BoilerFaultCodesIdeal H0 Fault Code
The Ideal H0 fault code means: your indoor and outdoor units are failing to speak to each other, which has caused your heating system to stop working.. It appears on 1 Ideal model in our database.
Technical description: No connection Outdoor PCB to Indoor PCB
What causes the Ideal H0 fault?
This fault occurs when the data link between your indoor control unit and the outdoor heat pump unit is broken. The most common reason is a loose or damaged connection in the communication wiring, though it can also be caused by a power failure at the outdoor unit or a faulty circuit board preventing messages from being sent.
This fault can sometimes emerge after heavy storms or high winds if debris or moisture has caused a loose connection or damaged the exposed wiring between the units.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Ideal models that show the H0 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal H0 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026