BoilerFaultCodesYour boiler is struggling to heat up water for your taps because the internal pump or sensor that manages hot water is not working correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Domestic hot water pump/loading fault
What causes this fault?
This fault occurs when the boiler detects that water is not being heated quickly enough for your taps, often because the internal pump has seized or failed. It can also be triggered by a buildup of limescale or debris in the heat exchanger, which restricts water flow and prevents the system from transferring heat effectively. Essentially, the boiler is shutting down because it cannot move the hot water out of the unit fast enough to avoid overheating.
This issue is more frequently reported in winter when the incoming cold water temperature drops, forcing the boiler to work harder and highlighting any existing blockages or pump weaknesses.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 F81 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Ultracom 24cx 30cx 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.
Affiliate links — we may earn a commission at no extra cost to you.