I did see there was a previous post concerning this subject, but am not able to find it so here's a new one. In the basement, we have a separate boiler system from the forced air HVAC that supports the rest of the house. There are 3 separate loops. One in particular sounds as if it has running water rushing through it. My husband found what he believed to be the high-point bleed valves in order to remove air. He held up rubber tubing to catch any excess water in a bucket below. Buckets of water ended up being removed from the system. I could see bubbles rising from the tube in the buckets of water so I do believe air is/was trapped in the system. I believe he said the water regulator was set to allow fresh water into the system at this time. He told me the system reads 12 PSI. To me, the rushing water sounds louder than ever. He disagrees and says it sounds the same (I think it's fair to share his opinion, too). I'd say it went from a trickling sound to a running sound. To me, the pipes also seem hotter. What do you think happened, if anything? Should we do any follow-up work?