025 on an iDM Energiesysteme TERRA SW: High pressure fault - lockout: The high-pressure monitor has switched the heat pump off (> 3 times in 24 h). The heat pump is no longer operated
Short answer
On an iDM Energiesysteme heat pump, 025 means: High pressure fault - lockout: The high-pressure monitor has switched the heat pump off (> 3 times in 24 h). The heat pump is no longer operated. 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: High pressure fault - lockout: The high-pressure monitor has switched the heat pump off (> 3 times in 24 h). The heat pump is no longer operated.
Part involved: High pressure fault - lockout.
When it shows: The high-pressure monitor has switched the heat pump off (> 3 times in 24 h). The heat pump is no longer operated.
Is it safe?
Switch the heat pump off at its isolator and call an engineer.
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Safety lockout |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Manual reset: Unlock/acknowledge via Navigator (max. once after 023); call service.
What you can check
- Note the fault number and text shown after tapping the fault symbol on the Navigator display. This is a locking (Verriegelung) fault - iDM says to call customer service; do not repeatedly unlock it (after fault 023 the unit may be unlocked at most once).
What the engineer will check
- Diagnose per iDM service documentation for the unit (not obtained): check the monitored circuit/component named in the fault.
Who to ask for: heat pump engineer.
Certification: F-Gas category I certificate (refrigerant circuit work).
What you might notice
Sources
- IDM Wärmepumpen mit Navigatorregelung 2.0 - Bedienungsanleitung (812152 Rev.3) ↗ · 812152 Rev.3 · page p.70 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026