Baseboard: No Bleeders/NO Isolation Valve

Roztom1

Greetings: I have a mixed system. Radiators with 2 basboard zones hooked in paralel. The baseboards have no bleeders and other than the purge valve on the boiler, that's it. I have tried purging the air through the whole system but I can't dislodge it from the baseboards. They only get slightly warm while the radiators blast. I do understand the difference in mass between radiators and the basboard convection heat but the baseboards just don't get hot.
How can I get the air out of the baseboards. The way they are setup the pipe for the baseboard runs back over the fins. Looks like they were just spliced in with one side on supply and the other on the return. If putting bleeders in is the solution, how can I know if that will get the air out? Also are their any other solutions without doing heavy plumbing other than the bleeders?

Thanks,

Tom

redline

Is there an elbow on these?

Roztom1

I am not sure what you mean but where the in/out copper comes out of and back thru the floor there are elbows. The pipe comes up runs thru the fins and then reverses back on itself and goes down at the same place in the floor. IT is a loop and is hooked on both sides. One supply and other return. No valves or bleeders. Only one purge valve at boiler for the whole thing. Sorry for repaeating, just want to be sure I am describing it clearly.
I have run a lot of water thru and have put pressure as high as I can so PRV goes off, I think I have all the air out of radiators but basebaords get barely warm while radiators are blast furnaces. IF I put bleeders on, do they go on the return side at the elbow at the highest point? Any other way to do it. This mixed setup has been this way for many years. I find it hard to believe there wasn't a way tog get the air out.

Tnx,

Tom

redline

You should be able to unsolder one of the elbows and then solder on a new bleeder.