Heat pumps · Error codes · Alpha Heating Innovation
E189Alpha Heating Innovation · Alpha Hydro 5/8/12/16 R32 monobloc (with Pre-Plumb 200)
E189 on an Alpha Heating Innovation Alpha Hydro 5/8/12/16 R32 monobloc: Time out alarm with communication board: Communication between the printed circuit boards is lost; system does not start
Short answer
On an Alpha Heating Innovation heat pump, E189 means: Time out alarm with communication board: Communication between the printed circuit boards is lost; system does not start. 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: Time out alarm with communication board: Communication between the printed circuit boards is lost; system does not start.
Part involved: PCB / interface board.
Likely causes:
- Communication between the printed circuit boards is lost; system does not start.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
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.
What the engineer will check
- Check communication between the PCB and the interface board.
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