916 on a NIBE heat pump: Sensor fault: BT16 evaporator sensor (exhaust air module): BT16 in exhaust air module unreasonable value for longer than 2 s
Short answer
On a NIBE heat pump, 916 means: Sensor fault: BT16 evaporator sensor (exhaust air module): BT16 in exhaust air module unreasonable value for longer than 2 s. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Sensor fault: BT16 evaporator sensor (exhaust air module): BT16 in exhaust air module unreasonable value for longer than 2 s.
Part involved: fans, air filters, air sensors.
When it shows: BT16 in exhaust air module unreasonable value for longer than 2 s.
Likely causes:
- Open circuit or short circuit on sensor input; defective sensor.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: yes - Automatic reset after 60 s communication.
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 exhaust air valves/grilles in the rooms are open and not blocked; check the filter reminder in the user manual maintenance section.
What the engineer will check
- Check ventilation airflow, fans, filters, air sensors and condensate drainage/level monitor. NIBE lists: Open circuit or short circuit on sensor input; defective sensor.
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.
What you might notice
Sources
- TECHNICAL INFORMATION - ALARM LIST SMO 40 (TIF EN 2042-1, M12658EN) ↗ · TIF EN 2042-1 M12658EN · page 13 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026