Heat pumps · Error codes · alpha innotec
731alpha innotec · alpha innotec, all models
731 on an alpha innotec heat pump: Timeout TDI: Temperature required for thermal disinfection could not be reached within the set switching times
Short answer
On an alpha innotec heat pump, 731 means: Timeout TDI: Temperature required for thermal disinfection could not be reached within the set switching times. The heat pump keeps running.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Timeout TDI: Temperature required for thermal disinfection could not be reached within the set switching times.
When it shows: Temperature required for thermal disinfection could not be reached within the set switching times.
Likely causes:
- Thermal disinfection setpoint not reached in time.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Information only |
| Engineer needed? | No |
The heat pump keeps running.
Resetting itself: unknown.
Manual reset: n/a.
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 thermal disinfection settings and additional heat generator.
Who to ask for: heat pump / heating engineer.
What you might notice
Sources
- Operating manual Luxtronik heating and heat pump control Part 2 (UK) 83055400lUK - 2.1 ↗ · 83055400lUK 2.1 · page 53 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026