BoilerFaultCodesYour boiler has sensed that there isn't enough water circulating inside it while the burner is on, causing it to overheat quickly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Go to Dry-Fire section of the fault finding instructions.
What causes this fault?
This fault occurs when the boiler's internal temperature rises too rapidly because water isn't moving through the heat exchanger quickly enough to carry the heat away. The most common reasons are a failed circulation pump, a blockage in the pipework, or a build-up of sludge that has restricted the flow. In some cases, it can be caused by air trapped in the system or a faulty sensor incorrectly reading the temperature.
This issue often surfaces when the heating is first turned back on in autumn, as circulation pumps can seize up after sitting idle throughout the summer months.
DIY fix possible
Check if your system pressure gauge is too low and top it up via the filling loopEnsure all radiator valves and boiler isolation valves are fully openTry bleeding your radiators to remove any trapped air pocketsReset the boiler by turning the control knob to 'Reset' for five seconds
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 Red LED: On, Green LED 1: Flash, Green LED 2: Flash — no call-out fees, no surprises.
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Potterton Promax 15/2 HE Plus is discontinued — time for a new one?
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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