D4 286 High
Your boiler has shut down because it thinks the water returning to the unit is dangerously hot, which usually means water isn't circulating through your radiators properly.
Technical description: The boiler return temperature sensor has detected a return temperature higher than 105°c
Typical repair cost: £180-450 (including labour)
DIY fix possible
Check that all radiator valves are fully open.Ensure the central heating pump is running and hasn't seized.Bleed all radiators to remove trapped air that might be blocking water flow.
Protect yourself from future repair bills
A boiler cover plan would cover faults like D4 286 — no call-out fees, no surprises.
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Parts commonly replaced
- Circulation pump
- Return temperature sensor (NTC)
- Main heat exchanger (flushing/cleaning)
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