Loft Expansion Tank

[Wendelspanswick]

I'm in the process of fitting a wood burner with back boiler and a vented thermal store in the barn, it will need a 4 gallon expansion tank and my question is will a Polytank from Screwfix suffice or does it need to be GRP type tank to cope with the possible 100°C temperatures.

 

[I'm getting on a bit]

I see to remember a thread about a copper one being needed

 

[Wendelspanswick]

I see to remember a thread about a copper one being needed

I guess a copper float but I've never seen a copper tank and I've been in alot of lofts!

 

[normspanners]

Think he might be referring to a combined hot and header

BUT ... https://www.mcdonald-engineers.com/products/feed-expansion-tanks
but why not just get a used redundant small insulated copper hot water tank and cut a hole in top for the lid ?

 

[Kayos]

I'm sure you can get a polyplumb one rated for solid fuel, plumb center are good but can be spendy

 

[julianf]

Im doing one (kind of) currently.

Ive not looked up the regs, but i was under the impression that it needed to be metal. Loads on ebay for £200 ish. Lots of used tanks on ebay for pocket change though.

 

[julianf]

http://www.ebay.co.uk/itm/STAINLESS...hash=item2ec895775d:m:mQT567ssxsp9BCDW3R2EIWQ


vs

http://www.ebay.co.uk/itm/HOT-WATER...622383?hash=item3d479f39af:g:7voAAOSwAPlZsn6~

(and a bit of time)

 

[addjunkie]

Mine isnt metal but cant remember what its made of other than its a black plastic, and it does get hot..

Mine is an open loop for the back boiler pumped through a heat exchanger, as the thermal store , heating system etc is all sealed. Pump cuts in and out on temprature at the back boiler outlet. When this pump starts, a relay shuts down the oil fired boiler.

 

[magnet]

As far as i am aware it should be metal or grp to prevent heat distortion from boiling water coming up the vent and into the tank.

 

[Olderisbetter]

You can't beat the old rivited galvanized tanks...till they go rusty and leak..