New Main Vent Not Making a Sound... Is It Faulty?

HotChocolate1947

I recently fixed (I hope so anyway) a major failure in my heating system. I had to replace two main vents in the basement. One of the main vents does not seem to be making any sounds. No clicks. I stood under the vent during the entire heating cycle and didn't hear a thing. To be fair, it's not too far from the boiler and things are pretty noisy. Is the thing broken? The other main vent is across the room. It makes a very loud clank. It hisses like crazy a few minutes after the boiler stops running. I never paid much attention to the sound of the main vents because they're in the basement. Is this normal?

Steamhead

Shut off the boiler, remove the vent, hold it upright and blow through it. You'll know if it's passing air or not.

pedmec

or you can put your hand on the main at the vent location and see if the steam has arrived at the vent

ethicalpaul

What is the vent? Several main vents don't make noise.

109A_5

Hello HotChocolate1947,

After the boiler stops a vacuum is formed an if the vent starts to cool and open the hissing noise may be the air entering the system through the vent.

Also you could switch them to see if the behavior is the same.

HotChocolate1947

@pedmec You mean I should try to feel for warm air from the vent. It does seem easier than taking it down.

@109A_5 I don't think I should swap them. They are different sizes.

CoachBoilermaker

If the vent was stuck closed, steam would not reach it. So if the nipple and/or body of vent gets hot, you know it is not stuck closed. If it is silent, then good, you know it's not stuck open, and spewing steam.

109A_5

https://forum.heatinghelp.com/discussion/comment/1823387#Comment_1823387

Since they are different sizes the swap would be temporary, however the swap would see it the behavior follows the vent or the main.

pedmec

If it ain't letting air out, you ain't getting steam in.