712 on an alpha innotec heat pump: Domestic hot water sensor. Please call installer: Break or short circuit in the domestic hot water sensor. No fault shutdown
Short answer
On an alpha innotec heat pump, 712 means: Domestic hot water sensor. Please call installer: Break or short circuit in the domestic hot water sensor. No fault shutdown. 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: Domestic hot water sensor. Please call installer: Break or short circuit in the domestic hot water sensor. No fault shutdown.
When it shows: Break or short circuit in the domestic hot water sensor. No fault shutdown.
Likely causes:
- DHW sensor defective.
- Plug/cable fault.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: no.
Manual reset: none - no fault shutdown.
What you can check
- Note the error number and text shown on the Luxtronik display.
- Acknowledge the message by pressing the rotary pushbutton for about 7 seconds (as the Luxtronik manual permits); if the same error reappears, contact your installer or ait customer service with the error number.
- Check the heat pump breakers/isolator at the consumer unit are on (do not open any casing).
What the engineer will check
- Check domestic hot water sensor, plug and connection line.
Who to ask for: heat pump service engineer (electrical/controls).
What you might notice
Sources
- Operating manual Luxtronik heating and heat pump control Part 2 (UK) 83055400lUK - 2.1 ↗ · 83055400lUK 2.1 · page 52 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026