Removing Expansion Vessel.

[chatrail]

Hi All,

I have a toilet I am going to replace that is fed water from a tank in the loft (via a pump). The toilet has a wash feature and was fitted for the previous (disabled) owner. It has been nothing but trouble so its time for it to go, so to the issue...

There is a dedicated 50 Gal tank in the loft that feeds a pump (via a flow switch) and the pump feeds the loo on the floor below. The feed pipe out of the pump to the loo has an Expansion vessel fitted (I don't know why as it all cold water). I have no issue with the removal of the tank, pump and related bits except the Expansion Vessel (I have never worked with them), do I need to "discharge" it before removal of the pipe work or does it 3.5 bar of charge not leave the device ?????

I did say I have never used them, although I DO understand what they are for (in hot water systems) and I have carried out most of the re-pumb on the rest of the house (water only), had a CORGI man in to do the heating.

 

[Bahco]

It will only be charged with air so no problem to remove. It probably is charged to 1 bar or less, all the pressure being on the air side of the diaphram.
Drain down first then remove all.
I take it you will be modifying pipework to run off direct mains

 

[chatrail]

Thanks for the help. Do you have links to how these vessel work. I'm still at a loss to understand what is preventing that 3.5 bar of air causing a "kick back" on the wet side ??

As for the feed to the new loo. The feed to the tank goes via the bathroom (and feeds a second loft tank) I was goting tee off in the bathroom to provide a mains feed.

 

[kevplumb]

so let the air out if your nervous

valve on top

 

[chatrail]

I have now found a page on the Internet that has made the whole thing clear.

The vessel uses a rubber balloon like "bag" attached to the water connection flange. Therefore when there is no water in the bag (as would be the case once I have drained it) the 3.5 bar is applying equal force on all parts of the (now flat) bag, so is always held within the vessel - cute.

Thanks again for your help guys.

-Paul.