Shouldn't there be an...

[dilalio]

... air vent on the water side of an EV?

This occurs to me every time I'm working on one!

What says the rest of you's?

 

[Dan Robinson]

Nah

 

[dilalio]

Why

Edit: or why not? Seems fairly logical to me but, that might not say a lot...

 

[Dan Robinson]

What good would it do?

 

[Razor900]

The air that's trapped there will eventually dissipate into solution but in the meantime it just kind of makes the expansion vessel perform like a bigger one

 

[dilalio]

Well, my thinking is that it would act as a pocket of air that would encourage corrosion and never dissipate but if you say it will then I am wrong

 

[picasso]

I have seen that somewhere, sure it was an old boiler I took down but cant remember the make.

 

[Steelmasons]

The system water is constantly expanding and contracting into the EV bladder so an air vent would be pointless , if the vessel has been pre-charged correctly the pipework to the vessel will be constantly flooded with water upto the bladder.

 

[Steelmasons]

...anyway..I thought you were a heating engineer?????..do you possess a G3 ticket???
...I'm on a wind up dilalio although I would like an honest answer...

 

[Aquaheat]

I've found that they perform better if you remove the factory precharge of air and replace it with a premix of nitrogen and oxygen at roughly a 4:1 ratio. Obviously it cost the customer a little more but the long term benefits easily out weigh the initial cost.

Jon

 

[Dan Robinson]

premix of nitrogen and oxygen at roughly a 4:1 ratio.

 

[Steelmasons]

I've found that they perform better if you remove the factory precharge of air and replace it with a premix of nitrogen and oxygen at roughly a 4:1 ratio. Obviously it cost the customer a little more but the long term benefits easily out weigh the initial cost.

Jon

3.7:1 to be exact..

 

[Dan Robinson]

a 4:1 ratio

Fecking amatuer.

 

[Aquaheat]

3.7:1 to be exact..

My Regin pump has the in built N/O2 4 stage blending valve fitted so I leave the mixture control to that. It's calibrated every 3 months to achieve the optimum blend. I had to have a special canister attachment made to allow an extra bottle to be fitted. This introduces a dab of Ar and CO. I believe that this helps the N and O2 to achieve a stability that will allow for a better and more progressive rate of expansion as opposed to just air.

Not cheap though, the pump cost £168 and the calibrations and refills are £84 a pop hence why I charge a premium to swap the gases over. Customer is always impressed with the overall long term benefits it provides though.

I also exchange the Shrader valve insert to a specialised one for this mixture. They look the same but can withstand the new mixture better and would only need replacing once every two years instead of yearly.

Jon

 

[Phill Peck]

There are a few boilers out there with aavs on the EV can't think of one of the top of my head though.

Main combi he??