Heat pumps · Error codes · Grant
PP7Grant · Aerona (1st generation)
PP7 on a Grant Aerona: Winter anti-freeze protection in operation
Short answer
On a Grant heat pump, PP7 means: Winter anti-freeze protection in operation. The heat pump keeps running.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Winter anti-freeze protection in operation.
Part involved: frost protection function.
When it shows: Shown on the ATC controller display.
Likely causes:
- Frost protection active (not a fault).
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Information only |
| Engineer needed? | No |
The heat pump keeps running.
Resetting itself: Not stated.
Manual reset: Not stated.
What you can check
- Note the exact code shown on the controller display and tell your installer or Grant-trained engineer.
- Check the heat pump isolator switch and the consumer-unit breaker/RCD for the heat pump are ON (do not repeatedly reset a tripping breaker).
- No action needed - frost protection is operating normally; do not switch the heat pump off at the isolator in cold weather.
What the engineer will check
Who to ask for: Heat pump engineer.
Sources
- Grant Aerona Air Source Heat Pump - Air to Water Heat Pump Range - Installation & User Instructions (DOC.87) ↗ · Rev.05 · page 37 (PDF p41); s13.5-13.6 p36 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026