How can I get hot water from boiler. Heating is OK?

There is often a valve in the airing cupboard - three way valve or mid position valve.It directs the heated water to the hot water cylinder - or to the radiators - or when it's in the mid position to both.Yours may be stuck in the CH position.

This valve is often a common failure point - it has a small electric motor that drives it - they usually have a lever that sticks out to allow the valve to be hand-driven to the CH setting - check that yours has not been latched.

As a diagnostic set the timer/programmer for continual hot water and no c/h - does the boiler fire up? Is the thermostat on the hot water tank set to a reasonable setting?

If somebody operates the timer programmer alternatively between water & heating can you hear the motor operating inside the three port valve?

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Good luck...
December 2014