High Lockout
uP on Ideal Logic Combi ESP1

Your boiler is currently stuck in its internal computer programming mode and hasn't been set up to operate as a heater yet.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Display shows uP on power on (PCB programming mode)

What causes this fault?

This fault occurs when a newly installed or replacement control board has not been told which specific boiler model it is living in. Because the same board is used across many different models, it remains in a 'blank' programming mode and refuses to fire until the correct configuration code is entered. The most common reason is that a technician has just replaced the board but hasn't finished the final software setup.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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