Boiler works for heating but no hot water
Radiators warm but taps cold usually points one way on a combi: the diverter valve.
What it actually means
A combi boiler decides where to send heat with a diverter valve. When that valve sticks or wears, you often get one service but not the other: heating fine, hot taps cold, or the reverse.
Before blaming the valve, rule out the simple stuff: temperature settings turned down, a summer or eco mode, or a scale-clogged plate heat exchanger in hard water areas.
Try this first, before you spend a penny
- 1
Check the hot water temperature setting
It sounds daft, but a knocked dial or an eco mode is a free fix.
- 2
Run the hot tap wide open for a minute
A sticky diverter sometimes shifts with full flow demand.
- 3
Check pressure and any fault codes
Low pressure or a code changes the diagnosis: look that code up instead.
When it is a pro job
A worn diverter valve or scaled-up plate heat exchanger needs an engineer. Both are routine jobs with the case open, which is Gas Safe work.
Gas Safe registered heating engineer
Typical UK range for a diverter valve or plate heat exchanger job on a combi, parts included. Exact price depends on your model.
£150 to £400
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