Motorised valve allowing water flow even though spindle closed

[Barry Clark]

hi. I removed actuator from motorised valve. Spindle at 12 noon so valve should be closed. However hot is flowing through the valve. I can manually turn the spindle about 20 degrees. Is it possible the gland inside is not turning even though spindle is? Many thanks.

 

[Chuck]

hi. I removed actuator from motorised valve. Spindle at 12 noon so valve should be closed. However hot is flowing through the valve. I can manually turn the spindle about 20 degrees. Is it possible the gland inside is not turning even though spindle is? Many thanks.

What model valve?

The most common ones IME are Honeywell and the ones I've dismantled have a 'rubber' ball on a crank that is rolled in front of the outlet to close the valve. It's a neat design that works well until it doesn't. You should be able to rotate the shaft with your fingers and 20° is about the normal range. Usual failure mode is the ball gets a dent in it and stops sealing reliably. You can buy a repair kit for about a tenner but I suspect that most people just replace the valve so the customer feels they've got something for their money most of which goes on the time to drain, refill and bleed the system. And then there's the Fernox tax...

 

[Chuck]

Oops, clicked wrong button.

 

[ShaunCorbs]

time for a new valve and body

finding there only lasting 5-10 years (decent valve) could be less

 

[Barry Clark]

What model valve?

The most common ones IME are Honeywell and the ones I've dismantled have a 'rubber' ball on a crank that is rolled in front of the outlet to close the valve. It's a neat design that works well until it doesn't. You should be able to rotate the shaft with your fingers and 20° is about the normal range. Usual failure mode is the ball gets a dent in it and stops sealing reliably. You can buy a repair kit for about a tenner but I suspect that most people just replace the valve so the customer feels they've got something for their money most of which goes on the time to drain, refill and bleed the system. And then there's the Fernox tax...

Thanks for quick response. It appears to be an older Drayton. It only says BGMVSP-2 on label but this Drayton replacement fits it perfectly: http://www.NoLinkingToThis/p/drayton-zone-replacement-valve-actuator/76959?_requestid=445491
I fitted it but still problem, hence my asking if it's possible the valve is damaged internally. The spindle turns but it never shuts off and from what you say it sounds like it's leaking even though closed.

 

[ShaunCorbs]

drayton have a flapper, you will need to hold it in the shut position (as the flow will open it without the head on)

and tbh heads on there own arnt worth it, its only another £10 or less if your in the trade (about 38 + vat)

 

[Barry Clark]

Ok. But even with the new head on it's still allowing hot water to flow to the CH if there is demand from the HW cylinder, so I guess it's leaking internally even though held closed by the actuator. It's mounted horizontally and is under the floor (had to take up floor tiles and boards to find) and it's at the lowest point of the system. Guess it could be silted up and so not closing fully? Will have to drain and replace with a new unit. Screwfix said they'd refund the head only. Thanks for your help.

 

[ShaunCorbs]

Ok. But even with the new head on it's still allowing hot water to flow to the CH if there is demand from the HW cylinder, so I guess it's leaking internally even though held closed by the actuator. It's mounted horizontally and is under the floor (had to take up floor tiles and boards to find) and it's at the lowest point of the system. Guess it could be silted up and so not closing fully? Will have to drain and replace with a new unit. Screwfix said they'd refund the head only. Thanks for your help.

yea tbh normally best to change the body as well unless its under 5 years old, and thats good of them

 

[Barry Clark]

Sorry, just had a thought. There is a small black lever on the Drayton actuator head. It seems to be locked in place and I'm not sure how to move it without breaking it? I guess it's meant to be the manual override for filling? There's nothing in the instructions about what it does or how to move it. Sorry, I must sound a bit stupid. Maybe I should get a Myson, as the valve for the HW Santon tank is Myson and its manual lever is just spring loaded.

 

[ShaunCorbs]

Sorry, just had a thought. There is a small black lever on the Drayton actuator head. It seems to be locked in place and I'm not sure how to move it without breaking it? I guess it's meant to be the manual override for filling? There's nothing in the instructions about what it does or how to move it. Sorry, I must sound a bit stupid. Maybe I should get a Myson, as the valve for the HW Santon tank is Myson and its manual lever is just spring loaded.

If it's has a and b on a label above it, leave that one

There's one other end of the wire, you will see a hole in the centre put a small screwdriver in there and pull away from the body, should pop out easy and move