Mid Position Valve ACL

[motorbiking]

I think my mid-position valve has packed up as the boiler is only driving the hot water at the moment and the boiler keeps powering down, despite rads being cold. I've put it in the manual open position for now, which seems to work as a temp fix.

I'm not being tight, but don't really want to drain the system anytime soon.

Is there a way to test the motor?

I'm assuming these are 230v AC motors, so I could put a test meter on the supply to see if its getting power. Does the valve open when the controls are on (e.g. HW, heating). i.e. pressing the override for hw and heat should activate the control?

Are these heads a standard fitting? could I buy a new one and just fit the new head and not replace the valve?

Or if I have to bite the bullet, are they all the same size, i.e. a new valve will fit in the same space?

I have an ACL Lifestyle valve, looks like this:

 

[Echo the husky]

If heating is switched on you should have 240V across the blue and white (or brown) wire. Some of the older ACL valves require replacement of the entire thing, the newer style the head unclips by pressing the little rectangle black button on the long side, and you can buy a replacement head. The motor is also available as a spare.

 

[ianmcd]

If all working when you manually open the valve most likely just the synchron motor needing replaced and no need to drain anything

 

[motorbiking]

thanks - I will try that first

 

[ianmcd]

easy enough job to do just make sure you isolate the supply and dont just turn it off at the programmer as there is a constant supply in there so isolate it at the spur before you start.

 

[cross thread]

when you remove the head give it a shake if you hear a bit rattling round a locating peg snaps off inside that holds the motor

 

[flameport]

Does the valve open when the controls are on (e.g. HW, heating). i.e. pressing the override for hw and heat should activate the control?

The default position with no power is HW, the motor moves it to both or CH only, so if the motor fails, HW is all you will get.

Are these heads a standard fitting? could I buy a new one and just fit the new head and not replace the valve?

That type is still available, the head just clips onto the valve, so can be replaced easily.
You can buy the head separately, but it is often little difference in buying the whole thing.

The motor inside can be replaced if you can be bothered, but the rest is plastic and pieces can and do break off.

 

[motorbiking]

So I fixed it for under £15 in the end..
https://www.toolstation.com/shop/p68222

The only problem is the supplied spade connectors weren't the right shape, so I just twisted them on and put a dob of glue gun glue to hold them there until I get round to buying some spade terminals that fit. thanks again for the help. Only took 5 mins in the end.