Gate Valve to balance HW primary flow?

[slippyr4]

Hi chaps,

I'm in the latter stages of installing my DIY "Y plan" CH/HW system (although i'm not doing the new boiler myself (i don't have a death wish)).

I've been installing an entirely conventional design. But yesterday I was in Wickes (I apologise for that) and looked through their How-to leaflet on installing CH systems.

Their diagram included a gate valve on the return from the HW heat exchanger, apparently to "balance" the flow when the mid-position valve is in the mid position. I've never come across this. Is it necessary? A good idea? A waste of a gate valve?

I'm worried i've missed a bit out!

thanks

slip

 

[kevplumb]

the idea is to slow the flow through the h/w coil which is 22mm as opposed to starving the rads

 

[chrishutt]

Not essential, but without balancing the bulk of the hot water flow will go to the hot water side when valve is in mid position. This is not a real problem if cylinder is high recovery and can heat up quickly, so minimising time in mid position. But a gate valve costs next to nothing (£2?) and is easy to fit, so why not give yourself the option of making adjustments if necessary?

 

[slippyr4]

Ok, i will fit one. Should it be before or after the cylinder? or doesn't it matter? after would be easier, with my pipe layout.

 

[chrishutt]

After is fine. If before, make sure you don't obstruct vent pipe route from boiler to expansion tank (if open system).

 

[slippyr4]

no, its a closed system (will be getting a system boiler). that's why i want to fit it after- the HW side of the mid pos valve goes to a automatic vent then to the cylinder, and not really room for a gate valve.

after it is. thanks all.

 

[kevplumb]

closed systemi
ie pressurised fit it on the flow then

 

[chrishutt]

pressurised fit it on the flow then

Why

 

[kevplumb]

and not really room for a gate valve.

 

[chrishutt]

the HW side of the mid pos valve goes to a automatic vent then to the cylinder, and not really room for a gate valve.

But that's the flow pipe, isn't it? He wants to fit on return because there isn't room on flow.

 

[kevplumb]

so put it on the return
whats the odds
its only slowing the flow down

 

[slippyr4]

Thanks chaps. all done now:-

[/img]

 

[chrishutt]

It's a brave man who posts a pic of his handiwork on this site...

 

[slippyr4]

It's a brave man who posts a pic of his handiwork on this site...

I know. Suprised i haven't got flamed yet. it's been online for a couple of hours already.

Whilst it may not be perfect, it's a lot better than many examples i've seen that some "plumbers" have installed.

 

[chrishutt]

It's been posted 13 hours now and not a titter Maybe it's a perfect installation? OK, it obviously needs insulation on the pipework, but since it's "work-in-progress" that doesn't count. Looks like you got away with it...