Help with troubling sound in gas heating system

Preble

Our CG Series 12 Weil-McClain gas boiler is making a howling sound periodically which seems to happen shortly after it kicks on. The Weil-McClain service man we hired to look at it is stumped. He says the system is in good working order, but agrees he did hear the noise. They cannot think of what is causing the sound. Everything checks out fine according to them. Two heat zones: circulation pumps OK, pressure OK (supposedly), expansion tank OK. Can anyone help?

Charlie from wmass

Noises are hard to diagnose in typed format

Is the noise from the burner tubes, the piping or the circulator?

Preble

Howling sound

We think it's coming from the boiler box itself. We do hear it through the house (even on the second floor) as if the pipes are carrying the sound, but it is originating at the boiler. We listened to the circulation pumps and they are quiet.

Charlie from wmass

Check for a new company to come out

Like I said it is hard to figure a noise from a message board. It could be the burner tubes. it could be an undersized flex supply to the gas valve, it could also be too high of pressure to the gas train.

Tim McElwain

Does the howling sound

appear when the boiler is first fired up and then subside as the boiler gets hot? If so it could be that it is getting its air for combustion from a cold environment. The howling is a harmonic that is created when the cold air being pulled into the cold burners with a hot flame above the burners. Using a combustion test kit readjust the gas pressure to maximum the burner can handle, do this gradually until the sound stops. Keep CO below 100 PPM at all times. This will probably also increase your efficiency.



Obviously your Weil McLain factory trained service tech will know what this is all about.