Unvented Cylinder Tee Off

[ColinM]

Just a quickie, should i tee off for an exp vessel before a balanced tee off or after? Or does it not really matter?

 

[ShaunCorbs]

why do you ask ?

need a pic as it depends where the balanced it teed into

 

[ColinM]

On the existing installation its after the balance take off

 

[ColinM]

 

[ColinM]

Gonna install a new UVCylinder

 

[snowhead]

Gonna install a new UVCylinder

A second one or a replacement?

 

[ColinM]

Replacement

 

[Riley]

G3?

 

[ColinM]

I'll take a look but i doubt it covers that

 

[ShaunCorbs]

Are you g3 registered he means ?

 

[ColinM]

Yes

 

[ColinM]

Its gonna be my first install and its gonna be assessed by the competent persons scheme so I wanna make sure its done flawless

 

[ShaunCorbs]

Well the new cylinder will come with a combo valve / inlet manifold etc if there’s a port for the expansion vessel there it’s fine to use it don’t use the balanced cold off the for the ev as there’s check valves etc

Or tee in after inlet manifold is fine either

 

[ColinM]

Im asking because as u seem in the pic the Exp Vessel is teed from the combi valve itself. However, as far ive seen i dont think the new heatrae sadia valves have a exp vessel port so if thats the case the tee would occur further down

 

[ColinM]

So tee in after combi valve for ex vessel then down stream tee off for balanced or straight off the valve if it has a balanced port?

 

[ShaunCorbs]

Correct

 

[ColinM]

Cheers

 

[Scott_D]

The balanced cold would be the wrong side of a check valve and so not take up any expansion

 

[ColinM]

So the balanced cold must come of the combi valve? And exp vess tee off down stream of the valve? Same as what i said earlier

 

[townfanjon]

Read the MI’s

 

[chris watkins]

Or go back over the training info you were given with your G3 course.
There must be a cheak valve in place to stop hot cat2 from going back into the balanced cold so putting an expansion vessel inbetween the two would isolate it from the cylinder.

 

[ColinM]

Nooo, yr mis understanding my point. The original question was does it matter which side of the balanced cold the tee off for the exp vessel goes givrn the balanced cold is teed off after the combi valve

 

[ColinM]

And PS the balanced cold is teed offf after the valve

 

[townfanjon]

I can appreciate why you asking the question , but its the most basic question with an unvented.
Look at the combi valve , it does everything.
Balance and ex vessel , you are making this very complicated .

 

[ColinM]

In.the earlier thread u see i mentioned that the new heatrae sadia valves dont have a exp vess port

 

[townfanjon]

In.the earlier thread u see i mentioned that the new heatrae sadia valves dont have a exp vess port

The MI’s will tell you

 

[chris watkins]

In.the earlier thread u see i mentioned that the new heatrae sadia valves dont have a exp vess port

So the tee for any expansion vessel connection must go in between the cold feed connection to the cylinder and the expansion safety valve fitting as that contains the check valve, required by the Water Regs.
The balanced cold would need to tee off in between the expansion safety valve fitting and the pressure reducing valve, all as per manufacturers instructions.
or the expansion vessel tee could go on the hot outlet but they don't last long if rubber is heated and if you run any length of pipe to stop this you run the risk of problems with stagnation.

 

[ColinM]

Ok.... so by default, the combi valves must incorporate a take off port for the balanced cold?

 

[Scott_D]

Ok.. so by default, the combi valves must incorporate a take off port for the balanced cold?

Not if the check valve is separate

 

[ColinM]

Ok I understand, thankyou. Your explanation has made the penny drop. Thanks again