BoilerFaultCodesIdeal Hd Fault Code
Also written as HD — same fault.
The Ideal Hd fault code means: your main heat pump unit is unable to talk to the secondary unit, meaning the system cannot coordinate properly to heat your home.. It appears on 1 Ideal model in our database.
Technical description: No connection Master Heat Pump to Slave Heat Pump
What causes the Ideal Hd fault?
This fault occurs when the electrical link between the two main heating units is broken, preventing them from sharing data. The most common reasons are a loose or damaged communication cable, or a failure in the electronic control boards that manage the system's signals.
This fault can sometimes occur after periods of heavy rain or storms if moisture enters the external wiring enclosures and interferes with the communication signal.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Search the official register for a qualified engineer in your area.
Gas Safe Register →Ideal models that show the Hd fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal Hd 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