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

[DIYNotIan]

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:

https://drive.google.com/drive/folders/1uDVtF8t8_L7f5pekzgGtGM89wzy4q7nN?usp=sharing

Much appreciate any replies

Cheers

PS - Hollywood here I come!

 

[kidgreen61]

First of all try the spindle on the valve to see if it moves easily (only a few degrees either way) with your fingers.
If it does, just replace head, if it is seized, replace the whole thing

 

[ianmcd]

valve looks fine so just change the actuator head, the gearing mechanism is slipping, buy a genuine honeywell one and not the cheap imitation ones

 

[DP]

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...

Honeywell actuator will do that when not attached to the valve. I would put the actuator back onto the valve and then attempt what you are doing

 

[DIYNotIan]

Many thanks the replies

Interestingly, I have asked about this on other forums too. And I've also had a plumber visit since originally posting. There's a real mixture of replies, with some saying just the head needs changing (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!

Honeywell actuator will do that when not attached to the valve. I would put the actuator back onto the valve and then attempt what you are doing

Fair play, I'll give that a go. Once reconnected, when I try again is it ok to do so with the power off or does it need to be on?

Cheers

 

[DP]

Fair play, I'll give that a go. Once reconnected, when I try again is it ok to do so with the power off or does it need to be on?

Cheers

With power off actuator attached to the valve. With cover still off try different permutations and see what the valve is doing. When valve mid position look at the lever that is close to the micro switches.
With just heating on, micro switches operate.
With just hot water calling the valve restores under spring action.

if it does not, either the valve spindle is causing this to happen else spurious induced voltages. Put power off, if valve now restores to home position, then it is spurious voltages.