No illumination (HP Comms) High

Ideal No illumination (HP Comms) Fault Code

Also written as NOILLUMINATIONHPCOMMS — same fault.

The Ideal No illumination (HP Comms) fault code means: your smart thermostat display is blank because it has lost its wired connection to the heat pump or boiler interface, preventing you from controlling your heating.. 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 No illumination (HP Comms) fault?

This fault occurs when the physical data link between your smart thermostat's base and the heating appliance is broken or disconnected. The most common reason is a loose wire or a poor connection at the terminals, which prevents the screen from receiving the power and digital information it needs to function.

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 No illumination (HP Comms) fault code

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

Source

Ideal No illumination (HP Comms) 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