Central heating issue

[paul bing]

Vailant ecotec system boiler. Drayton Lifestyle controller

Hi. Yesterday I turned on my central heating. After turning it at the controller off I noticed it was still running. The hot water was set to 'timer' (but wasn't on at that time) When I turned the hot water to 'off' the boiler stopped & the central heating went off. I turned the HW back on to 'Timer'. This morning, when the HW was running during its timed programme, the rads got hot.

Could anyone point me in the direction of the possible cause for this? I'm thinking sticking zone valve at the HW cylinder but really have no idea. Could it be this, or an issue with the Drayton controller?

Thanks in advance for any replies.

 

[SimonG]

Sticking 2 port or misbehaving 3 port.

2 port either sticking or micro switch in head stuck closed.

 

[paul bing]

Sticking 2 port or misbehaving 3 port.

2 port either sticking or micro switch in head stuck closed.

Thanks for that. The black manual switch on the body of the actuator is 'floppy' (no resistance) I read somewhere that this indicates the unit is stuck in mid position, supplying both HW & CH at the same time. Is this correct? I've attached a photo for reference

Mm, it seems the photo hasn't loaded? The unit is a Drayton mid position actuator MA1