E008 on a Rinnai heat pump: Compressor driver limitation alarm
Short answer
On a Rinnai heat pump, E008 means: Compressor driver limitation alarm. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 24 September 2026 · 2 sources
What it means
On the HPI (HPi32) R32 monobloc
The manual says: Compressor driver limitation alarm.
Part involved: compressor inverter drive board.
When it shows: Compressor fails to reach ramp speed within 30 min.
On the R290 monobloc (HPR290)
The manual says: Forced compressor shutdown for luck of lubrication.
Part involved: compressor / refrigerant circuit.
When it shows: Compressor fails to reach ramp speed within 30 min.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: unknown.
Manual reset: manual after 3 trips per hour.
What you can check
- Note the code shown on the controller and the model number on the unit's rating label before contacting your installer.
- Check that the heat pump's isolator and consumer-unit breaker are on; do not open any casing.
What the engineer will check
On the HPI (HPi32) R32 monobloc
- Check supply voltage and phase at the unit terminals.
- Check compressor U/V/W connections and compressor winding resistance.
- Check drive board heatsink cooling and fan.
- Replace the inverter/driver board if faults persist.
Who to ask for: Heat pump engineer.
Certification: Heat pump installer competence; F-gas and flammable-refrigerant (R32/R290) handling competence for any refrigerant-circuit work.
On the R290 monobloc (HPR290)
- Record high/low pressures, discharge/suction temperatures and EEV steps with the unit running.
- Check water-side flow and air-side coil (blocked/frosted fins).
- Check pressure switches/transducers and wiring.
- Leak-test the refrigerant circuit and correct the charge (F-gas / flammable-refrigerant competent engineer only).
Who to ask for: Heat pump engineer.
Certification: Heat pump installer competence; F-gas and flammable-refrigerant (R32/R290) handling competence for any refrigerant-circuit work.
What you might notice
Sources
- Maxa i-32V5 Heat pump air/water inverters with axial fans - Controller Manual ↗ · page p.35 (MAXA i-32V5 controller manual) · Reviewed 24 September 2026
- Maxa i-290 Inverter air/water heat pumps with axial fans - Controller Manual (0106-0118) ↗ · page p.44 (MAXA i-290 controller manual) · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026