air lock

[gaspastemania]

Need idea of removing airlocks on large gravity circuit, Has 1 f & e tank which feeds 3 zones of heating which has a boiler for each zone.Approx 20 radiators over the 3 zones with only a couple in each zone warming up . The circuit itself is alarge circuit and is old . Hestitant to back fill because of age of the circuit and was not able to use bungs either due to cust wanting full drain down .
The AAV'S by the boilers are chocked up but dont want to go down the route yet of removing them if i can avoid it so any suggestions of getting the air out through vents would be appreciated .

 

[WaterTight]

I'm inexperienced and shouldn't really be offering someone like you advice and I'm sure by idea is moronic...but could you back fill it using some sort of pressure reducing valve turned down as low as you can to back fill with as little pressure as possible...?

 

[ecowarm]

Is it air or could it be sludged up?

 

[SafeGasInstall]

you know very well that options you have a limited to mains push in ,if you try the standard close the ones that work and
have pumps on 3 , what I did on one job was had all air vents on rads open down stairs and start filling and had the pump going like 1-2min after and soon as I had a full rad i did turn them valves off and moved to next one ! it was a fully pump ch and gravity water on a back boiler and pump wast boxed in I could not even get to it to (on the side of a unit with i think 4 book shelf's full of books )

 

[SafeGasInstall]

i think it could be what ecoworm mention above !

 

[gaspastemania]

Really trying to avoid any back fill scenario in all honesty but as a last resort then may have to .

 

[SafeGasInstall]

one thing mate ,did it work before hand ?

 

[Phil]

20 rads? 3 boilers, where are you working Buckingham palace. :dead:

I've always found the best way is to remove each cold rad at a time and put the old wet vac on the rad valves, soon pulls out the air.

 

[gaspastemania]

Sludge is a possibility as air vents are leaking and looks like they are sludged due to water the weeps on them look like thick brown gunk , however on drain down water was standard grey and not overly gloopy. When i filled back up had two guys doing the venting whilst i was up by tank ,i can hear the air clanging around system but it isnt finding a spot to ping out the vent .

 

[Phil]

Actually thinking about it, is this microbore?