I can only get hot water if I switch the central heating on permanantly. Even if I just set the boiler for hot water only,it still doesn't work. The boiler is about 10 years old, is it worth repairing or just replace it? Thanks.
Possible cause of fault can be with DHW thermistor or diverter valve that would be cheaper than replacing the boiler, although combi boiler that over ten years old are normally on borrowed time before they require replacing.