Heat pumps · Error codes · Firebird
81Firebird · Enviroair (Hitachi Yutaki M based) 7.5-16kW monobloc
81 on a Firebird Enviroair 7.5-16kW monobloc: 'Momentary power interruption' or 'Low voltage detected'
Short answer
On a Firebird heat pump, 81 means: 'Momentary power interruption' or 'Low voltage detected'. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: 'Momentary power interruption' or 'Low voltage detected'.
Part involved: compressor driver / inverter board.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: Unit retries up to three times before stopping.
What you can check
- Note the exact code shown on the controller (a photo helps) and report it to your installer or the manufacturer's service line.
- Check the heat pump's supply breaker/isolator at the consumer unit is on (do not open any casing).
- If the controller shows red/alarm, the Firebird Enviroair Hitachi end-user guide allows a reset by pressing the ON button for 3 seconds and again; if it goes red again, contact your engineer.
What the engineer will check
- Refer to Hitachi Yutaki M service documentation.
Who to ask for: heat pump electrical / inverter.
Certification: Electrical competence; manufacturer-trained heat pump engineer.
What you might notice
Sources
- Firebird Enviroair Air Source Heat Pumps - Installation & Operation Manual (Enviroair 7.5/11/14/16kW, R410A monobloc) ↗ · Dec 2017 · page 53 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026