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

[Johntheo5]

Hi all,
Ok, heres a system sketch from what I can see.
Hope it makes sense, Im no Picasso!
The boiler, magnaclean and PV are all in the loft, approx 3M above ground level.
The pump is a Grundfoss UPS2. Ive checked the compression fittings, all are good and tight. Pump flow is pointing the correct way.
The cold water feed tank was literally 20cm higher than the boiler when removed and pressurising the system.

View attachment 350456

The EV should be teed in before the pump which should give a higher system pressure and less chance of air ingress.
Also, the boiler MIs show a AAV, I would definity check or gegt it checked out in case its pulling air in there, the cap on these is generally closed after initial fill, it maybe accessible from the boiler top but unlikely.

 

[kugaman1]

Yeah, the expansion vessel is on the return. Not a lot I can do about that, thats where the plumber fitted it.

My overall thought is that the expansion vessel isn't an issue at all, after all I had it fitted to try and address this air ingress problem, so the problem was there before the vessel was fitted.

Not sure if the boiler has an auto vent and if theres an issue with it….certainly something to consider if no other solutions work!

 

[Johntheo5]

In most cases changing from a OV system to sealed does cure the problem.

Its a very simple task to change the EV to the pump inlet, where it should be located, the pump may be cavitating due to the EVs present teeing in to the boiler return.

Have a look right on top of the boiler, it showes a manual vent thats accessible on the system version at leasr, probably the same on the heat only boiler, see how much air is released from there.

 

[fixitflav]

Yeah, the expansion vessel is on the return. Not a lot I can do about that, thats where the plumber fitted it.

My overall thought is that the expansion vessel isn't an issue at all, after all I had it fitted to try and address this air ingress problem, so the problem was there before the vessel was fitted.

Not sure if the boiler has an auto vent and if theres an issue with it….certainly something to consider if no other solutions work!

Is there inhibitor in the system?

 

[kugaman1]

In most cases changing from a OV system to sealed does cure the problem.

Its a very simple task to change the EV to the pump inlet, where it should be located, the pump may be cavitating due to the EVs present teeing in to the boiler return.

Have a look right on top of the boiler, it showes a manual vent thats accessible on the system version at leasr, probably the same on the heat only boiler, see how much air is released from there.

Ok, will have a look.
Pumps definitely not cavitating, runs smooth and super quiet.

Ive ordered a couple of Aladdin autovents, cant do any harm can they….

Yes fixitflav, there is inhibitor in the system - i add a bit extra via the mag clean every time I have to top up the system following another venting session!

 

[Johntheo5]

Was the system chemically cleaned before the new boiler installation?, I`ve come across some horror stories of probems if these systems arn't properly flushed out before adding inhibitor.

 

[Mottie]

I so wish I could upload a video…I could let everyone see how much air is ejected when I bleed the system!

Streamable.com. Upload your vid to that and post the link on here.

 

[kugaman1]

Was the system chemically cleaned before the new boiler installation?, I`ve come across some horror stories of probems if these systems arn't properly flushed out before adding inhibitor.

No, but the system gets a clean/drain refill with fresh inhibitor every couple of years. In fact the installer of the boiler commented on how clean the water through the radiators was….

Ive found the installer guide for the boiler (greenstar ri 24) and cant see any mention whatsoever of an auto vent in the boiler….not mentioned on any of the install/commissioning/servicing pages…

 

[kugaman1]

Streamable.com. Upload your vid to that and post the link on here.

Ok, will do.
We are on holiday for a week from tomorrow, so I will sort it when I get back.

 

[Johntheo5]

No, but the system gets a clean/drain refill with fresh inhibitor every couple of years. In fact the installer of the boiler commented on how clean the water through the radiators was….

Ive found the installer guide for the boiler (greenstar ri 24) and cant see any mention whatsoever of an auto vent in the boiler….not mentioned on any of the install/commissioning/servicing pages…

No manual vent on the boiler top, accessible without removing the boiler casing?

 

[kugaman1]

No manual vent on the boiler top, accessible without removing the boiler casing?

Nothing visible on top and no mention at all in installer handbook….

 

[Johntheo5]

Can you post a link to that handbook.

 

[kugaman1]

Can you post a link to that handbook.

https://www.mrcentralheating.co.uk/media/catalog/product/installation-manual-for-12-24-ri-regular-erp_3.pdf

 

[Johntheo5]

Thanks Andy,

It does show a manual vent, Item 26 in the main components page but don't think you can access it without removing the rear panel so probably need to be gas registered to do that, wonder if your installer vented the heat exchanger using it as its the highest point in the system, anyhow see you get on with the Alladins.

 

[SpecialK]

Get the pipework tested to 10 bar. This will put your mind at ease that there are no leaks that would allow air in, it wont rule out the boiler.

In order for air to enter a sealed system it must be higher than the water pressure. How is air going to be injected in to the pipework?

Do you have any dead leg pipework or radiators that could be full of air? Ones that no water or air come out of when you bleed the system?