DEFROST-TIME on a Heliotherm Basic Comfort air split: Defrosting takes too long (error message "Defrost time")
Short answer
On a Heliotherm heat pump, DEFROST-TIME means: Defrosting takes too long (error message "Defrost time"). 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: Defrosting takes too long (error message "Defrost time").
Part involved: Defrost time.
Likely causes:
- Defrost duration exceeded.
Is it safe?
Switch the heat pump off at its isolator and call an engineer.
| 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.
Manual reset: Fault clearance function in the controller main menu (web control 321 manual p.27, intended for the Heliotherm competence partner).
What you can check
- Note the error text shown on the controller and contact your Heliotherm competence partner (manual: the heat pump should be shut off and checked by a trained specialist).
- Check the outdoor evaporator is not blocked by leaves, snow or debris.
What the engineer will check
- Decrease defrost differential to increase the number of defrost cycles.
Who to ask for: heat pump / refrigeration (Heliotherm competence partner).
What you might notice
Sources
- Heliotherm Installation Instructions Air Split Heat Pump Basic Comfort Series (Version 1.0, 28.03.2019) - via ManualsLib 3389544 ↗ · Version 1.0 · page 34 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026