Air vents hiss whenever boiler is working

heatinghelp819

@fred not sure how to message you then. when I click on your name to see your profile and send you a message, the profile is basically blank, so not sure what's happening. are you able to message me?

Fred

@heatinghelp819 , I sent you a PM. Hopefully you got it. I also sent @Erin Holohan Haskell a PM to ask if she could check too.

Abracadabra

not sure if @fred is the same as @Fred.
When i click on each I get a different profile

Fred

Abracadabra said:

not sure if @fred is the same as @Fred.
When i click on each I get a different profile

So strange @Abracadabra and @Erin Holohan Haskell , when I click on either of those, neither is my actual profile ????

LionA29

@Fred , the second one is correct (Fred) not fred!
@Abracadabra you have to type the person's EXACTLY as they appeared in their profile. Just saying

Abracadabra

When you start to type "@F" two @Fred @Fred show up

Fred

LionA29 said:

@Fred , the second one is correct (Fred) not fred!

@Abracadabra you have to type the person's EXACTLY as they appeared in their profile. Just saying

LionA29 said:

@Fred , the second one is correct (Fred) not fred!

@Abracadabra you have to type the person's EXACTLY as they appeared in their profile. Just saying

Again, strange, neither are my profile when I click on them (in Abra's) post. They both come up as a Profile that has no activity and neither has my posted photo.

LionA29

I've tried it and it's is what I mentioned. Maybe sign out and then back it to reset your browser. STRANGE!

Fred

LionA29 said:

I've tried it and it's is what I mentioned. Maybe sign out and then back it to reset your browser. STRANGE!

Erin is working on it. I have had this issue for the past two or three months. The only way I can get to my actual profile is to click on my name in the black area at the top of the page. If I click on my name in orange, lower down on the page, I get a different profile that has no activity in the profile. We' see what she finds.

Erin Holohan Haskell

Thanks for the additional info. We're looking into a fix and I'll keep you posted. Thanks for your patience!

Erin Holohan Haskell

How is it now? Are you still seeing anything odd?

nicholas bonham-carter

I don't see the statistics for all my posts, or my many badges!--NBC

Abracadabra

all the fred's look the same to me. and it's the right one now.

Erin Holohan Haskell

@nicholas bonham-carter - Please send me a message and let me know what browser and OS you're on. Thanks!

Fred

Erin got my all fixed up!

heatinghelp819

Well we had a very warm day the other day (59 degrees outside!) and the vents were still doing the same thing - letting out lots of air. Any other thoughts on why this could be happening are welcome!

Fred

@heatinghelp819 , are you 100% sure the hissing is at the beginning of a heat cycle and not just after the boiler has shut down? Sometimes when a heating cycle ends, there is enough vacuum buildup in the system that it will pull radiator vents open and suck air back into the system. I can't imagine that the boiler would run long enough on a 59 degree day to build enough pressure to cause the vents to hiss, unless you are using a deep set-back and the boiler runs for an extended period or the man venting is inadequate. Did you get the new vents added to the mains? Do you have any of the radiators shut off? Each radiator that is shut off will make the boiler larger than the remaining connected EDR.

Abracadabra

What size vents are on the radiators?

heatinghelp819

Setback is only 3 degrees at most at any given time, but this happens any time the boiler turns on, even if going from 73 to 74 degrees. And yes, it is when it turns on, not the vacuum when it shuts off. The hissing lasts for several minutes (not sure exactly if it stops when the boiler shuts off b/c it reached temp, or before).

I added the B&J Varivents to the mains, and as I mentioned (sorry this thread is so long and chock full of info), in the one week or so between the awesome boiler clean that Dave did and the installation of the B&J Varivents, there was no hissing. The hissing started up again after I changed the main vents from my Gorton 1s to the Varivents.

All rads are fully on. And they all have different sized vents, and almost all are doing this.

Fred

Did you lock the varivents in, using the set screw? Is it at all possible you maybe locked them in closer to the closed position rather than the open/near fully opened position? How long are your radiator run-outs/risers? Are they unusually long or tall holding more air than typical? I'm running out of ideas here. Those varivents have much more capacity than the Gorton #1's. they should have helped a lot.

gfrbrookline

Can you define hissing? Is it just a slight noise like air coming out of the vent or is it a whistle like steam coming out of a tea pot? if it is a faint noise that is normal, air is just being exhausted from the system. My boiler has a hot water loop and an additional feed for DHW. In the heating season I leave the hold temp set at 180. Every time the boiler kicks on I hear what sounds like air exhausting from the vents when the burner is on but the rads dont get hot nor does my near boiler piping. I chalk it up to the system breathing. I also cant feel any air coming out of the vents.

Abracadabra

I'm guessing that the main varivents are not set properly.

heatinghelp819

How does one set them properly? The top part screws up (and off) or down; the manufacturer told me up is open and down is closed. I have it about one or two turns lower than completely up and off the vent, in other words it is nearly as open as it can be. Is that wrong?

The rads are hot when the vents hiss. there is not steam coming out of the vents, it is air.

I do not know how long my run outs/risers are.

Could the narrower-than-ideal width/size of the near boiler piping be causing this? (As Dave had mentioned in an earlier post: The near boiler piping is not helping matters as the plumber only ran one 2" riser into a 2" header, were the manual calls for a MINIMUM of one 2-1/2 riser and header. Steam exit velocity with the single 2" riser is around 44 feet per second. With the 2-1/2 riser and header velocity will drop to 30 fps, still waaay higher then we'd like to see at around 15 fps. )

heatinghelp819

Can you explain how the B&J Vents wouldn't be utilized properly? What does that mean?

heatinghelp819

In case it helps, here is a video of some of the hissing on one rad
https://www.youtube.com/watch?v=gC9cFno7ZuM&feature=youtu.be

Abracadabra

Does the vent huff and puff like that constantly? Either you have a sag in a main somewhere that is causing steam to collapse or your mains are uninsulated.

heatinghelp819

@Abracadabra yes they do that whenever the boiler is on pretty much. The mains do it too. What is a sag in the main and how do I determine if that's the case?

I guess at this point I will try to put the old
Gorton's back on, though I'm not confident that I didn't ruin them when trying to get them off, and I'm not that excited about shelling out another $1-200 for new vents.

Abracadabra

Sag.. the pipe has sunk downward in some spots trapping condensate. Are the main pipes insulated?

Fred

That's not hissing. Not what you get when pressure is the issue. Hissing is a steady blowing, like air is being forced out of a vent faster than the vent orifice can handle it and it is a consistent stream of air. What kind of vents do you have on those radiators? It almost sounds like an echo chamber to me. Like when you blow into a can. The air that is blowing through the vent is hitting the interior wall of the vent. Is the vent an angle vent or is the part that screws into the radiator on the back side of the vent? If so, try an angle vent like the Hoffman 1A or Vent-Rite #1. They tend to direct the air up and out the vent rather than against a more hollow circular type vent. It is venting air, which it is suppose to do and until the radiator is hot, all the way across it will stay open and continue to vent. I'm thinking it is the design of the vent you have on the radiator relative to the style of radiators you have. Try one with a Hoffman or Vent-Rite and see if that quiets it. If so, replace the others.

Sailah

If you have the cap unscrewed on the varivent to the point if you unscrewed it one more turn it would come off in your hand, then yes it is wide open. Have you tried a different position like say 50%?

Something doesn't sound right in your system for this to be happening. Can you have the original contractor out and have them look over the basics?

heatinghelp819

We have Gortons (diff sizes) and some old varivents on our rads (that look similar to the attached image). I'm pretty sure both types are making this noise but will give it a closer listen.

Mains are insulated. I don't see any sags.

We just moved in 18 mos ago. The house was built in 1937. Not sure who put this boiler in so can't contact the original contractor. And yes vents are fully open, and I've tried them a little less open as well. Same issue.

To recap: this noise first started a couple months ago after we repaired two leaky radiator valves. I assumed the air now coming out of the rad vents had been coming out of the leaky valves, so fixing them forced the air out of the rad vents. But the problem also went away after, most recently, we cleaned the boiler and recalibrated the pressuretrol. It only again came back after switching the Gorton 1 main vents to B&J varivents.

LionA29

According to the video provided, that venting is really " blowing". Did you discuss boiler pressure?

BobC

Its sounding like the boiler is operating at a higher pressure than it should be. You can't trust the 0-30 pressure gauge, make sure that pressuretrol and pigtail are clear. Some sludge might have floated into the pigtail.

Bob

Abracadabra

@heatinghelp819 the huffing and panting in your video indicates that steam is collapsing significantly as it's going out from the boiler. You need to vent the radiators slow and the mains fast. You usually will not "see" sags in the mains. check with a level. Look for missing hangers. Also as others have said, you need a lower pressure gauge to really view pressure. something in the 0-3psi range. the 0-30psi gauge is useless.

Fred

I may be missing something. I know my hearing isn't what it use to be but what I hear is not a radiator vent being over whelmed by pressure. I really think we need to move past the search for a pressure problem and onto the next possibility. We need to validate or invalidate the condition that @Abracadabra suspects and we need to consider the vents themselves. We all know the verivent radiator vents vent too fast and depending on the size of the Gortons, they may be also, especially for convectors. It just doesn't sound like high pressure to me.

Dave0176

Hey guys I adjusted the pressuretrol and recalibrated it as it was waaay off from the factory. It now trips at 1.5 psi and and back on at .5 The boiler is oversized for the house 337 connected load to 454 boiler output. There is a single small 2" riser into a tiny 2" header. The cycling and over pressures Connot be avoided.

I informed the HO about stage firing the burner but she is hesitant about the safety of it. I explained it is very safe and we even verify that with combustion testing equipment, but I can only lead a horse to water.

LionA29

Great work @Dave0176. I'm sure you did your best!

heatinghelp819

I really appreciate all the help from everyone.

I am confused about the boiler size though; @Dave0176, I thought you had determined earlier that the boiler wasn't oversized? (thus not needing downfiring). Is the size again a reason for the noises? If so, why would there have been a hiatus in the week between the boiler clean and replacing the main vents?

I'm also now hearing loud bangs coming from pipes somewhere when the boiler comes on sometimes - like someone banging on the metal. This keeps getting better and better!

Fred

Well, if you hear banging shortly after the boiler fires, and I assume it's making steam ?? that's a pretty good place to start looking for a sagging pipe or mis-pitched pipe that may be holding a little water like @Abracadabra suggested earlier. That will contribute to the vent noise but may not be the entire story. As @Dave0176 indicated , he re-calibrated the Pressuretrol and it cuts out at 1.5 PSI so we know the vent noise isn't from excessive pressure. Of course, if the boiler is over-sized, it will short cycle, based on how long it runs during a heating cycle but that, by itself doesn't contribute to bent noise. Having said that, it is clear that a single 2" riser out of the boiler and a 2" header has most likely created a situation where the steam velocity is much too fast, not allowing the water droplets to fall out of the steam before it is carried out into the system. That will create wet steam and may also contribute to venting issues and will exacerbate the amount of condensate/water that needs to move back to the boiler .
Have you had any discussion about repiping the boiler to allow for both riser tappings to be incorporated into a larger drop header? A two stage gas valve should also be considered, in addition to the repipe if the boiler is, in fact over-sized. I'm now confused about the sizing issue too.
My theory about you not having any noise for that one week period before you put the B&J Vari-vents on is that the Gorton #1's were small enough that they actually caused the steam to move more slowly down the mains trying to push air out of them through those under-sized main vents. Putting them back on (along with finding the banging pipe) may quiet your radiator vents but there is a trade off there as well. Using under-sized main vents contributes to increasing system pressure, causing more short cycling and taking longer to utilize the steam for its intended purpose, to heat the living spaces. Sorry for the long post!

LionA29

I think the OP needs to communicate with @Dave0176 again so he can properly address his issues. Sometimes it takes a couple approach to rectify Steam. There isn't always a one time fix. What I have learned is that it takes a lot of patience to get it right And I'm absolutely sure @Dave0176 will fix you up.
Let us know your progress.