Noisy Radiator Vents; Main Venting Problem?

Jeff_H

<span style="font-size:12pt">This is my first winter of house ownership in New York (quite the timing).</span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">I had Vari Values on all of my recessed case iron radiators (I have a one-pipe steam heating system).  Some of them are making noise, usually hissing at the end of the heating cycle when the radiators are warm.  Some spit water (which I understand Vari Values tend to do).  I’ve replaced the noisy vents with Hoffman 1As, Maid-O-Midsts, Gortons and Vent-Rite #1s and the noise continues (the Maid-O-Midsts are the quietest, but spit water). I will check the pitch of these radiators (to see if water in the valves are the culprit), but am wondering if there could be a main venting problem (like Dan’s “too many fans leaving the stadium” analogy).  As the below pictures show, I have an old Hoffman 75 main vent in the boiler room, and there is also a Vari Valve on the other side of the wall that the Hoffman 75 is near. Does this set up seem correct?  I did not see any pipe plugs anywhere, so I don’t think that a main vent had been removed.  Would anyone recommend that I try doing anything else?</span>



<span style="font-size:12pt">Thank you in advance for any advice.</span>

nicholas bonham-carter

Main vents

Replace or add to them with Gorton2's, and check your pressure, and adjust as low as possible, below 2psi.--NBC

Jeff_H

Location of Main Vents

Thank you.  Does it look like the main vents are located properly?

Jeff_H

As an update, I had new main vents installed last year, insulated all exposed pipes in my basement and confirmed that the pressure on my boiler was at a low level. However, some vents still make noise, usually at the end of the heating cycle or after it ends. I replaced the noisy vents with Maid-O-Midsts, which are the quietest, but still noisy and seem to be taking on some water inside of them, although they do not “spit” out the water. I also hear a crackling noise early in the heating cycle on one the radiators (like a snapping rubber band). Could anyone recommend any additional steps that I can take?

Steamhead

The main vent locations will work. Most of us recommend that they be connected about a foot back from where they are now, but as long as there is no water hammer you should be OK.

Measure the length and diameter of each of your steam mains, from the boiler to the two main vent locations. We can tell you what main vents you need.

Fred

Jeff_H said:

As an update, I had new main vents installed last year, insulated all exposed pipes in my basement and confirmed that the pressure on my boiler was at a low level. However, some vents still make noise, usually at the end of the heating cycle or after it ends. I replaced the noisy vents with Maid-O-Midsts, which are the quietest, but still noisy and seem to be taking on some water inside of them, although they do not “spit” out the water. I also hear a crackling noise early in the heating cycle on one the radiators (like a snapping rubber band). Could anyone recommend any additional steps that I can take?

As has been said, put more vents on that Main. Anywhere aafter the last radiator run should work.
As for the cracking sound from the radiator, it is probably just expansion noise. They will do that as they heat up and/.or cool down.
The noise from the vents, at the end of/or after the heating cycle has ended is probably the vent opening as it cools and sucking air in as a result of a slight vacuum, which is more obvious when the outside temps are low and the boiler runs longer. Not an issue and some additional main venting may help even that(if they open before the radiator vents do).