F43-F47 on a Dimplex A-Class air source heat pump: F43-F47 error messages are defrost errors (A-Class controller)
Short answer
On a Dimplex heat pump, F43-F47 means: F43-F47 error messages are defrost errors (A-Class controller). The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: F43-F47 error messages are defrost errors (A-Class controller).
Part involved: Defrost / condenser plate heat exchanger.
When it shows: Service-menu note: heating water return >= 18C required for proper defrost.
Likely causes:
- Defrost failure; water flow temperature too low (condenser plate heat exchanger may freeze).
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Manual reset: If a major fault occurs many times the compressor locks out: power to the compressor must be off at least 2 minutes and back on (Issue 1.05 p.31).
What you can check
- Read the error code from the message list (login 998 > Message list) and give it to the installer.
- Check the outdoor unit is not blocked by snow or debris.
- Check the system pressure gauge reading.
What the engineer will check
- Check return temperature >= 18C during defrost.
- Check flow rate, strainer, buffer isolation.
- Manual defrost only by trained installers.
Who to ask for: heat pump service engineer.
Certification: F-Gas (refrigerant handling) certification for any refrigerant-circuit work.
What you might notice
Sources
- A Class Air Source Heat Pump A8M / A12M / A16M Installation Manual 8/60472/0 Issue 1.05 ↗ · 8/60472/0 Issue 1.05 · page 32 (PDF p.35) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026