Exchanging 3 way valve, valve?

Hi,

A while back I asked about a motorised 3 way ch/hw valve that was giving the symptoms of allowing ch when hw was called for.

I got the chance to test the valve from cold yesterday.

Removed the valve head Rotated the valve to the hw position Powered up the system.

I kept my hands on the pipe work either side of the valve (as far as I could from the valve itself) and felt both sides heating up nearly equally? ;-(

So, this suggests to me that the valve itself is faulty (damaged ball etc) and whilst I'm more than happy to change the entire valve body (it's on fairly short pipes that may need some 'persuading') it looks like the valve itself is secured to the face of the valve body with 4 screws and sealed with an 'O' ring and so, might be swappable with another / new / good unit?

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I have seen just the bodies available new for around 20 quid so this would just cost the elderly lady that plus fresh inhibitor etc?

Worth a go ... or what are the chances the valve seats are worn etc?

Cheers, T i m

Reply to
T i m
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I would think it more likely that they will need cleaning up. The ball is often some sort of "rubber" and the seats can end up with a rough ring of rubber stuck to them as the ball deteriorates. The ball also moves only a few millimetres and arrives at the seat flat on, so there is little chance of seat wear.

SteveW

Reply to
Steve Walker
<snip>

Just or as well as replacing the ball?

Understood. I think the ball must have deteriorated fairly badly (on one side possibly) because the rate at which both outlets heated with the valve in the CH position was pretty similar?

Understood.

So, are you confirming that the idea of just swapping the valve mech should be worth a shot?

Cheers, T i m

Reply to
T i m

Make sure one is in stock then drain and investigate.

Reply to
DerbyBorn

I think you can only buy the body on it's own [1] off eBay so I might do that for her *anyway* and then I have the option of just the plate / ball valve or change the whole body.

Would it be ok to fill / flush with fresh water to check for leaks / functionality before committing to the inhibitor?

Cheers, T i m

[1] I think you can only officially buy the head, or head+body (complete solution), not the valve body on it's own.
Reply to
T i m

I've just been dealing with the same mymptom caused by the ball-stem seizing, a common mode of failure. You can replace any faulty part of it, including the ball-plate. The base (Below the ball plate) is not subject to wear. Beware of used parts. I saw base sections new on ebay for about £22. Obviously you need to know what's faulty first.-

NT

Reply to
tabbypurr
<snip>

Not the case in this case I'm afraid, the shaft is 'finger turnable' and even when turned firmly to HW only, you still get CH.

Whist I couldn't imagine the valves being assembled with 'matched' actuator arms / ball-valves, I thought I'd ask here first.

Understood. I was concerned if it could simply be a piece of limescale that could be impinging across the face of the CH outlet.

I would only go new on this sort of thing.

Well, other than it's difficult to go much further without examining the insides of the valve?

*If* the valve actuator arm, ball and mounting plate should be interchangeable between all such valves (Make / model etc) then I'll first get one, then drain the system and examine the valve by removing the side plate. If it's that (damaged ball and I don't know what else it could be), then I could first swap the backplate and if there is some compatibility issue, put the complete new valve body on (that I can test for leaks before fitting etc).

Cheers, T i m

Reply to
T i m

Well if you're getting outputs from both ports, the motor is moving to halfway and stalling as it should. Which leads me to question if the valve is actually the problem. Have you monitord its electrical lines?

easy enough to scrape it, but assuming it's a vaguely modern primary the water seldom changes, so no limescale opportunity.

very unlikely

It could be an electrical issue. They also suffer from swollen balls sometimes. I can only hope that's not your problem.

NT

Reply to
tabbypurr

No need mate, the valve was turned into the HW only position manually and heat was still felt in the CH pipes.

Ok.

Really, between the *same* make and model?

See above.

;-)

Well, I'm pretty sure it is a mechanical issue with the CH outlet not being closed off properly.

Cheers, T i m

Reply to
T i m

ah, communication issues. Aren't they fun

TBH it sounds like a swollen ball is a prime candidate. I feel sorry for you. Have you run it with the head off, moving the shaft to HW only by hand? If it still heats the CH then, you must have a swelling problem. I'm told you can buy replacement balls.

NT

Reply to
tabbypurr
<snip>

"I got the chance to test the valve from cold yesterday.

Removed the valve head Rotated the valve to the hw position Powered up the system."

Or some mechanical valve related problem, likely to do with the ball.

Oooh, a link would be nice. ;-)

Cheers, T i m

Reply to
T i m

if the shaft moves, the ball is the only real candidate.

I've never had that problem myself. I just got the whole lower end assembly with shaft & ball. Removal turrned out to be painless. I couldn't get the old O ring out so used a bit of linseed putty to reseal. £22.99 on ebay.

NT

Reply to
tabbypurr
<snip>

So I hoped it could be, if it was acknowledged that all the valves / bodies (from the same make / model / version) were interchangeable etc.

Ok, I was thinking silicone sealant.

Check.

Cheers, T i m

Reply to
T i m

I just got the exact same model number.

NT

Reply to
tabbypurr

The replacement I've got doesn't have a model number on 'it' as such?

I'll offer it up and compare it physically before draining down the system. ;-)

Cheers, T i m

Reply to
T i m

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