E27 on an Alpha Heating Innovation Alpha Hydro 5/8/12/16 R32 monobloc: Circulation insufficient: Overheating in the indoor unit due to insufficient water circulating in the primary circuit: low system circulation (closed shut-off devices, air in system), pump blocked, damaged flowmeter
Short answer
On an Alpha Heating Innovation heat pump, E27 means: Circulation insufficient: Overheating in the indoor unit due to insufficient water circulating in the primary circuit: low system circulation (closed shut-off devices, air in system), pump blocked, damaged flowmeter. 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: Circulation insufficient: Overheating in the indoor unit due to insufficient water circulating in the primary circuit: low system circulation (closed shut-off devices, air in system), pump blocked, damaged flowmeter.
Part involved: primary circuit / pump / flowmeter.
Likely causes:
- Overheating in the indoor unit due to insufficient water circulating in the primary circuit: low system circulation (closed shut-off devices, air in system), pump blocked, damaged flowmeter.
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 and any text shown on the display/controller.
- Check the heat pump isolator and consumer-unit breaker are on.
- Press the Reset button once, as the manual instructs.
- Check the system pressure gauge reading.
What the engineer will check
- Check no shut-off valves are closed and the system is de-aerated.
- Free the pump if blocked.
- Check flowmeter.
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 36 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026