Heat pumps · Error codes · Lämpöässä
external-alarmLämpöässä · Vsi / Vmi (ÄssäControl) GSHP with 430 l tank
external-alarm on a Lämpöässä Vsi / Vmi GSHP with 430 l tank: External alarm input (DI 17 or 18) active; "fatal" status stops compressors, "info" does not (section 5.4.10)
Short answer
On a Lämpöässä heat pump, external-alarm means: External alarm input (DI 17 or 18) active; "fatal" status stops compressors, "info" does not (section 5.4.10). The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: External alarm input (DI 17 or 18) active; "fatal" status stops compressors, "info" does not (section 5.4.10).
Likely causes:
- External alarm input (DI 17 or 18) active; "fatal" status stops compressors, "info" does not (section 5.4.10).
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
What you can check
- Note the code and any text shown on the display/controller.
- Check the heat pump isolator and consumer-unit breaker are on.
What the engineer will check
- Check the external device connected to the alarm input.
Who to ask for: heat pump engineer.
Sources
- LÄMPÖÄSSÄ Vmi 6-17 Ground Source Heat Pump - Instructions for use, installation and maintenance (7/2017) ↗ · 7/2017 · page 22 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026