H06.34 on a Baxi HP60 / Baxi Assure HP55 High Temperature Monobloc ASHP: ODU power module Outdoor unit power module is anomalous
Short answer
On a Baxi heat pump, H06.34 means: ODU power module Outdoor unit power module is anomalous. 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: ODU power module Outdoor unit power module is anomalous.
Part involved: inverter module, compressor, PFC.
Likely causes:
- The power supply voltage of the unit is low, increase the power supply voltage to the required range. The space between the units is too narrow for heat exchange. Increase the space between the units. The heat exchanger is dirty or clogged. Clean the exchanger. The fan is not running. The fan motor or the fan is broken. Replace it. The refrigerant level is too high. Adjust the quantity of refrigerant. The water flow rate is low, there is air in the system or the pump stroke is insufficient. Release the air and reselect the pump. The water outlet temperature sensor has come loose or is broken; reconnect or replace it. The wires or screws on the module are loose. Reconnect the wires and tighten the screws. The thermally conductive adhesive has dried out or has fallen off. Add a little thermally conductive adhesive. The wire connection is loose or has fallen off. Reconnect the wire. The inverter module board is faulty, replace it. If you find that there is no problem with the control system, then the compressor is faulty, replace it with a new one. The isolation valves are closed, open them.
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 outdoor unit is not blocked by leaves, debris, snow or covers and has clear airflow.
- 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
- The power supply voltage of the unit is low, increase the power supply voltage to the required range. The space between the units is too narrow for heat exchange. Increase the space between the units. The heat exchanger is dirty or clogged. Clean the exchanger. The fan is not running. The fan motor or the fan is broken. Replace it. The refrigerant level is too high. Adjust the quantity of refrigerant. The water flow rate is low, there is air in the system or the pump stroke is insufficient. Release the air and reselect the pump. The water outlet temperature sensor has come loose or is broken; reconnect or replace it. The wires or screws on the module are loose. Reconnect the wires and tighten the screws. The thermally conductive adhesive has dried out or has fallen off. Add a little thermally conductive adhesive. The wire connection is loose or has fallen off. Reconnect the wire. The inverter module board is faulty, replace it. If you find that there is no problem with the control system, then the compressor is faulty, replace it with a new one. The isolation valves are closed, open them.
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 130 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026