Hi, Ive already got a few answers from this forum for a few problems I've got with the CH. It appears that the actuaor is the cause of why I get the heating on when only hot water is needed - question is, how easy is it to change the actuator sat on top of the three way valve ?? Is this something I could attempt ( reckon I'm about a 7 on the DIY scale ).
Just changing the actuator - all you need is the electrical supply turned off.
If you need to change the valve/body - you will need to drain the system, they're normally ok though and it's just the actuator/motorised valve that needs changing.