3-way valVe trouble

[JM2]

I'm having some trouble with my 3-way valve, replaced fairly recently by all accounts. I'm sure you'll recognise everything.

I have very restricted space here.
How does the case unit split away from the mechanical valve?
And what position should it be in to best disconnect. Does the power need to be on or off?

I want to see if I can see some misalignment or micro-switch failure.

The valve is sometimes sticking in what I think is the HW position once the HW is satisfied and ignoring the CH call for heat.
Sometime a light tap to the plastic case will with get it moving again, other times it is a pita to coax into movement - the far side of the case feels hot as if one solenoid/relay/resistor/motor has been trying. Attempting to move the small black lever manually seems fruitless.

I can see the middle black lever at the front (pic1) and feel the rounded black piece at the back (pic2) but squeezing these isn't releasing anything for me.

If I can't release it, or can't fix it, what is the best way to leave the heating so at least we don't freeze - can I lock off the unit with the lowest (moving) lever?

 

[HootingOwl]

Push the black plastic button on the side of the plastic head and pull it away from the metal body. It looks like a Drayton valve. Screwfix will sell you a replacement head but sometimes it is cheaper to buy the entire valve and chuck the body into the scrap bin. These are fairly rubbish valves but are half the price of a Honeywell valve.
Fairly irreparable.
Mains voltage inside.

 

[stem]

A 3 port valve normally sits at rest in the hot water only position. When heating is required, the motor winds it to the central position if hot water is also required, or fully across to the heating only position if hot water is not required.

If you are getting hot water only, that suggests to me that the motor or valve may be sticking at rest where it is retained by a spring. If the valve is under some strain because of it pushing against adjacent timber, this may twist the valve head and stop it operating freely.

The odd thing is with your description, that if this is the case, and the valve is sticking at rest, you would normally be able to feel some resistance when the manual lever is moved.

Looking at the photos, I doubt there is sufficient space for you to remove the head whilst the valve is still attached to the pipework.

There are two micro-switches inside the valve. One operates when the valve is in the central position and is responsible for holding the valve there, and the other operates when at the far end of its travel to operate the boiler when central heating only is required.

Make sure the electrical supply is properly isolated. There could be a live supply to parts of the valve even when the hot water and central heating are off at the controls.

 

[JM2]

The timberwork is clear of the plastic case. Whether or not there's enough room to pull the unit off I don't know yet.

It seems stuck fast on the pipework. Depressing the button at the front, the clearest one in that first picture is not releasing anything. Does it need to go beyond flush with the outside of the case? (as if to use an implement to push it in)

The lever does have some resistance and some movement (but this was when it was powered up). The fruitless part was that it didn't trigger the thing into life, I thought it should.

 

[Gasguru]

You're pressing the wrong button....press the one on the side.

 

[JM2]

Yes the one on the side (not the lever at the bottom).

But in pic1 - is the one I've been trying.

 

[Terrywookfit]

Hold the button in and give it a wiggle.
You will need at least an inch clearance from the head to any obstruction.

 

[stem]

The fruitless part was that it didn't trigger the thing into life, I thought it should.

No it won't do that. All that the manual lever does is move the valve to the central position. It's really for allowing the system to be filled initially as all of the ports are open.

The manual lever won't drive the valve fully across to central heating only, which it would need to do to operate the microswitch and start the boiler, because in that position, the hot water port would be closed. [When the hot water is calling for heat, the hot water cylinder thermostat controls the boiler]

 

[BingoBongo]

its hard up against the joist, that head will never come off

 

[JM2]

Okay, small distraction. Back to the task.

Right, yes, that push button. It has released eventually - that was pretty much stuck on. So the plastic case with contents moves away from the valve now but no more than 1/2". I can see the rather narrow valve operating spindle but not enough space to lift off the case completely.

The case isn't touching the timberwork as fitted, but has a too smaller gap to work with.

Okay too on the manual lever - just repositioning the value to mid-setting, it seems to do that fine. But if unattached to the micro switches it isn't going to exercise those.

So just for me to check:
To replace the electrical part of the valve, the whole lot has got to come off again, including drain down.
And the pipework needs to be re-worked to enable this to be changed in the future (what muppet put it there and replaced there too). So that'll be, pump output pipe, it's top valve, the bypass pipe, 3-way (3-port) and HW feed and CH feed pipes.

This is going to be quite a task in this space. Is this all okay with near 90° bends everywhere or should the pump o/p, valve and HW/CH feeds be near straight and installed ?

 

[JohnD]

which way is up? Which pieces are true joists?

I wonder if there is a noggin that could be temporarily removed, or shaved

 

[JM2]

This annotation shows better the orientation.



The hw tank is sitting on H.

The woodwork of A has slight cut out marks. As fitted there is a small finger's width to woodwork B. But it is C that needs cutting back the most.

All that would weaken the framework quite a bit.

I'm wondering if I can live with it for winter and come the warmer weather get the pipework re-jigged to allow the valve to sit so the case sits at about the orange box position. The only thing is the pump feed pipe would need another few RA joints in it. Would this be okay or make it noisy/inefficient ?

 

[JohnD]

you mean it's a platform for the cylinder to sit on, rather than the floor?

 

[JM2]

H - Yes.

This pipework and pump is above the floorboard level.

 

[JohnD]

then I think you could fit some new legs, in a slightly different position, and cut away the obstacle.