On 25/05/2014 15:16, Rick Hughes wrote:
On 25/05/2014 11:47, wrote:
Hello

I wonder if anyone can answer a plumbing question. I just changed the
potable water expansion tank for my unvented water system. All seems
to be working fine, but I am wondering if I have a missed a step.

I have a zilmet 24l tank pre-charged to 50 psi sitting at the highest
point in the system. Obviously the tank was full of air when I first
connect it up and I am wondering if I need to bleed the air from the
water side of the membrane to fill it up with water? There seems to be
no way to do it, and no suggestion it should be done, so I will
presumably just contract legionaire's shortly?

Any comments appreciated!

Thanks
Darren

I have 4 Zilmet expansion systems on my install.

The Zilmet 24Litre on Boiler feed loop has just failed (water coming
out of air charge valve) ... so have to obtain replacement next week and
fit.

According to my install instructions - these units are charged with air
when 'not connected' to a pressurised water system ... you would (or at
least should) drain water if you want to check the air pre-charge.

In my case you then fill the pipework and charge up the system to 1 bar
static charge.


forgot to add if this is a closed loop ...which is sounds like, then
there will be an airvent on it somewhere (top of your tank ?) may be an
autovent type.
Or a bleed screw to let air out.

It won't be on the expansion vessel.

--
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