Heat pumps · Error codes · Grant
L8Grant
L8 on a Grant heat pump: Room temp. (Master Remote controller) error
Short answer
On a Grant heat pump, L8 means: Room temp. (Master Remote controller) error. The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 2 sources
What it means
The manual says: Room temp. (Master Remote controller) error.
Part involved: room sensor in master remote controller.
Likely causes:
- Room temperature sensor in master remote controller faulty.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: Yes (Chofu 'Auto').
Manual reset: Not required (auto).
What you can check
- Note the exact code shown on the controller display and tell your installer or Grant-trained engineer.
- Grant advises homeowners NOT to reset Aerona3 fault codes themselves - leave the reset to the engineer.
What the engineer will check
- Master remote controller should be replaced.
Who to ask for: Grant-trained heat pump engineer.
What you might notice
What owners and engineers report
9 owner and engineer reports mention this.
- Controller / thermostat problem on the Aerona³ R32: 9 reports
Sources
- Chofu Service Manual AEYC-0643XU-CH / 1043XU-CH / 1242XU-CH / 1643XU-CH (RA-98(5)) - Air to Water Heat Pump, Monobloc DC Inverter ↗ · RA-98(5) · page 31 · Reviewed 23 September 2026
- Chofu AEYC-0639U-CH / AEYC-1039U-CH / AEYC-1639U-CH Installation and Instruction Manual (R410A) ↗ · Chofu AEYC-0639U/1039U/1639U-CH Installation and Instruction Manual (ManualsLib-derived copy) · page 146 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026