BoilerFaultCodesYour boiler has switched itself off because the water inside it has become too hot, which is a safety precaution to prevent damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety Thermostat Operated / overheat of the primary water
What causes this fault?
This fault occurs when the internal safety sensors detect that the water inside the boiler has reached a dangerously high temperature. It is usually caused by a failure in the pump preventing water from moving through the system or a blockage that is trapping heat within the heat exchanger.
This issue often surfaces during the first cold spell of autumn when the heating is turned back on after sitting idle all summer, which can cause the internal pump to seize.
DIY fix possible
Check that all radiator valves are fully openWait 30 minutes for the system to cool downPress the 'Reset' button on the front of the boiler
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like E110 — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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