Heat pumps · Error codes · IVT
GT10IVT · Greenline HT Plus
GT10 on an IVT Greenline HT Plus: HTF in under limit T10 (GT10): brine (heat transfer fluid) temperature into the heat pump below the limit
Short answer
On an IVT heat pump, GT10 means: HTF in under limit T10 (GT10): brine (heat transfer fluid) temperature into the heat pump below the limit. 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: HTF in under limit T10 (GT10): brine (heat transfer fluid) temperature into the heat pump below the limit.
Part involved: brine-in sensor GT10.
Likely causes:
- Temporarily low brine temperature; too low flow on the cold side (dirty particle filter); minimum brine temperature set too low; groundwater systems: clogged filter, tripped groundwater pump cut-out/fuse, faulty groundwater pump.
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: Yes.
What you can check
- Wait and see - if the alarm returns, contact your dealer. Look at the brine expansion tank: the fluid level should be visible (user guide check). Do not refill or open the ground-loop circuit yourself - call the installer.
What the engineer will check
- Clean cold-side particle filter; check brine flow and minimum temperature setting; for groundwater check filter, pump and its protection.
Who to ask for: heat pump engineer.
What you might notice
Sources
- Greenline HT Plus C and E Guide to installation, commissioning and maintenance (Art. no 290410-29, v1.1) ↗ · 290410-29 v1.1 · page p.39 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026