Heat pumps · Error codes · Climaveneta / De Longhi Professional
Er31Climaveneta / De Longhi Professional · De'Longhi Professional / Climaveneta BWR MTD and MTD2 brine-to-water heat pump
Er31 on a Climaveneta / De Longhi Professional De'Longhi Professional / Climaveneta BWR MTD and MTD2 brine-to-water heat pump: Well / source frost prevention alarm (manual reset) - check BT3 position, source flow
Short answer
On a Climaveneta / De Longhi Professional heat pump, Er31 means: Well / source frost prevention alarm (manual reset) - check BT3 position, source flow. 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: Well / source frost prevention alarm (manual reset) - check BT3 position, source flow.
Likely causes:
- Inadequate water/brine flow, air in circuit, set-point.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
What you can check
- Note the code/LED pattern and the model from the rating plate, then contact a heat pump/refrigeration engineer.
- Check the heat pump's breaker/isolator at the consumer unit is on.
- Check the heating system pressure gauge reads in the normal range stated by the installer (usually about 1-1.5 bar cold) and that the filling loop is closed.
What the engineer will check
- Check water/brine flow, air, flow switch wiring, set-point, sensor positions.
Who to ask for: refrigeration / heat pump engineer.
Certification: Electrical competence for work inside the unit.
What you might notice
Sources
- Climaveneta WWR MTD - MTD/S, BWR MTD - MTD/S Installation and User Manual (GB 03/2010) ↗ · GB 03/2010 · page 48 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026