[beenthere]

Looks like the vent is piped up to a bypass. Won't get rid of air too well that way. What temp is the boiler high limit set to, and what PSIG is it running at.

Are the rads old seam rads, that were converted over to hot water.

 

[beenthere]

Are you pumping away from the expansion tank/air vent?

Looks like toward them, and the circ is mounted in a position(motor up) that the system should be at 20PSIG.

 

[beenthere]

Yes, its tied into the supply side and all the water is not forced through the vent. There are 2 tees in the main supply that build this vent/expansion manifold. I was wondering how good of a job this configuration could do. Would adding another vent or re-doing this one help me?

All the water is to go through the vent. And of course it should be much bigger.