I have a hot water heating system with the accordian style baseboard heaters and every time the heat comes on there is quite the party in the pipes. I shut off the main switch for an hour and then I started at the top and bled the radiators and it helped quite a bit, but I just don’t know how long I am supposed to bleed them for. How much water do I let out squirt out ? Thanks in advance.
Once water comes out, if there is no more air coming out as bubbles, it is time to stop bleeding for the while. Air will collect again for a while, then you can do it again and get some more bubbles. If there is no automatic vent valve on an air scoop in the system, you will have to do this manually over a few days to get the air out.