Honeywell 3 port diverter snag?

[doitmyself]

When my boiler fires up it heats the water and radiators regardless of what is selected. I'm guessing that this means the valve is not moving from the de-energised position?

Its a Honeywell V4073A. The manual/auto lever moves freely both ways and will not latch in the man position.

1. If the rads an HW are being heated the valve has moved to mid-position. The de-energised position is HW only.
2. If the lever moves freely, the valve is stuck open. There should be resistance when the lever is move from Auto to Man, and return to Auto when released.

Try this:

Turn the power off at the main switch. (Setting HW and CH to Off at the programmer is not enough)
Check if the lever is stiff or loose.
If loose the valve is stuck open; if stiff, the valve has returned to rest position.
If there is a small bump on the top of the valve, you can remove the actuator (control box). Remove the metal cover then undo two screws (one each side) and remove motor etc. This will expose the valve spindle.
The spindle should be easy to turn by hand - but only about 20 degrees. If it's hard to turn you could try applying some silicon lubricant where the shaft goes though the base plate. (WD40 is not recommended as it can rot the seal.)

If this doesn't work, you will have to replace the whole valve.

 

[John Armstrong]

Great. l’ll have a crack at it tomorrow....

 

[garygvl]

No it doesn't.
Basic but safe. I'd be happy to replace a powerhead or a synchronous motor
No I don’t...

Here’s something that may be relevant:
All the pipes are now cool but the unit itself is still quite hot!

on a 3 port mid position valve if the last demand was heating the motor stays powered up until a call for hot water only pulls it back to its rest position so the valve will stay hot with pipes around it staying cold

 

[John Armstrong]

on a 3 port mid position valve if the last demand was heating the motor stays powered up until a call for hot water only pulls it back to its rest position so the valve will stay hot with pipes around it staying cold

Cheers Gary

 

[garygvl]

Oh I love a “ max” quote when you have never seen the job lol

had a job years ago where cust said heating coming on when only hot water selected. turn up ask cust where is the airing cupboard need to check 3 port valve. no sight of valve in airing cupboard so looked elsewhere couldnt find it anywhere. eventually out of desperation looked behind the cylinder and found it had been installed first and then cylinder fitted in front of it. full drain down of system and removal of cylinder to change valve. did change pipework so it wasnt behind cylinder but cost a few quid

 

[townfanjon]

had a job years ago where cust said heating coming on when only hot water selected. turn up ask cust where is the airing cupboard need to check 3 port valve. no sight of valve in airing cupboard so looked elsewhere couldnt find it anywhere. eventually out of desperation looked behind the cylinder and found it had been installed first and then cylinder fitted in front of it. full drain down of system and removal of cylinder to change valve. did change pipework so it wasnt behind cylinder but cost a few quid

My point exactly lol

 

[Harvest Fields]

had a job years ago where cust said heating coming on when only hot water selected. turn up ask cust where is the airing cupboard need to check 3 port valve. no sight of valve in airing cupboard so looked elsewhere couldnt find it anywhere. eventually out of desperation looked behind the cylinder and found it had been installed first and then cylinder fitted in front of it. full drain down of system and removal of cylinder to change valve. did change pipework so it wasnt behind cylinder but cost a few quid

2 hours max

 

[garygvl]

2 hours max

ok if valve accessable and open vented system with good lock up on tank 1hr tops. if pressurised and good access to valve happy days

 

[John Armstrong]

Try this:

Turn the power off at the main switch. (Setting HW and CH to Off at the programmer is not enough)
Check if the lever is stiff or loose.
If loose the valve is stuck open; if stiff, the valve has returned to rest position.
If there is a small bump on the top of the valve, you can remove the actuator (control box). Remove the metal cover then undo two screws (one each side) and remove motor etc. This will expose the valve spindle.
The spindle should be easy to turn by hand - but only about 20 degrees. If it's hard to turn you could try applying some silicon lubricant where the shaft goes though the base plate. (WD40 is not recommended as it can rot the seal.)

If this doesn't work, you will have to replace the whole valve.

OK Finally got everyone out of the house!

Powerhead off.
Valve tricky to turn by hand, silicon applied. Turns easily with pliers, about 20 degrees total movement.

For info: motor was still hot and auto/man lever seems to work as advertised now its off.

Back together again now. Just running the sytem to see if anything has changed.

 

[doitmyself]

The spindle should turn easily using the fingers.

If it sticks again you can get a replacement ball valve and O-ring. It's part no "272752A/U CARD". Some draining down may be required, but it saves having to remove the valve body.

 

[John Armstrong]

The spindle should turn easily using the fingers.

If it sticks again you can get a replacement ball valve and O-ring. It's part no "272752A/U CARD". Some draining down may be required, but it saves having to remove the valve body.

Cheers doitmself
At the mo it looks like nothing has changed.
Is it worth ackling the valve a few times to work the lube in?

 

[doitmyself]

What do you mean by "nothing has changed"?
a) valve still sticking, or
b) the original problem is still there.

It might be worth the effort. The problem is the o-ring which creates the seal round the spindle dries out and shrinks, making it harder for the spindle to rotate. The spindle may move up and down a little, which will help the lubricant to work its way in.

 

[John Armstrong]

What do you mean by "nothing has changed"?
a) valve still sticking, or
b) the original problem is still there.

Sorry, I meant
B) the original problem is still there. But Im guessing that means that
A) valve sticking
IS the cause?

 

[Harvest Fields]

May be stating something that you have checked already. But have you checked the timer out?

 

[John Armstrong]

May be stating something that you have checked already. But have you checked the timer out?

Timer? Sorry youve lost me.....

 

[Harvest Fields]

If you have changed the head on the valve and you still have the same issue and the centre spindle on the body is moving freely, then it might not be the valve.

 

[John Armstrong]

If you have changed the head on the valve ........

I havent changed the head, just removed it for fault finding.

 

[Harvest Fields]

I’m now confused. Apolgies in advance if I sound rude. So you have changed nothing and still have them same issue?

 

[Johnm]

The motor is designed to be stalled on CH only and will be quite hot if powered up. In mid-position it runs via a rectifier to hold it static so it uses half power & runs cooler. Definitely worth checking whether the motor moves first.

 

[Johnm]

Timer? Sorry youve lost me...

Presumably you have a timer or programmer that turns both the HW & CH on & off. This would be in series with their respective thermostats. All need to function to make the valve work as intended.

 

[SJB060685]

As Johnm says. These valves hold last port of call. If CH was last the valve remains energised and in CH position, this leads to valve remaining hot and motor burning out over time. If HW is last port of call the valve would of spring returned to that port and hold. When HW and CH are called for together then the valve is held in mid position via a diode creating pulses of dc current to motor, this is enough to overcome spring tension but not enough to motor to CH only. With what you’ve said I’d be suspicious of the head. Probably best just to replace whole valve like others have said.

 

[John Armstrong]

I’m now confused. Apolgies in advance if I sound rude. So you have changed nothing and still have them same issue?

No need for apologies!
As you can see I am not a plumber, so I am checking first for easy stuff that I can do myself before calling in the experts:
I have removed the powerhead. It seems mechanically sound.
The synchronous motor is hot when powered so I am guessing that replacing that won’t help.
The spindle on the valve moves easily with pliers. I’ve lubed it. Does it move freely enough for the motor to turn it? Not sure.
Put it back together and nothing has changed.
Is the valve too stiff or is it something else?
Answers on a postcard please!

 

[John Armstrong]

With what you’ve said I’d be suspicious of the head. Probably best just to replace whole valve like others have said.

OK. Thanks, I see your logic.

 

[Harvest Fields]

OK. Thanks, I see your logic.

Hasn’t this been mentioned already?

 

[John Armstrong]

Hasn’t this been mentioned already?

Yes. So was this:

If it sticks again you can get a replacement ball valve and O-ring. It's part no "272752A/U CARD". Some draining down may be required, but it saves having to remove the valve body.