Pressure vessel change

[wozza56]

Right after advice from a few people it was thought that i had to repressure my combi but after reading the FAQ it seems that i need a new vessel as there is water coming out of the air valve
I have now got a new vessel and was wondering if there is a right way and a wrong way to change it ? im assuming i turn it all off shut all the valves and then drain off a few buckets and then swap them over .Am i right or is there an easier way ?

Thanks in advance

 

[Axel]

You have to de-pressurise the system, and catch any water that comes out of the pipe for the old vessel after that. Make sure the new vessel is secured to wall with appropriate bracket. New vessels usually have air charge, but you might want to check the air charge pressure is correct for your system BEFORE you re-pressurise the water side, as you can't measure it or adjust the air charge while the water side is pressurised.

 

[wozza56]

Thanks Axel but the reason i am changing it is because there is no pressure ,so do i just drain the water off ?

 

[Burnerman]

Hi Woz
Axel means that you depressurise the water side of your system before undoing the pipe to your EV.
Do this via a radiator bleed until there's no pressure registering on the gauge.
The EV will have a few litres of water in it for you to catch once you disconnect it!
John

 

[wozza56]

Thanks John ,the boiler pressure drops to zero anyway when the heating goes off so i assume i just drain off a few buckets of water

 

[Burnerman]

Yep thats about it really - if there's no pressure in the systems then its more difficult to get water out of the rad valve bleeds.
Undo the EV hose, and see if you can collect it from there, if there's no other convenient point.
John

 

[Axel]

If the water is not coming out, then it's ok ! There is probably a 15mm compression fitting on the half inch bsb threaded fitting that goes onto the vessel.

Don't forget the PTFE!

 

[wozza56]

Thanks guys i will have a go tomorrow