Heat pumps · Error codes · Lämpöässä
low-pressureLämpöässä · Vsi / Vmi (ÄssäControl) GSHP with 430 l tank
low-pressure on a Lämpöässä Vsi / Vmi GSHP with 430 l tank: Low pressure switch has tripped
Short answer
On a Lämpöässä heat pump, low-pressure means: Low pressure switch has tripped. 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: Low pressure switch has tripped.
Likely causes:
- Low pressure switch has tripped.
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: acknowledge alarm on ÄssäControl screen.
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
- Test the brine circuit pump from the Maintenance menu; acknowledge the alarm (manual p.21; M8011 p.44).
Who to ask for: heat pump engineer.
Certification: F-gas certified engineer (refrigerant circuit).
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