Heat pumps · Error codes · iDM Energiesysteme
021iDM Energiesysteme · TERRA SW (2013)
021 on an iDM Energiesysteme TERRA SW: Heat pump flow minimum temperature: Heat pump flow temperature is below the set minimum temperature
Short answer
On an iDM Energiesysteme heat pump, 021 means: Heat pump flow minimum temperature: Heat pump flow temperature is below the set minimum temperature. 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: Heat pump flow minimum temperature: Heat pump flow temperature is below the set minimum temperature.
Part involved: Heat pump flow minimum temperature.
When it shows: Heat pump flow temperature is below the set minimum temperature.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
What you can check
- Note the fault number and text shown after tapping the fault symbol on the Navigator display. Check the heating-system pressure gauge is in the range given in the user guide - do not top up yourself unless you have been shown how; check radiator/underfloor valves and room thermostats are open. 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.
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