Boiler above Hot Cylinder

[ChrisNason]

I need to move (and replace) the Boiler from the (downstairs) kitchen to the (upstairs) airing cupboard. The cupboard is 500mm wide but 1200mm deep. Ceiling is normal 8ft. It seems sensible to have the hot water cylinder on the floor and the boiler above it.
All the diagrams I've seen show the boiler below the cylinder with the pump mounted at about half the cylinder height.
Is it possible to do what I want and if so what height should the pump be at.
By the way, the F&R tank (and Cold water tank) will stay in the attic.

 

[spacethegas]

as long as clearances, fluing position etc are ok it shouldn't be a problem.

the pump can go anywhere as long as its piped correctly.

 

[ChrisNason]

I've looked at this document from Vaillant and on page 15 it shows the "recommended relationship of pump cold feed" etc.
Obviously these must be set up right and my alignment would not go against this but the pump is shown above the boiler.
Am I reading too much into this?

http://www.vaillant.co.uk/stepone2/...plus_open_vent_installation_and_servicing.pdf

 

[gas4you]

Yes!

The 400 series has the F & R off the top of the boiler therefore why they show it like this.

 

[ChrisNason]

So...
Does that mean it's OK to have the pump below the boiler?
At present the Cold Feed and Expansion are set up to join just under the pump at about the correct 150mm apart. However, my expansion is nothing like the "450mm Minimum" above the surface of the F&R tank (which is being replaced anyway). Perhaps this is why I'm 'pumping over' when the radiators switch off?
I also note that Vaillant don't quote a minimum height for the F&R above the boiler. Is there any guidance on this? I could work down from the roof and mount the F&R within 450mm of the attic high point so that it sits about 900mm above the airing cupboard ceiling. The Boiler then sits high in the cupboard (after allowing for flue exit)

 

[spacethegas]

i refer you to my previous answer.

+ it might be worth fitting an air separator & a surge arrester on the open vent.

 

[ChrisNason]

So pump OK.
I was expecting that an Air Separator was needed but hadn't come across the surge arrestor. More Googling.
I also saw a set up with an automatic air vent on the highest point. I don't have this. A well known (and probably the largest) plumbing company in London also stated that I don't need an automatic bypass valve. They said stick with the gate valve. Do you agree?

 

[spacethegas]

if a bypass is required so is a bypass valve.

http://www.heatingcontrols.org.uk/Site/downloads/TACMAGuide.pdf

 

[ChrisNason]

Sorry. I didn't make myself clear. The old boiler (and presumably the new) needs a bypass valve. The question is whether it should stay as a standard gate valve (cracked open) or an automatic valve.

 

[spacethegas]

the answer is in the pdf.

 

[ChrisNason]

well it was a very small note!

 

[spacethegas]

not difficult to read if magnified.

+ it tells you any other system improvements that are preferred & those that are mandatory.

 

[ChrisNason]

and thankyou for your help

 

[ChrisNason]

When the boiler is above the cylinder where should the Air Separator be sited? Does it go at Boiler height?

 

[spacethegas]

wherever convenient.