Radiators making a whooshing sound

Fmassarotto_9

2 radiators started making this sound a few days ago 
https://youtube.com/shorts/JGgMroz2AUA?feature=share.
What could it be? I thought it was air but when i my finger above the hole, my finger gets a little damp 

ethicalpaul

It probably is air, but it might be steam. Is the vent hot to the touch (like too hot to hold onto)?

Every time your boiler starts, it has to push the air out of the pipes and out of the radiators, and a lot of that air has to escape out of that little hole.

Then at the end of the heating cycle, air has to go back into the radiators and the pipes.

So during these times, you will notice air coming or going.

The only thing really to be worried about is if it is actually steam escaping from the vent. If so, then you replace it.

Fmassarotto_9

ethicalpaul said:

It probably is air, but it might be steam. Is the vent hot to the touch (like too hot to hold onto)? Every time your boiler starts, it has to push the air out of the pipes and out of the radiators, and a lot of that air has to escape out of that little hole. Then at the end of the heating cycle, air has to go back into the radiators and the pipes. So during these times, you will notice air coming or going. The only thing really to be worried about is if it is actually steam escaping from the vent. If so, then you replace it.

so if you look back at the video you can see water like bubbling out of the top, im assuming it's steam, either way the vent becomes like fire, it can't be held 

ethicalpaul

OK if the vent is hot, it's probably steam and vent is either failed open, or the pressure is too high and forcing its way out (but it doesn't seem too high in the video...but it's hard to tell).

But water bubbling out the top is not enough of an indicator. Things can cause water to bubble out long before steam fills the radiator.

Fmassarotto_9

ethicalpaul said:

OK if the vent is hot, it's probably steam and vent is either failed open, or the pressure is too high and forcing its way out (but it doesn't seem too high in the video...but it's hard to tell). But water bubbling out the top is not enough of an indicator. Things can cause water to bubble out long before steam fills the radiator.

im thinking it's likely pressure then since the vent is only a month or two old. but the possibility of it failing already certainly isn't impossible. But if it is pressure i'm in a bind because lowering the pressuretrol anymore causes the boiler to cut out  when the pressure is reached and it doesn't fire back up. It's right at that point where it cuts out when it should and cuts in when it should. i also cleaned the pig tail and all the connections before the heating season and made sure i can blow freely through the pig tail 

Chris_L

I'd say that vent isn't sealing well when it closes. That is what they sound like. It is not that it has failed open. It just doesn't close completely when steam hits it.

I suspect if you carefully unscrew the cap when it does this, it won't affect the amount of steam coming out.

When I've had this problem with Maid O'Mist vents, I just called them and they sent replacements.