Hot water but no heating

[bward]

I have just moved into a property with water cylinder and boiler (i.e. not a combination boiler). Using the controls I can only get hot water but no central heating. If I put the heating system to central heating only the three-port valve does not move over to switch the water flow. If I manually change the three-port valve (Honeywell) I can get central heating, but only if I set the controls to hot water only. If I set the controls to central heating only I get nothing, even when I turn the valve manually. Does anybody know if this is likely to be a faulty valve or is it possible that the timer / control unit has gone? Also, is this something I can fix myself or is it a job for an engineer?

Thanks very much.

[htg engineer]

More than likely it'll be the actuator/motorised head.

Buy the same model, swap over one wire at a time. Shouldn't cause you any problems.

ISOLATE ELECTRICITY SUPPLY

Htg