Honeywell 3 port diverter snag?

[John Armstrong]

G'Day fellers. Appreciate your help please:

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. A test I found which involves turning the heating (only) on, holding the lever on manual then turning water on to check the valve motors across, did nothing.

A quick look under the cover shows the springs are OK and no sign of burning. The system was drained and refilled 6 years ago.

Over to you!

 

[Last Plumber]

G'Day fellers. Appreciate your help please:

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. A test I found which involves turning the heating (only) on, holding the lever on manual then turning water on to check the valve motors did nothing.

A quick look under the cover shows the springs are OK and no sign of burning. The system was drained and refilled 6 years ago.

Over to you!

When you turn the power off at the Heating isolation, does it close?

How competent at Electrical work are you?
Do you have a multimeter and know how to use it?

 

[John Armstrong]

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!

 

[Rob Foster]

I would wait until the cold weather has really gone ...then have a play , sounds like a new head. Rob Foster aka centralheatking

 

[Harvest Fields]

I would wait until the cold weather has really gone ...then have a play , sounds like a new head. Rob Foster aka centralheatking

2 hour job max if it is the whole valve Rob.

 

[John Armstrong]

2 hour job max if it is the whole valve Rob.

Sure, but the question is : Do I need to replace the whole valve with associated system drain?

 

[Riley]

Associated system drain? Are you asking if you can get away with just changing the head?? I would do the lot.

 

[Harvest Fields]

Sure, but the question is : Do I need to replace the whole valve with associated system drain?

Depends on the age of the valve?

 

[Old Account]

Sure, but the question is : Do I need to replace the whole valve with associated system drain?

Sometimes worth changing in full and perhaps replace like for like

 

[Last Plumber]

I would power off, test that it's off (pull a fuse and use a voltage tester). Remove the motor and check it over. They are normally fairly stiff to turn the cog beneath but will move. if it's jammed, replace it. They can be bought from DIY stores and are fairly cheap.
It could well be the head or valve but it is worth checking the condition of the motor first.

 

[John Armstrong]

Remove the motor and check it over. They are normally fairly stiff to turn the cog beneath but will move. if it's jammed, replace it.

Ok, so remove the motor and see if the spindle can rotate:

If it doesnt, buy a new one. If it does, assume a problem with the electrical supply?

Anyone worried by the housing being hot when the pipes are cold? Would this indicate a motor trying and failing to move the valve? Wouldnt this just burn out the motor?

 

[Last Plumber]

Ok, so remove the motor and see if the spindle can rotate:

If it doesnt, buy a new one. If it does, assume a problem with the electrical supply?

Anyone worried by the housing being hot when the pipes are cold? Would this indicate a motor trying and failing to move the valve? Wouldnt this just burn out the motor?

It will do that if the motor is stuck. Eventually it would burn out.

 

[Riley]

Hence I’d change the whole thing

 

[John Armstrong]

Hence I’d change the whole thing

But you’re a plumber! 😉

 

[townfanjon]

2 hour job max if it is the whole valve Rob.

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

 

[Riley]

But you’re a plumber! 😉

You’ve said the motors hot I’d say it’s struggling to turn it hence I’d change it. I don’t say it for fun

 

[Old Account]

But you’re a plumber! 😉

Perhaps you should get a decent plumber in to do the works for you.,

 

[fixitflav]

Wouldnt this just burn out the motor?

I don't think so. The earlier either/or valve (W-plan) definitely wouldn't, the motor stalled in the CH position, and it could stay that way all day. It dissipates about 5 watt in that condition.
I'm not 100% about the mid-position valve, but I think it probably does the same when CH only is calling. Wiring diagrams for both attached, if you want to try to work it out.

 

[John Armstrong]

Perhaps you should get a decent plumber in to do the works for you.,

That is the plan IF the valve is faulty.
Thats why I’m trying to diagnose first.
As mentioned, if its just the motor or powerhead, i could do it myself.

 

[Harvest Fields]

That is the plan IF the valve is faulty.
Thats why I’m trying to diagnose first.
As mentioned, if its just the motor or powerhead, i could do it myself.

If you are getting a pro in. There is no need to diagnose. He will do his own fault finding even if you tell him it is the valve.

 

[Last Plumber]

It might be best to get someone to look at it. A competent Heating Engineer will be able to diagnose the fault in a short time. It may be a wiring issue.

 

[Harvest Fields]

It might be best to get someone to look at it. A competent Heating Engineer will be able to diagnose the fault in a short time. It may be a wiring issue.

Let’s hope note. As we all know that we love sorting out other people’s wiring.😛😛😛😛

 

[Last Plumber]

Let’s hope note. As we all know that we love sorting out other people’s wiring.😛😛😛😛

Nothing worse is there.
I always completely disconnect everything from every Heating component and wiring box and start again. It's easier and quicker than trying to trace someone else's mess. Plus, once it's done I know its right.

 

[Harvest Fields]

Nothing worse is there.
I always completely disconnect everything from every Heating component and wiring box and start again. It's easier and quicker than trying to trace someone else's mess. Plus, once it's done I know its right.

The first time I had a wiring fault I spent 3 hours trying to trace it and got nowhere. Then decided to pull it all out and rewire. Complete and working in 30 minutes. 🙄🙄

 

[Last Plumber]

The first time I had a wiring fault I spent 3 hours trying to trace it and got nowhere. Then decided to pull it all out and rewire. Complete and working in 30 minutes. 🙄🙄

Always the best way. If there's any doubt, rip em out.

 

[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.

 

[SJB060685]

If the valve is sticking causing your problem of both CH and HW on at same time then there’s only so much you can do to prolong its life. Like I mentioned above as well with this particular design of valve the synchronous motor is likely to burn out over time leading to nuisance replacements. You’re best bet is to save time and money and replace the whole valve, be it you or an engineer. I personally don’t like these valves because of the problems we’ve mentioned, I always preferred an S plan but again they fail over time as well

 

[Johnm]

this particular design of valve the synchronous motor is likely to burn out over time leading to nuisance replacements.

The motor is designed to be permanently stalled. The motor is fed through resistors & a diode and my last valve failed because one of them had failed. I didn't realise that was the problem until after I had changed it to an S plan. Now have changed it back to Y on boiler mfrs recommendation to avoid need for bypass. If the spindle turns easily you don't need to replace the entire valve, just the motor or head. There should never be a long term demand for heat or HW.

 

[SJB060685]

What I meant John is if CH was last port of call then the motor will burn out over time. I know how the valve is held in mid position if you read one of my above comments. Am I wrong?

 

[Johnm]

When the CH is satisfied the valve should move back to midpos and then be held there by the rectified pulses. However, if there is a demand for HW it will unpower and spring would take it to HW.

 

[SJB060685]

This suggests to me that it’s last port of call is held and it doesn’t return to mid position. If I’m wrong then I’ve been wrong for years lol

 

[doitmyself]

These diagrams show what happens in the different positions. When CH only has been satisfied, the valve still stays in the CH only position due to voltage from the HW stat SAT or programmer HW OFF.

 

[SJB060685]

Like I said above @doitmyself

 

[John Armstrong]

Though this might be useful for diagnostics: I removed the powerhead then turned the supply back on (yes I put the cover back on the first!) Then turned on the CH/HW.

I can move the valve manually and I can hear it kicking over, so I’m guessing the valve is fine.

The powerhead isn’t behaving as it should, though I did wonder if that was because it isn’t physically attached to the valve?

My money is on a duff powerhead. What do you guys think?

 

[Harvest Fields]

I only ever change the heads first unless I know the body is passing, but then again I also have bodies on the van.

 

[John Armstrong]

I changed the powerhead.....
and it seems to have done the job. 😀

 

[Harvest Fields]

I changed the powerhead...
and it seems to have done the job. 😀

Awesome news

 

[Riley]

If you have bought the whole valve I would keep the brass bit as the other one definitely sounded like it wasn’t moving that freely

 

[John Armstrong]

If you have bought the whole valve I would keep the brass bit as the other one definitely sounded like it wasn’t moving that freely

Sure
And in the meantime it’s going to be perfect for lobbing at that cat that keeps coming to take a s**t on my lawn. 🙄

 

[John Armstrong]

Nearly forgot:
Thanks all for your time and expertise.
Cheers