BoilerFaultCodes D Low Information
Your boiler is working normally and is currently heating up water for your taps or shower.
Monitor it
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Boiler is active for domestic hot water.
What causes this fault?
This is not actually a fault, but a status indicator showing the boiler is responding to a demand for hot water. It occurs when you turn on a tap or shower, triggering the internal flow sensor to tell the boiler to fire up and heat the water. Once you turn the tap off, the display will change back to its normal standby mode.
Typical repair cost £0 (including labour)
DIY fix possible
This fault may be fixable without an engineer. Check your manual first.
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 D — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.