Heating system keeps creating air in the system

Burti16

Hi All

I recently had my 20 years old, inefficient but perfectly fine working boiler replaced and this is the starting point of all issues.

The issue I could not sort out is that radiators are not warm enough due to air in the system. Yesterday I bled the radiators once more and system pressure drop from 1.2 to circa 0.4. So, almost entire system was full of air.

I tried to repressure the system but when I turned on top up valve, no water came. Top up valve was working fine before boiler replacement and all other taps are working fine.

Any idea about the root cause? I try to avoid calling the cowboys who made the installation as this is 3rd issue in 30 days and there are better experts in this forum.

My two cents, top up system not delivering water when the valve is turned on and this is where air coming from. Could this be right assumption? If so, why there is no water in top up system?

Markcheese

There may be 2 seperate valves to turn to top up the system ,( that doesn't explain why the system is full of air ),

DublinDilbert

Heating system won't create air. There is either a leak or the system is venting (assuming a sealed system) when it is warm. You (or someone else) will need to figure out which of the two it is.

John.G

https://www.boards.ie/discussion/2058292019/heating-system-keeps-creating-air-in-the-system

What make/model of new boiler, also old one, if known.

Can you post picture of top up valve and associated pipework, is there a flexible stainless steel hose attached to the top up valve?

Burti16

https://www.boards.ie/discussion/comment/120468625#Comment_120468625

The 1st pic is the boiler piperwork and the second pic is top up pipe that used to work normally before new boiler installation and located in hot press room in 2nd floor.

The boiler is Worcester Bosch Greenstar 30i. I literally watch every YouTube video and read the manual but fill up valves that are mentioned on the videos are not available on my boiler

John.G

OK, Open the Red Gate valve a few turns, the pressure gauge is attached to a PRV (pressure reducing valve), there should be a plastic knob on the bottom of this PRV, open it anti clockwise slowly until fully open if no pressure rise, slacken the lock nut on the adjusting screw on top of the PRV and then slowly turn the adjusting screw clockwise (down) very slowly until the pressure starts rising, stop screwing it down when the pressure reaches 1.5 bar, shut the plastic knob, shut the red gate valve.

You can let the adjusting screw as is, just nip up the lock nut.

Burti16

https://www.boards.ie/discussion/comment/120468750#Comment_120468750

John you literally fixed the issue. When I said this issue to cowboys they said this is auto fill system and they can't do anything.

Amazing! Thanks man. If you're somewhere in Kildare, allow me to a get you beer one day

Escapees

Note that if system is losing pressure so quickly, the expansion vessel may need replacing or there is a leak somewhere. You shouldn't need to top it up very often at all.

Burti16

https://www.boards.ie/discussion/comment/120469019#Comment_120469019

Ok thanks a lot. As far as I remember pressure was very stable until I bleed the radiators

Escapees

Sorry, I'd forgotten that you'd bled the rads. Happy days so!

Markcheese

Are your rads heating evenly ? I'm just wondering how the system could have been balanced properly if there was lots of air in the rads ,,?

Burti16

https://www.boards.ie/discussion/comment/120471471#Comment_120471471

The house is well insulated, heating 24h on and TRVs are installed each radiator. So, the radiators are never too hot . Last Monday I was out for two days and turned off whole system. When I came back and the restarted the system, I found out the attic loft radiator was warm only whereas others burning hot.

It took literally more than 1 minute to empty the the air... I'm not sure how this much air entered the system

10-10-20

That amount of air is not right for any system, obviously. Did the installer carry out a pressure test on the system? If not, it sounds like you might need one and a check-over off a plumber to identify any leaks.

Burti16

https://www.boards.ie/discussion/comment/120471952#Comment_120471952

No, I don't think they did such test.What's pressure test btw? All I remember was, they filled the system and run it for 30 mins