HP Comms No illumination High

Ideal HP Comms No illumination Fault Code

Also written as HPCOMMSNOILLUMINATION — same fault.

The Ideal HP Comms No illumination fault code means: your smart thermostat is unable to talk to your boiler because the wired connection between them has been lost or disconnected.. It appears on 1 Ideal model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: HP Comms fault (check BSB wiring)

What causes the Ideal HP Comms No illumination fault?

This fault occurs when the physical data link between the boiler's internal computer and the smart interface is broken or interrupted. It is usually caused by a loose connection at the wiring harness or a component failure that stops the two parts from sharing information. Without this constant stream of data, the boiler cannot receive commands from your thermostat to turn the heating on.

Typical repair cost £90-180 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Ideal models that show the HP Comms No illumination fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal HP Comms No illumination 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