no mid position valve wiring on the s plan wiring diagrams .

[caoimho]

hi
i have just wired up an s plan honeywell system according to the wiring diagrams..seemed easy enough only it has wiring for a 2 port hw valve and a 2 port ch valve.only thing is i have a mid position valve on the ch. does this require a movement of wiring? perhaps bringing the white wire into play...very grateful for any help thanks

 

[ArtfulBodger]

yes!!!! http://content.honeywell.com/uk/homes/systems.htm

 

[kevplumb]

why a mid pos on the ch

 

[ArtfulBodger]

why a mid pos on the ch

Personally I like the bringing the white wire into play quote, sort of dots the i's and crosses the t's doesn't it?

 

[Agile]

Let me try to be a little more helpful although "Brianmad" does not agree.

A Honeywell "Y" plan is for a single three port mid position valve.

A Honeywell "S" plan is for two two-port valves.

You have to realise the letters "S" and "Y" are different.

You can use a three port valve instead of a two port valve if you know how.

You can use two two-port valves in place of a three port mid position valve if you know how.

You can use a three port valve without mid position if the HW is to be satisfied first before any heating is to be provided.

All these simple logic statements should be sufficent to help you work out what you have done wrong and it sounds like muddling up "S" and "Y" plans. You will need to be able to manipulate logic statements. Some older people remember how a ZX81 was programmed!

Tony Glazier

MOD

"S" & "Y" corrected

 

[doitall]

Em

is that the wrong way round Tony

 

[Agile]

Yes, sorry it was John, but it is corrected now!

Tony

 

[ChrisR]

Sure you can use a mid pos as a two port - but it matters rather a lot which connection isn't used, and what you do with it!!

 

[doitall]

Sure you can use a mid pos as a two port - but it matters rather a lot which connection isn't used, and what you do with it!!

Where would port B go Chris as it would leak every time it powered down

 

[ChrisR]

Not if you cap it off

 

[caoimho]

yes i understand that the 3 port should be on a y plan but it is on my s plan so i need to know how to wire it up correctly .it worked fine before the wiring was dismantled for building work.just need to know the wiring sequence but no diagrams seem available for this

 

[doitall]

you wouldn't happen to have an unvented cylinder by any chance

 

[ChrisR]

If you use the white wire as a live signal to make the valve open (like the brown on the 2 port) the valve will go to mid position. You may as well connect the gey one to it as well, so the valve will go right over.

Blue is neutral. Orange goes live once the valve is open, so connect that to whichever is coming from the other valve* as a Switched Live for the boiler.

* conventionally Grey on a 2 port goes to permanent live, so Orange becomes live when the switch oin the valve closes, but some people connect them tother way round.

I should wait half a day before connecting as I indicate - by then someone will have looked it up and proved me wrong, or not.

 

[doitall]

I was looking at why he would have a flow share valve Chris and still waiting for an answer.

Lets assume the flow share is the standard Y plan and the 2 port was an unvented cylinder valve which should be wire through the thermal cut-out.

 

[ChrisR]

Yes I wos aware of your line of consternation. COuld be somebody used the 2 port for the UV, thought it looked complicated so used the 3port for the CH alone. You question does need answering, whatever!