BoilerFaultCodesWhat the manual says
Manufacturer manualOverheating
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, triggering a safety sensor to cut the power. The most common reasons are a pump failure that stops water from moving or a blockage in the system that prevents heat from escaping the boiler's internal components.
This issue is more frequent during the first cold spell of autumn when pumps that have been idle all summer can seize up or struggle to circulate water.
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.
Avoid the next call-out bill
A cover plan would handle faults like F20: no call-out fees, no surprise bills.
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Related fault codes
All 52 fault codes on the Flexicom hx
Seeing a different code? Every code this model can display, in one place.