I had a new boiler installed. After the installation, I realized that the new pipes were routed such that the feed was going into the old return lines. I have an 80 year old house with 3" main feed line and 1.5" return. Now the output from the boiler goes into the prior return lines.

I find that I keep getting air in multiple radiaters. I have to bleed some of them every two weeks for 15 minutes before the air is all out. Some just put out a little air and loose pressure. Do I have a clog secondary to displaced deposits related to the water flowing in the opposite direction?

I find that many of the radiaters elevate to the same tempurature regardless if the valve to the radiater is on or off. I suppose that now the valve is on the outlet side of the radiaters instead of the inlet side since the water is routed backwards. Could this be the cause for the valves seemingly not working? Could the radiaters be getting hot water passively through diffusion?
Thanks...