High
FU on Ideal Compact

Your boiler has detected that the water is heating up too quickly or not circulating properly, which usually means the water flow is blocked.

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

Difference greater than 50c – check isolation valves are open

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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