BoilerFaultCodesYour boiler has shut down because the water is not circulating properly, causing it to overheat too quickly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Max.water temp.: Difference between flow and return temperature too high
What causes this fault?
This fault occurs when the boiler's internal sensors detect that heat isn't leaving the unit fast enough, causing a dangerous spike in temperature. The most common reason is a failed pump that isn't pushing water around your radiators, or a blockage caused by sludge and debris that has built up inside the pipework over time.
This issue often comes to light during the first cold spell of autumn when the heating is turned back on after being idle all summer, which can cause internal pump parts to seize.
DIY fix possible
Check that your pump is running and hasn't seizedEnsure all radiator valves are fully openCheck the system pressure and top up if it is below 1.0 barBleed all radiators to remove trapped air blocks
Find a Gas Safe engineer
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Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 3 0. — no call-out fees, no surprises.
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Remeha W40 60 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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