Heat pumps · Error codes · Alpha Heating Innovation
E178Alpha Heating Innovation · Alpha Hydro 5/8/12/16 R32 monobloc (with Pre-Plumb 200)
E178 on an Alpha Heating Innovation Alpha Hydro 5/8/12/16 R32 monobloc: Anti-Legionella cycle block not successful: Anti-Legionella cycle not completed within the pre-established time (parameter P013)
Short answer
On an Alpha Heating Innovation heat pump, E178 means: Anti-Legionella cycle block not successful: Anti-Legionella cycle not completed within the pre-established time (parameter P013). The heat pump keeps running. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Anti-Legionella cycle block not successful: Anti-Legionella cycle not completed within the pre-established time (parameter P013).
Part involved: anti-legionella / immersion.
Likely causes:
- Anti-Legionella cycle not completed within the pre-established time (parameter P013).
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump keeps running.
What you can check
- Note the code and any text shown on the display/controller.
- Check the heat pump isolator and consumer-unit breaker are on.
- Press the Reset button as the manual instructs.
What the engineer will check
- Check DHW immersion heater and parameter P013.
Who to ask for: heat pump engineer.
Sources
- Alpha Pre-Plumb 200 - Pre-plumbed cylinder with Hydro heat pump - Installation and Servicing Instructions (06-23) ↗ · Pre-Plumb 200 instructions 06-23 · page 37 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026