3 Way Motorised Valve causing heating issues?

Hi All!,

I have recently been having some heating issues, think I have narrowed it down to the 3 way motorised valve.

When turning on the central heating from the programmer nothing happens, boiler doesn’t even try to light. When turning on the hot water the boiler fires up and everything seems ok, but the radiators don’t heat up at all. So on the 3 way valve I turned the switch from auto to manual and the radiators heat up!

So looks like it’s down to this valve, is there any dangers in running it on manual mode until replaced? Also I am a little confused as to why the boiler is coming on for hot water, but not for central heating when selected on the programmer, is it the valve causing this?

Thanks 🙂