EE on a Baxi heat pump: Main control board of hydraulic module EEprom failure
Short answer
On a Baxi heat pump, EE means: Main control board of hydraulic module EEprom failure. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 2 sources
What it means
On the Assure Monobloc ASHP (Assure Mono 5/7/9/12/16)
The manual says: Main control board of hydraulic module EEprom failure.
Part involved: power supply / PCB.
Likely causes:
- EEprom parameter error - rewrite; EEprom chip failing - replace; hydraulic module main control board broken - replace PCB.
On the HP40 / Baxi Assure HP50 Monobloc ASHP
The manual says: Hydraulic module EEprom failure.
Part involved: power supply / PCB.
Likely causes:
- EEprom parameter error - rewrite EEprom data; EEprom chip broken - replace; hydraulic module main control board broken - replace PCB.
Is it safe?
On the Assure Monobloc ASHP (Assure Mono 5/7/9/12/16)
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: unknown.
Manual reset: Power OFF/ON after correcting cause (ISM 13.4).
On the HP40 / Baxi Assure HP50 Monobloc ASHP
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: unknown.
Manual reset: Installer: correct cause then power OFF/ON (ISM 13.4).
What you can check
- Note the exact code shown on the controller and when it appeared.
- Check the heat pump's consumer-unit breaker / isolator is on (do not open any panels).
- If the code persists or returns, contact a heat pump engineer.
What the engineer will check
On the Assure Monobloc ASHP (Assure Mono 5/7/9/12/16)
- EEprom parameter error - rewrite; EEprom chip failing - replace; hydraulic module main control board broken - replace PCB.
Who to ask for: heat pump engineer with electrical competence.
Certification: Qualified electrician / manufacturer-trained heat pump engineer; F-gas if refrigerant circuit is opened.
On the HP40 / Baxi Assure HP50 Monobloc ASHP
- EEprom parameter error - rewrite EEprom data; EEprom chip broken - replace; hydraulic module main control board broken - replace PCB.
Who to ask for: heat pump engineer with electrical competence.
Certification: Qualified electrician / manufacturer-trained heat pump engineer; F-gas if refrigerant circuit is opened.
What you might notice
Sources
- Installation and owner's manual - Heat Pump air/water 'inverter' Assure Mono 5, 7, 9, 12, 16 ↗ · Back cover shows '7762758 - v05 - 19082020' (same number as the Assure Split manual - probably shared back-cover artwork) · page 72 · Reviewed 23 September 2026
- Installation and Service Manual - Heat Pump air/water 'inverter' HP40/50-4-1PHMB to HP40/50-13-3PHMB (United Kingdom) ↗ · 784570-01 (v1) · page 73 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026