What Am I Hearing?

Al Hendrickson_26

OK, so what am I hearing? (I have a Burnham I6, manual fill, and a one pipe steam heating system.)

When the boiler starts up cold from a long setback, a minute or two into the cycle, the steam pipes start "singing" quietly. They sound like a water pipe might with a faucet barely open, and the vents start venting quietly. This goes on for a couple of minutes, then intermittently for a few "breaths" . . . and then it stops.

Everything is silent again for several minutes until the boiler actually starts to make steam. Then I can hear the system start to vent again quietly and steadily. After a few more minutes, the radiator vents start clicking shut.

So what is this initial noise? It's not steam. Is it the dissolved gasses leaving the boiler water? Is it the air in the boiler heating up and expanding?

This seems strange. Is this common? I'm puzzled. I hope somebody can shed some light on this!

Thanks in advance!

Boston_2

I hear the same thing from my IN6 and asked the same question

When it first starts up, it sounds like an air leak in the boiler, then after a few minutes it goes away. The main vents puff a few times, and then it’s done. I have concluded that it probably is a little condensation quickly boiling off the inside of the boiler.