026 on an iDM Energiesysteme TERRA SW: Flow monitoring / pressure monitoring: The flow switch on groundwater systems has switched the heat pump off (< 3 times in 24 h)
Short answer
On an iDM Energiesysteme heat pump, 026 means: Flow monitoring / pressure monitoring: The flow switch on groundwater systems has switched the heat pump off (< 3 times in 24 h). 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: Flow monitoring / pressure monitoring: The flow switch on groundwater systems has switched the heat pump off (< 3 times in 24 h).
Part involved: Flow monitoring / pressure monitoring.
When it shows: The flow switch on groundwater systems has switched the heat pump off (< 3 times in 24 h).
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.
Resetting itself: Counts towards 24 h lockout thresholds.
What you can check
- Note the fault number and text shown after tapping the fault symbol on the Navigator display. Look at the brine/heat-source expansion vessel or pressure gauge: the fluid level should be visible (user guide check). Do not refill or open the ground-loop circuit yourself - call the installer. 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: 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