H06.69 on a Baxi HP60 / Baxi Assure HP55 High Temperature Monobloc ASHP: 3 phase sequence Invalid phase sequence in the 3 phase heat pump power supply
Short answer
On a Baxi heat pump, H06.69 means: 3 phase sequence Invalid phase sequence in the 3 phase heat pump power supply. The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: 3 phase sequence Invalid phase sequence in the 3 phase heat pump power supply.
Part involved: power supply / PCB.
Likely causes:
- Check that the power supply cables are correctly connected and avoid phase loss. Check whether the connections of the neutral and live wires have been reversed.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: yes - system restarts automatically when the cause disappears (may run in degraded/back-up mode meanwhile).
Manual reset: not required once cause removed.
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).
- The manual's user steps allow switching the system off and on once to see if the error clears; if the code returns, contact the installer.
- If the code persists or returns, contact a heat pump engineer.
What the engineer will check
- Check that the power supply cables are correctly connected and avoid phase loss. Check whether the connections of the neutral and live wires have been reversed.
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, user and service manual - Indoor unit ASHP Control ↗ · 7887625 - v04 - 22072025 · page 132 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026