Radiators won't bleed!

[Keys]

Hi,

I had my boiler serviced this summer and all good.

I'm now starting to use the heating and have noticed that they are not cold all the way up. So I have tried to bleed them but no air or water comes out, on all apart from one radiator.

I then tried turning the radiators all off, then one by one bleeding them, and this worked,

However once I bleed 3 of 7 radiators, I checked the first and it's filled with air again, and so have the others.

It seems air is constantly in the system.

My boiler is about 12 years old, and its one of the ones with a tank for cold water, not a combi boiler. I can't find a pressure gauge like in my old flat where I could top up the water.

Any ideas? Appreciate the help!

 

[HERTS P&D]

Check in the loft to see if there is water in the expansion tank, push the float valve to see if water comes out or you could have a blocked cold feed.

Andy

 

[Keys]

Hi,

I forgot to mention I live in a flat. I have a water tank above the bathroom but I had a look and couldn't see any float (although quite difficult to see).

I read somewhere it may be the pump... Should I do something with that?

 

[CBF]

you need to check you have water in the tank, the ballvalve can stick in the closed postion like herts said push the end of the ballvalve down & make sure the tank is filling up

 

[oilhead]

It may not be a combi boiler, but could still be a system boiler which is sealed. Are you sure the tank above the bathroom is not a header for the hot water cylinder? I think you probably have a filling loop somewhere; can you check with someone in the other flats?

 

[Keys]

Hi,

Thanks for the replies.

I believe the water tank in the bathroom feeds cold water to the cistern and cold water taps... It might actually not be related to the heating system actually...

Weird thin is the heating had been left off today, and I've manage to bleed all radiators. A lot of air but eventually all bled.

Think it's something to do with air being drawn in when it's on?

 

[HERTS P&D]

You only bleed with the system turned off.

It also proves you have an expansion tank somewhere.

Andy

 

[Keys]

Ahh brilliant cheers, thanks for the help!