It's actually a useful fault pattern to have, because it rules a lot out, the gas supply, ignition and main heat exchanger are all clearly doing their job.
On a combi boiler
The most likely cause is the diverter valve, which switches heated water over to the taps when you turn one on. If it sticks in the heating position, you'll get warm radiators but cold taps. A failed flow sensor or a scaled-up plate heat exchanger can give similar symptoms.
On a system or regular boiler with a cylinder
Check that the programmer is set to call for hot water and the cylinder thermostat is above 60°C. If both look right, suspect the hot water motorised valve, its actuator, or a failed immersion element on cylinders that rely on one.
Quick checks you can do yourself
Before booking someone in:
- Double-check the hot water schedule on the programmer is switched on.
- Run a bath tap on full, since some faults only show up at low flow rates.
- Note down any fault code showing on the boiler display.
Booking a repair
Diverter valves and heat exchangers sit inside the sealed part of the appliance, so this is engineer's work. If you'd rather hand it to someone qualified, we work right across Halesowen, Stourbridge, Dudley and the wider West Midlands, and we book urgent repairs in fast, usually next day.
Want it done for you?
If you want your plumbing or heating problem fixed professionally for you, contact IJS Trade Services today for fast, reliable service across the West Midlands and surrounding areas.
