BoilerFaultCodesTechnical description
Water temperature rising too quickly
What causes this fault?
This fault occurs when the water inside the boiler heats up far too quickly, triggering a safety sensor to prevent the unit from melting or cracking. The most common reason is a blockage or a failed pump preventing the water from flowing out of the boiler and into your radiators. It can also be caused by a build-up of sludge or debris in the system that acts like a dam, trapping heat inside the heat exchanger.
This fault is most common when turning the heating on for the first time in autumn, as circulation pumps can seize up after being inactive all summer.
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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