Can't seem to get air out of hydronic system!

Users who are viewing this thread


New Member
Reaction score
I've attached a link to a drawing of my system.

I have a banging in my pipes. It started after replacing the circulation pump. I have tried to bled the system. There are no bleed valve on any of the registers. Here's how I did it.

I have two loops, upstairs and downstairs, that do not have done valves. They meet and go into and out of the boiler as one. But, they each have a quarter turn shutoff.

I turned off the thermostat so it wouldn't call for heat.
I let the system circulate until the pipes cold down to not introduce cold water to a hot system.
I then turned off the pump.
I turned the shutoff to the "air tank". The pressure relief tank or whatever it's called.
I shut off both loops quarter turn shutoff.
I opened the spigot on one loop just a little bit.
I turned up the water pressure coming into the house.
I opened it enough to keep the pressure above 20 while flushing.
I let it run until it was good and cold. It just ran on the floor to the floor drain in the garage.
I turned it off and quickly opened the other one.
I repeated the same steps.
When I was done. I set the regulator to 12 psi. It doesn't have the flip handle on the top, just a screw. So I opened the quarter turn shutoffs on the loops, drained the air tank, closed its drain, opened its shutoff (I had shut off earlier) and left it fill back up with water (and whatever air stays in it.
I verified the system was at 12 psi cold, (my max water rise is about 8 to 9 ft) turned on the pump and double checked pressure and turned the system on (called for heat).

I still have banging while it's heating up and what sounds like air when I go to the boiler.

There is a spigot on the side of the boiler. I wasn't sure if there's a way to bled it through that or a better way to bleed it.

There should be an attached image. If there is a better method to bled this please let me know.

Any help is very appreciated. Kind of driving my wife and I nuts. Thank you for your time reading this.

Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks