Open system sucking in air, closed system still sucking in air! Any help or pointers?

[mcmoby69]

From what I can see the pump looks like it is on the flow from the boiler and the magnaclean is on the return.
I may be wrong. I would therefore also assume that an auto air vent would be installed on the return pipe from the boiler or there is one inside the boiler.
If I'm right, I think when the pump runs pushing water away from the boiler, any air causing the float in the AAV on the return or internally to drop, allows more air to be pulled into the system until the next glug of water forces the float in aav back up again. Then a plug of air comes round again etc etc etc.

I've only skim read this thread so might be a clog out. Move the pump onto the return

 

[Johntheo5]

A link to the boiler in one of the posts above does show a vent but its apparently a manual one.

 

[mcmoby69]

It was only fitted around 6 months ago - my problems exist before and after fitting. The system holds pressure - the only time pressure is lost is when I vent the system - I then have to refill it.

Has the expansion vessel been left at the pressure set in the factory? Usually about 3bar. Needs setting to suit installation. Normally about .75bar.
I would personally drain the system, deflate the ev, refill the system slowly using the bleed on the ev arm as it looks like the highest point. Once all the air is removed. Pressurise the ev to .75 bar drain or refill the system accordingly.

 

[Johntheo5]

Well, I’ve fitted 2 Aladdin auto vents to a couple of radiators….lets see if they help solve the problem!

I know its only 5 days since installng the Aladdins and you are only using the boiler a few times/day for DHW but have you noticed any venting going on, or/and assuming you have the manual vents on the opposite rad ends to the Aladdins, are you getting any air from these vents?.
What is the boiler flow temperature, if the boiler has hot water priority then it may be as high as 80C.

 

[kugaman1]

Not sure John….inbetween nightshifts just now so living life as a zombie….

Will do some checks once Im back in the real world…but certainly haven't heard any venting from the aladdins!