
Short answer
On a NIBE heat pump, 995 means: External alarm: An alarm according to function chosen on the AUX input [other NIBE documents: Alarm according to selected function on AUX input]. The heat pump keeps running.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: External alarm: An alarm according to function chosen on the AUX input [other NIBE documents: Alarm according to selected function on AUX input].
Part involved: AUX input / external control.
When it shows: An alarm according to function chosen on the AUX input; Alarm according to selected function on AUX input.
Likely causes:
- External equipment connected to AUX input gives an alarm.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Information only |
The heat pump keeps running.
Resetting itself: yes - Information only; automatic reset when input opens; None.
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 whether any external equipment connected to the heat pump (e.g. energy supplier load control, smart thermostat or other AUX device) is signalling a block.
What the engineer will check
- Check the device connected to the AUX input and the AUX input configuration. NIBE lists: External equipment connected to AUX input gives an alarm.
Who to ask for: NIBE-trained heat pump installer (NIBE PRO / VIP).
Certification: None specific beyond competent heat pump installer; electrical work to BS 7671.
Sources
- TECHNICAL INFORMATION - ALARM LIST SMO 40 (TIF EN 2042-1, M12658EN) ↗ · TIF EN 2042-1 M12658EN · page 21 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026