BoilerFaultCodesYour boiler is displaying a status message to show the temperature it is currently trying to reach for your heating or hot water, rather than being a functional fault code.
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: Set value of flow temperature or target value of return
What causes this fault?
This message appears when the boiler is actively working to reach the specific temperature you have set on your thermostat or internal dials. It is not an error, but rather a live update showing the target heat level the system is currently aiming for to keep your home comfortable. Once the boiler reaches this target, the display will naturally update to reflect its next stage of operation.
DIY fix possible
Check your thermostat or controls are set to the desired temperatureWait for the boiler to complete its current heating cycleNo action is required as this is an informational status code
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.5 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.