BoilerFaultCodesYour boiler has detected that water is returning to the unit too hot, which usually means the water isn't circulating through your radiators properly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Return temperature too high: check system flow and pump.
What causes this fault?
This fault occurs when the water coming back into the boiler is nearly as hot as the water leaving it, indicating that heat isn't being transferred to your radiators. The most common reason is a pump failure or a blockage in the pipework that prevents the water from circulating through the house. It can also be caused by a build-up of sludge or debris inside the heat exchanger, which traps the heat inside the boiler.
This fault is more frequent in autumn when heating systems are first turned on after a long summer break, as pumps often seize up during periods of inactivity.
DIY fix possible
Ensure all radiator valves (TRVs) are fully openCheck that the central heating pump is running and not stuckBleed all radiators to remove trapped air that might be blocking water flow
Find a Gas Safe engineer
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A boiler cover plan would cover faults like E19 — 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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