Combi boiler problem

[adethomp]

Hi Guys n Gals

Hopefully someone out there is able to give me a bit of guidance. I have a gas fired combination boiler with a problem whereby the central heating is working ok but the hot water is not. Sometimes it will fire, sometimes not - but I get no hot water either way. Any ideas of what might cause this problem. If you need any further info, let me know.

thanks in advance for any help

Ade

[adethomp]

the boiler model is a vokera 28e.

thanks

ade