Expansion vessel which one to buy?

[Frizz]

Hi I'm looking at fitting a external expansion vessel to my baxi 105e instant
Just after advice on which are best to buy.
12 litres. Would I need to fit another pressure valve or is the one on the boiler still ok.
Is it best to fit on the flow or return fron the boiler.
The boilers in the loft so plenty of room to fit it.
Many thanks Frizz

 

[Agile]

Best fitted on the return which is cooler.

The preheat will contunue to function if required and even has a larger preheat volume available.

Best to have at least 2m of 22mm pipe to it.

It also needs to be protected against freezing.

Tony



Edited to add that the preheat will still be available if required.

 

[Biggles..]

Best to have at least 2m of 22mm pipe to it.

Tony

Could you please explain where that figure comes from.

Lee

 

[Agile]

Thats my suggestion.

How long would you make it?

He also asked which one to get. They are mostly made by just a few makers and with no obvious advantages, so any one will do.

 

[dcawkwell]

Best fitted on the return. Thats all you need to do apart from disabling the preheat.

Best to have at least 2m of 22mm pipe to it.

It also needs to be protected against freezing.

Tony

What has the preheat got to do with it?

 

[Biggles..]

BEcause the instant uses the vessel for the preheat.
It's suggested by many that If you fit an external you lose the instant function,but think one of the baxi lads once said that isn't the case.

 

[Frizz]

http://www.hot-water-cylinders.com/Robokit-EXTRA-expansion-Vessels-12-Litre_p_4553.html

would this be ok?
do i need all the bits and bobs(technical term) or just the expansion vessel on its own and use the filling loop and prv on the boiler?

or would this vessel only do?
p://www.toolstation.com/shop/Heating/Tanks+Vessels/Expansion+Vessel+12+Litre/d230/sd3234/p70204

 

[Agile]

BEcause the instant uses the vessel for the preheat.

It's suggested by many that If you fit an external you lose the instant function,but think one of the baxi lads once said that isn't the case.

Actually thats totally correct. In fact you get more preheat storage because there is no air in the EXV.

I momentarily forgot that point. I will delete my previous suggestion to turn off the preheat ( if you can afford to run it and the noise does not bother you. )

Tony

 

[namsag]

Go plumbcentre fixed price 12 litre expansion vessel wall bracket and 3/4 to 22mm fitting to go on top 30 quid inc vat

 

[Agile]

"to go on top"

That raises an interesting discussion as to which way up they should go!

 

[Frizz]

Go plumbcentre fixed price 12 litre expansion vessel wall bracket and 3/4 to 22mm fitting to go on top 30 quid inc vat

Has it got to be 22mm pipe? Or would/could you reduce down to 15mm?

 

[Frizz]

"to go on top"

That raises an interesting discussion as to which way up they should go!

Which way up should it go? Some of the brackets I've seen will only top mount with the pipe on top.

 

[mickyg]

Go plumbcentre fixed price 12 litre expansion vessel wall bracket and 3/4 to 22mm fitting to go on top 30 quid inc vat

Has it got to be 22mm pipe? Or would/could you reduce down to 15mm?

no it doesnt matter on the size so much, well at least you'd think that looking at the way combis are designed i dunno why agile thinks you need 2m of pipe. hopefully he'll educate us all on why

 

[monoxide62]

2m of pipe? always thought this to be the wet side.

 

[Agile]

I thought you would all know what I am thinking of?

Think solar!

2m of 22 mm for this is probably overkill, 1m should be OK. But if using 15mm then I would put about 2m.

Tony