Unvented wiring .

[townfanjon]

Strange request for Easter Sunday lol , its just in my head .
have any of you fine chaps got a wiring diagram for a y-plan with a new 2 port wired in for an upcoming unvented installation.
I usually change them to an s-plan but the boiler is miles away from the cylinder and would cause a load of work getting perm lives to the 2 ports .
Cheers in advance

 

[EvilDrPorkChop]

Creates more hassle than it's worth IMO. Have you checked the wiring, you usually have enough wires to do it anyway, especially if theres already a pump overrun.

 

[Aire]

Can you add a 2 port to a y plan? With the 3 port keeping one zone permanently open, what happens when the 2 port calls for heat? You'll get unwanted heating of a zone.

 

[EvilDrPorkChop]

Can you add a 2 port to a y plan? With the 3 port keeping one zone permanently open, what happens when the 2 port calls for heat? You'll get unwanted heating of a zone.

Yes you can. It's on the HW side, so you can leave your 3 port in situ and have the 2 port for thermal cut out for the Unvented after the 3 port valve. It's doable but for everyone that i've come across it's not worth the hassle and easier just sticking two 2 port valves in.

 

[Aire]

Yes you can. It's on the HW side, so you can leave your 3 port in situ and have the 2 port for thermal cut out for the Unvented after the 3 port valve. It's doable but for everyone that i've come across it's not worth the hassle and easier just sticking two 2 port valves in.

Ok, I get what your saying, but if the 2 port acts only as a thermal cut out, what happens when the cylinder stat on the first cylinder is satisfied but the thermostat on the second isn't? You could end up with unbalanced temperatures.

 

[townfanjon]

Creates more hassle than it's worth IMO. Have you checked the wiring, you usually have enough wires to do it anyway, especially if theres already a pump overrun.

Ancient boiler pal , so no spare wires but just realised there must be a hw off wire , but really need 2

 

[townfanjon]

Ok, I get what your saying, but if the 2 port acts only as a thermal cut out, what happens when the cylinder stat on the first cylinder is satisfied but the thermostat on the second isn't? You could end up with unbalanced temperatures.

I have never done it but a 2 port should be fitted on to a y plan unvented installation, yes a right pita

 

[EvilDrPorkChop]

Ancient boiler pal , so no spare wires but just realised there must be a hw off wire , but really need 2

If you've got a HW off wire then you're sorted. Change that for a perm live, you'll already have Neutral and Earth there, along with HW on and CH on.

It's when you haven't got a HW off wire that's the issue (So when they have to have HW and CH at the same time)

 

[Aire]

I have never done it but a 2 port should be fitted on to a y plan unvented installation, yes a right pita

So your not having 2 cylinders? Why do you have to a 2 port on a yplan when feeding an unvented?

 

[townfanjon]

If you've got a HW off wire then you're sorted. Change that for a perm live, you'll already have Neutral and Earth there, along with HW on and CH on.

It's when you haven't got a HW off wire that's the issue (So when they have to have HW and CH at the same time)

I have not looked , I just thought of it as I was typing

 

[townfanjon]

So your not having 2 cylinders? Why do you have to a 2 port on a yplan when feeding an unvented?

In case it goes *** up , spring return valve closes supply to cylinder

 

[EvilDrPorkChop]

So your not having 2 cylinders? Why do you have to a 2 port on a yplan when feeding an unvented?

Part of the G3 regulations. Must have a thermal cut out, as a 3 port valve is always open in some form that doesn't meet the requirement.

See so many Unvented cylinders on 3 port valves, it's worrying! Had one where the High limit stat kept cutting out, so cylinder must have been about 85/90oc!

 

[townfanjon]

If you've got a HW off wire then you're sorted. Change that for a perm live, you'll already have Neutral and Earth there, along with HW on and CH on.

It's when you haven't got a HW off wire that's the issue (So when they have to have HW and CH at the same time)

Wheres yer GS badge ??? Admin still in the boozer

 

[EvilDrPorkChop]

Wheres yer GS badge ??? Admin still in the boozer

Must be! 😀

 

[Aire]

Part of the G3 regulations. Must have a thermal cut out, as a 3 port valve is always open in some form that doesn't meet the requirement.

See so many Unvented cylinders on 3 port valves, it's worrying! Had one where the High limit stat kept cutting out, so cylinder must have been about 85/90oc!

Good to know, I suppose if I had my g3 I would have known that 🙄

 

[EvilDrPorkChop]

Anyway to answer the original question, just looking at a diagram you'd still need a perm live anyway for a 3 port plus 2 port.

 

[townfanjon]

If you've got a HW off wire then you're sorted. Change that for a perm live, you'll already have Neutral and Earth there, along with HW on and CH on.

It's when you haven't got a HW off wire that's the issue (So when they have to have HW and CH at the same time)

I am no sparks , is it acceptable to use the one perm live and split to supply both 2 ports ? Assuming there is one lol

 

[EvilDrPorkChop]

Good to know, I suppose if I had my g3 I would have known that 🙄

Many of the 3 ports that i've seen have been left in/fitted that had their G3 qualification.

It's daft really, the Manufactures instructions clearly state that a 2 port is needed, along with them sending one with the cylinder. If it comes with the cylinder then you'd be thinking I have to fit this thing!

 

[Riley]

Wheres yer GS badge ??? Admin still in the boozer

Ha ha

 

[townfanjon]

Anyway to answer the original question, just looking at a diagram you'd still need a perm live anyway for a 3 port plus 2 port.

I cant find one anywhere lol