029 on an iDM Energiesysteme TERRA SW: Soft starter 1 - lockout: Soft-starter fault (> 5 times in 24 h). The heat pump is no longer operated
Short answer
On an iDM Energiesysteme heat pump, 029 means: Soft starter 1 - lockout: Soft-starter fault (> 5 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: Soft starter 1 - lockout: Soft-starter fault (> 5 times in 24 h). The heat pump is no longer operated.
Part involved: Soft starter 1 - lockout.
When it shows: Soft-starter fault (> 5 times in 24 h). The heat pump is no longer operated.
Is it safe?
| 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. Check the heat pump's breaker/isolator at the consumer unit is on and has not tripped. 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: Qualified electrician / heat pump engineer (electrical fault-finding).
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