primatic cylinder to indirect

[redred]

Hello - some advice please...
Have a failing (leaking) primatic cylinder which i would like to change to an indirect so i can fernox the heating side. There is a back boiler, and the pump is under the floorboards next to it.
my main question is: where do I make the connections from the F& E (which i need to put in) cistern to the flow and return? Can they be where the flow and return go into the cylinder, and if so specifically which (feed/ vent) to which (flow/ return)? ...I'm hoping for a 'yes'!
Cylinder is in a cupboard on the landing, not much room to play with...
Thank you in anticipation

 

[twgas]

cold feed, 15mm, to the return.
open vent, 22mm, to highest point of the flow, must not rise from tee toward the cylinder and rise to at least 450mm above f&e tank water level

 

[redred]

"...must not rise from tee toward the cylinder..."

sorry, not exactly sure what routing you're suggesting...

thank you for your speedy reply!

 

[Biguns]

Not quite sure of the question.But there are loads of sites like this.
http://www.google.co.uk/images?hl=e...tle&resnum=4&ved=0CEMQsAQwAw&biw=1152&bih=709

 

[redred]

What i meant was, I'm not sure what twgas meant when he said the pipe "must not rise from the tee to the cylinder"... what is the orientation of the tee and which direction does it go to get up to the F&E cistern?

 

[twgas]

what I meant was, the flow connection on your new cylinder must NOT be any higher than the tee. Basically the flow comes up from boiler, there's a tee on top of it, one branch goes up, in 22mm pipe, that's the vent. the other branch goes, in 28mm, to the cylinder, this is the pipe that must not have a rise in it. I'll try a diagram,

 

[looneyfitter]

28mm?>

 

[twgas]

looney, do you have a problem with 28mm

 

[redred]

sorry to sound so dumb... do you mean that the tee should be level with the cylinder connection - presumably so any air goes up the vent?
thanks,

 

[looneyfitter]

looney, do you have a problem with 28mm

no just that a standard 3-4 bed would generally be in 22 so whay say 28 and confuse him?>

 

[seco services]

no just that a standard 3-4 bed would generally be in 22 so whay say 28 and confuse him?>

i would say the system is gravity hw pumped heating

 

[looneyfitter]

no just that a standard 3-4 bed would generally be in 22 so whay say 28 and confuse him?>

i would say the system is gravity hw pumped heating

I agree

 

[twgas]

sorry to sound so dumb... do you mean that the tee should be level with the cylinder connection - presumably so any air goes up the vent?
thanks,

basically, yes. although it wouldn't hurt if the pipe sloped down toward the cylinder.

no just that a standard 3-4 bed would generally be in 22 so whay say 28 and confuse him?>

I would use 28mm on gravity hot water, irrespective of size of house.

 

[seco services]

I would use 28mm on gravity hot water, irrespective of size of house.

totally agree.

 

[looneyfitter]

sorry people i was thinking of the hws piping and not the primaries for some reason.

To OP would you not consider having the system altered to a y or s plan? more economical , contollable etc