074 on an iDM Energiesysteme TERRA SW: Soft starter 2 (see LED): Soft-starter fault on the second compressor; type of fault shown on the soft starter
Short answer
On an iDM Energiesysteme heat pump, 074 means: Soft starter 2 (see LED): Soft-starter fault on the second compressor; type of fault shown on the soft starter. 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: Soft starter 2 (see LED): Soft-starter fault on the second compressor; type of fault shown on the soft starter.
Part involved: Soft starter 2 (see LED).
When it shows: Soft-starter fault on the second compressor; type of fault shown on the soft starter.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
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. If the fault recurs several times, contact iDM customer service/your installer.
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.71 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026