Heat pumps · Error codes · Kronoterm
MODULE-INV-ALARMKronoterm · TERMOTRONIC-controlled heat pumps (legacy WP / WPL / WPLV water-water, brine-water, air-water)
MODULE-INV-ALARM on a Kronoterm TERMOTRONIC-controlled heat pumps: No connection with the external device (inverter)
Short answer
On a Kronoterm heat pump, MODULE-INV-ALARM means: No connection with the external device (inverter). 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: No connection with the external device (inverter).
Part involved: inverter drive communication.
Likely causes:
- Communication loss with external device.
Is it safe?
| 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: After fixing the cause restart by holding ENTER for 3 s.
What you can check
- Note the exact message shown on the TERMOTRONIC display.
What the engineer will check
- Authorised service.
Who to ask for: heat pump engineer.
What you might notice
Sources
- KRONOTERM Owner's manual for heat pumps water-water, brine-water and air-water (TERMOTRONIC controller), Id 17-16-19-2972-05 ↗ · 17-16-19-2972-05 · page 53 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026