D.1 Low
Your boiler is not broken; it is simply continuing to run the internal pump for a few minutes to safely cool down the heat exchanger after providing heating or hot water.
Technical description: Water pump overrun – time for heat mode
Typical repair cost: £0 (including labour)
DIY fix possible
Wait for 5 to 10 minutesCheck if the display changes once the cooling cycle finishesEnsure your room thermostat is turned down if you want the pump to stop sooner
Protect yourself from future repair bills
A boiler cover plan would cover faults like D.1 — no call-out fees, no surprises.
*Affiliate links — we may earn a commission at no extra cost to you. Prices shown are starting prices.