Fitting auto air vent

[DuncanM]

Been advised to fit an AAV on return of a sealed system to try and keep air out of the HEX as it keeps error coding about circulation. Power flushed the system already, this is the next step.

Anyway, usually fit AAV on positive side of pump so how far away from pump to make sure AAV does not suck air in?

 

[Gasmk1]

why not go with an air separator bit more expensive but also good for the system

 

[DuncanM]

why not go with an air separator bit more expensive but also good for the system

Are they not for open vent? Or would I put an AAV on top? Also can it go on return before pump? Been advised by technical to do this. It goes against what my understanding of how an aav works. Thanks.

 

[Gasmk1]

air sepaar

Are they not for open vent? Or would I put an AAV on top? Also can it go on return before pump? Been advised by technical to do this. It goes against what my understanding of how an aav works. Thanks.

No they are for either Vaillant recommend fitting air separator and magnetic filter air separator removes micro bubbles
spirovent-microbubble-deaerators-brass

 

[SJB060685]

AAV or air separators are best positioned in the circuit with higher water temperatures and lower pressure. The solubility of gases decreases as the temperature is higher with lower pressure, therefore ideally installed on flow after boiler.

 

[DuncanM]

AAV or air separators are best positioned in the circuit with higher water temperatures and lower pressure. The solubility of gases decreases as the temperature is higher with lower pressure, therefore ideally installed on flow after boiler.

So you concur that fitting it on the return could actually suck air in as it is before the pump. What about gasmk1 idea is it also on the flow? Thanks.

 

[SJB060685]

The way I see it with these float operated AAV etc that if mounted on the return before the pump as you're describing they could like you say draw air in if default or under lower pressure, negating the whole idea in the first place.
When mounted on the flow under higher temperatures these gases don't dissolve so much and are free to escape into the atmosphere.