Boiler making whistling noise (not kettling)...help please!

jpod3311

Hi All,
I am hoping someone on here can lend their expertise. I have a Weil McLain 68 series boiler, installed in my house in 1992. It's been regularly serviced, and runs well. However, throughout this winter, it has started to make a noise that for the life of me I can't figure out. I've had the local plumber out twice, and they aren't sure what it is, either. It starts shortly after the boiler turns out, and sounds like the whistle that your nose makes when you're stuffy and try to breathe out. The noise sounds like it's coming out of the exhaust pipe, and is quite loud, as we can hear it clearly from our bedroom, a floor above and not directly over the boiler. It's not constant, and earlier this winter was cyclical almost like a police siren, where it goes on and off. Throughout the winter it's gotten worse, and the noise continues practically for the duration of the cycle. Once the boiler kicks off, the noise goes through a few cycles of something like a cat making a loud meow...nothing, then loud, then fading. This happens 2-3x after the boiler turns off.

I've recorded an audio file of about 15 seconds of the boiler running, then 30 seconds after it kicks off so give you a better idea of the sound I'm talking about. Unfortunately, it doesn't look like the forum will let me upload it. If there's a way that I can post the audio file, that would be great because I'm sure it'd be more helpful than my blathering.

Any thoughts or feedback would be highly appreciated, and I'm happy to answer any questions, as well! Thank you very much!

Fred

It sounds like the boiler has a leak in it above the boiler water line and what you are hearing is steam escaping and probably going up the chimney. Let the boiler cool down and over fill it up to the risers that feed the mains. If water spills out, you can stop this test and call someone in to see if the leak is in the top of the boiler block (most likely) or in a pipe.

EBEBRATT-Ed

What @Fred pointed out is a possibility. Steam escaping making one noise and a vacuum when the boiler shuts down making a different noise.
Gotta get the cat out of that boiler

jpod3311

Thank you both! I'll look into that as a possibility