284 on a NIBE heat pump: Temperature limiter alarm for defrost element: Temperature limiter FD3 has tripped
Short answer
On a NIBE heat pump, 284 means: Temperature limiter alarm for defrost element: Temperature limiter FD3 has tripped. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
0 sources
What it means
The manual says: Temperature limiter alarm for defrost element: Temperature limiter FD3 has tripped.
Part involved: evaporator defrost.
When it shows: Temperature limiter FD3 has tripped.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: no/unknown - Heat pump changes to passive defrost.
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 outdoor unit is not blocked by leaves, snow or ice and that nothing obstructs the airflow.
What the engineer will check
- Check system volume and flow during defrost, particle filter, circulation pump, evaporator airflow, evaporator/defrost sensors and refrigerant circuit.
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
A code explains what the controller detected, not a confirmed root cause.