Should CH pump come on when HW is on?

[KeenAmateurUK]

Hi, I'm not too experienced with heating systems, but our central heating pump is running when the hot water is being commanded from the controller, even if the heating is not turned on. It's making quite a racket (and getting quite warm).

On a possibly related note, the Drayton mid-position valve has stopped moving automatically to the 'heating' position - I can manually push it over using the lever, but this is the only way I can get the heating to turn on.

Do you think replacing the mid-position valve might fix my problems?

EDIT: I forgot to point out that although the CH pump is running, the radiators are not heating up unless I separately turn on the CH at the controller and then manually move the mid-position valve.

 

[Madrab]

Yes, change the mid position valve's actuator to start with.

If you have a fully pumped system, which it should be if you have a Y plan (mid pos valve) then the pump will run when either HW or CH is called for as it needs to pump the hot water around the system be it the cylinder's coil or out to the rads.

 

[oilhead]

Yes, change the mid position valve's actuator to start with.

If you have a fully pumped system, which it should be if you have a Y plan (mid pos valve) then the pump will run when either HW or CH is called for as it needs to pump the hot water around the system be it the cylinder's coil or out to the rads.

Or you could just change the synchron motor. Availableas a Drayton spare and just requires one screw releasing and two spade connections. Make sure you get the Drayton one and not a cheap copy. Screwfix stock the right one