Y Plan / Mid Position Valve - Odd Boiler Behaviour

[Steve3948]

Yeah, I have and fully understand them 100%, so are you getting me mixed up the OP Mr Tesla.

 

[Steve3948]

Yeah, I have and fully understand them 100%, so are you getting me mixed up with the OP Mr Tesla.

 

[Nicky Tesla]

ye probably O)

 

[Steve3948]

ye probably O)

That's Ok then

 

[Nicky Tesla]

Indeed as it is just a handful of series or parallel switches to operate a load. Which should be no more complex to fault find than two or three way light switching, to an electrically competent person.

Doc H..

Not quite, you need to know whats going on at the valve itself with the micro-switches and resistors. This info is not given out in the box with the valve. Read in detail from the info link i posted earlier.

 

[steptoe]

its still only switches though Nicky,

yes, you have a point about actually understanding how and when they operate,

surely any 'competent' spark should understand this,?

this is the difference between an installer and an electrician steps up IMHO

simply installing hundreds of these does not make you competent at heating controls,

it merely makes you competent at joining a few wires.

 

[Steve3948]

its still only switches though Nicky,

yes, you have a point about actually understanding how and when they operate,

surely any 'competent' spark should understand this,?

this is the difference between an installer and an electrician steps up IMHO

simply installing hundreds of these does not make you competent at heating controls,

it merely makes you competent at joining a few wires.

Well from my experience of employing many sub contractors over the years I feel there are a lot out there who run a mile when you mention heating controls or heating control faults.

It's all logical at the end of the day and step by step procedures should lead you to the problem.

 

[Doc Hudson]

Not quite, you need to know whats going on at the valve itself with the micro-switches and resistors. This info is not given out in the box with the valve. Read in detail from the info link i posted earlier.

I am fully aware of the internal workings of the three port valve, and have been for a long time. Ultimately we are still switching a 230v signal from a supply to a load. Within the Y-plan wiring the 'hot water on' 230v goes direct from the cylinder stat and bypasses the valve altogether as the valve will be in either the home unenergised position or the mid-position if 'Heating on', (white), is also at 230v. It is the 'Heating on', (white), signal that has to either fully drive, if 'hot water is off', (Grey), at 230v. Or drive & stall the valve if 'hot water on', When the heating is on but the water is off the orange output has to give the 230v to the boiler via the internals of the valve. Whenever the hot water is on the boiler will get its 230v direct from the cylinder anyway so it is irrelevant what the orange may or may not be outputting as it will be brought up to 230v by the cylinder stat. It is during these conditions that the apparent 80v -120v can appear back fed onto the white. So I stand by my earlier statement it is simply an array of series switches that an electrician should easily be able to fault find and trace where through the circuit. Unfortunately many installers simply follow instructions to connect wires without understanding what they actually do. I would have though the Honeywell course would have covered fault finding, otherwise is seems a bit of a waste of time to attend?

Doc H.

 

[Nicky Tesla]

its still only switches though Nicky,

yes, you have a point about actually understanding how and when they operate,

surely any 'competent' spark should understand this,?

this is the difference between an installer and an electrician steps up IMHO

simply installing hundreds of these does not make you competent at heating controls,

it merely makes you competent at joining a few wires.

No it isnt, the current through the one of the resistors creates a voltage which doesnt quite switch and holds the motor against the strentgh of the spring (i found a much better link once but cannot find it at the momo )

 

[Doc Hudson]

Well from my experience of employing many sub contractors over the years I feel there are a lot out there who run a mile when you mention heating controls or heating control faults.

It's all logical at the end of the day and step by step procedures should lead you to the problem.

Agreed on all points.

Doc H.

 

[Doc Hudson]

No it isnt, the current through the one of the resistors creates a voltage which doesnt quite switch and holds the motor against the strentgh of the spring (i found a much better link once but cannot find it at the momo )

That is purely for the positioning of the valve for water flow though. The electrical 230v to fire the boiler is; For heating a direct contact from the White 'in' to the Orange 'out' {look at the drawing on your link}. Or for water, bypassing the valve altogether, look at Y-plan drawings. A simple switch in & out signal.

Doc H.

 

[Nicky Tesla]

Ah i found it go down to 4.2.4....3 port valves http://www.boilerinf...m#_Toc107895362

it may be a simple switch in the end but if the motor is prevented from turning from some fault in that area then the switch will not switch cos it runs on a cam

Dont just look at the diagram in the link, read the info

 

[Doc Hudson]

Ah i found it go down to 4.2.4....3 port valves http://www.boilerinf...m#_Toc107895362

it may be a simple switch in the end but if the motor is prevented from turning from some fault in that area then the switch will not switch cos it runs on a cam

Dont just look at the diagram in the link, read the info

I do not disagree with you description of the internal movement of the valve body, but any competent person who knows what signal should be where and during what conditions would also soon identify if a valve was not correctly moving into position and thus failing to operate any micro switch. This in principal is no different to the micro switch on the two port valve, if that gets jammed part way though its cycle. In this particular case according to the OP the valve has been replaced three times! which rather implies wiring and a bit of fault signal tracing and diagnosis is needed.

Doc H.

 

[steptoe]

Nicky,I think yourself, Doc, and myself are actually all agreeing on this, [see folks, sometimes miracles do happen! ]just looking at in a slightly different manner,and I think we are all also in agreement that simply knowing how to connect something up doesnt make you competent at actually installing it [have I contradicted myself from earlier?],maybe not, most installers arent competent at anything except installing,

 

[SPECIAL LOCATION]

most installers aren't competent at anything except installing,

Think most has been covered on this thread already........

But a point worth noting for anyone who is considering these short course training program,

Fault diagnosis or comprehensive explanation of why some wiring is done in a particular way...

Is one of the less essential bits needed to get a pass with the C&G's and Part p compliance...

So is not covered in the course...

and as Steps said there are a whole bunch of wannabe sparks who have had limited training on what to do...

But have no idea WHY...

and therefore when something doesn't work they haven't got a clue how to resolve it or even know what they should be looking for!!!

The other classic example of this is the Dual RCD CU installer..

who cannot suss out why an RCD is tripping!

and has no idea how to trace or resolve a shared neutral or crossed over circuits between RCD's

Its no wonder that heating control bamboozles them!

:C

 

[Steve3948]

+1 on that for sure.

 

[ProDave]

+2 to that.

I can never understand why anyone wants to be a sparky if they have no real understanding of electrical circuits and how they work.

For me, I was interested in, and experimenting with electrical circuits (batteries and lamps you will be glad to hear) from about the age of 10. Electrical circuits always seemed so obvious and logical to me so making my career choice obvious.

But plenty of people do it for some reason, without that interest or understanding in the subject.

 

[binky]

had a call out from plumber mate a while ago, run through all the connections couldn't find anyhting wrong - turned out that new fangled 'easy install' Honeywell wiring control box was faulty. So much for progress. Older control systems can be interesting when you don't encounter them very often, and badly installed (about the only time I get a call from said plumber) Completely re-terminated one mess of wires but mixed up permanent live to roomstat with sw live in process. All looked good when I left, and sorted problem after a quick return visit. It's fairly logical stuff at end of day ray

 

[Wayne Thomas]

Hi all

Looked at a basic wiring set-up with programmer (dual channel), mid position valve, cylinder stat (no room stat) and Keston boiler. Heating engineer stumped so I had a look. If CH is selected at programmer the boiler fires as it should; when CH is set to off - the boiler remains on? Measured 89V at switched live. I know Honeywell valves 'leak' a bit of voltage - not normally enough for this to happen. Heating engineer had replaced the valve twice. What's occurring?

Hi

Sorry to bring up a very old post.

Lilman,did you get to the bottom of this because iv got exactly the same problem. 89v once the heating is satisfied through the switch live, is keeping the boiler on. Iv checked the honeywell MI's and they are stating this is whats meant to happen, between 50 and 150v will stay there. 

Short of me stripping out the y plan and sticking in an s plan at cost to me, my sparky and I are lost. 

Everything has been changed,rewired and triple checked. 

Is there a way of stopping that voltage?

 

[Sidewinder]

Is it a real voltage or a phantom voltage?

If it is real there is a real fault, if it is phantom, then you have an installation issue, which is still a real fault, but needs tackling in a different way.