Hi everyone! My kid's bedrooms are making a pipe banging racket and it's getting worse. Suspect air in my pipes but don't know how to bleed my system. An hvac guy was here once when my wife was home and said that this isn't something that I can do myself. I can't believe that and was hoping to have the help of some folks here to do just that.
We have a gas fired furnace, with a couple of zones. Only my kids zone in particular, is noisy. It's served by a B&G series 100 booster pump/circulator that I circled in red below. There are shut off valves above and below the pump and a faucet right above it, which I assume is for bleeding the system. You'll see that there are also a series of shut off valves along the top of the photos.
What I don't know is:
1. what are the valves along the top for? if they're not the return line, then my system would seem very odd as it would seem the circulator is on the return side when I would assume it would be at the side of the source.
2. if i'm to bleed the system, which of the three inline flow valves do I have to close, there is one above the red pump, one below it, and another along the top (question 1 above, i'll have to guess which one serves my kids bedroom)
3. when I am bleeding just the circled one (2nd floor kids room), do I have to close off all the valves for all the other zones?
4. i assume that when I am bleeding the system, i would turn on the tap after lifting up lever on the regulator stepping down the municipal water flow to force the water through the system. Not sure if I lift that regulator control slightly or all the way?
Thank you all so much. My wife and children thank you!!!
Some more photos for reference: