3 Port Valve - Replace the whole thing or just the head? Videos included!

[Plumb Line]

Hi plumbers and DIYers

I made a post about my 3-port valve a couple of weeks ago, but have finally been able to take a look and thought best to start a new one than tag on. Hope that's ok.

Recap: We've had a problem whereby our boiler will only heat the radiators, even when set to hot water only. Pretty certain the problem is with the three port valve.

With the electricity off, I've removed the head and taken a video to show what happens internally when I move the lever. As you'll see, it slips and clunks. Does that mean that the gears are knackered or is it something else completely? Is it fixable or time for a replacement? Or is it normal? Must say the vids I saw had smooth looking mechanisms...

If it is time to replace the head, should I just do that or do the whole unit? The spindle moves quite freely by hand, as per the third video. It only moves from say 12 to 1 one o clock, but I think that's the normal range isn't it? Is there any other way of telling what condition the T pipe piece is in?

Money is really tight, and if just the head needs replacing I'd be confident doing that myself plus the part would be a bit cheaper.

But in a few weeks we are having plumbing work done in the house which will involve a drain down. So if it is a much better idea to change the whole thing then that would be the time to do it, and I'd bite the bullet on the extra £££.

Hopefully the videos can help shed some light:

3 Port Valve – Google Drive

drive.google.com

Much appreciate any replies 🙂

Cheers

PS - Hollywood here I come!

 

[ShaunCorbs]

Yea sounds like the gears have a few teeth missing as the valve is moveable by hand you can chance just changing the head but buy the complete unit then if the body become stiff you can just get it swapped over

 

[Plumb Line]

Thanks for the advice

Interestingly, I have asked on other forums too. And I've also had a plumber visit since originally posting. There's a real mixture of replies, with some agreeing with you (which includes the plumber), and others adamant that the head is fine and just the valve needs replacing.

I guess that's the internet for ya!

 

[SJB060685]

Thanks for the advice

Interestingly, I have asked on other forums too. And I've also had a plumber visit since originally posting. There's a real mixture of replies, with some agreeing with you (which includes the plumber), and others adamant that the head is fine and just the valve needs replacing.

I guess that's the internet for ya!

IF the valve is free moving with the head off and yes they only move a little then the valve is ok. As you stated in your post and as Shaun and I stated above it sounds/looks like the gears have failed and when you bare in mind when the valve isn't energised and you're relying on the springs and gears to return to HW then I'm pretty confident it's the head. I might be wrong, there are never certainties in life but I would start with the head and it's a 5 minute job for someone who knows what they're doing.
I appreciate you're looking for correct and accurate advice but I wouldn't listen to everything every person on every forum says. There's a lot of idiots out there and fortunately this forum has evicted most up until now.