Main Vent /Steam Pressure Question

Bryan_12

My one pipe steam radiator vents hiss loudly after the system has been running for a while. I noticed that the pressure guage read about 2.5-3 psi, although the Honeywell pressuretrol is set to 1 psi or less (it's set at almost the minimum, which should be good).

Worse, the main vent appears to steady open. It was hissing loudly too. It is in an inconvenient location, mounted in between rafters, attached to a 10" or so pipe to the steam main, but I held a piece of paper on top of it, and the paper got wet. The boiler is requiring regular make-up water to be added. (Hopefully that vent is the only place where steam is being lost). The main line makes a loop on the ceiling, then returns back to the boiler as it slopes generally down.

The boiler is a new Burnham Independence. The boiler water is getting pretty brown, it was last drained and refilled about 2 weeks ago.

Ok, I suspect that the pressuretrol pigtail might be clogged with junk, so it is not sensing the higher pressure and is not shutting off. The excess steam pressure is causing the loud hissing at the radiators (when their vents click open) and constantly at the main vent in the basement. The main vent probably is no good or is maybe clogged too. I'm not sure what the main vent make/model is, it doesn't have a label that I can see. It just looks like a thin cylinder several inches long screwed on to the T extension from the main.

Does my suspiciou sound like what could be happening? I want to tell my landlord so he can have it fixed. He doesn't know a lot about steam. Meanwhile my gas bills are HIGH!

joe_14

sounds like


you are on the right track i would clean the pigtail if not plugged i would replace pressuretrol . and yes i would replace the main vent. you can use a hoffman #75 or a gorton #2 i think



good luck

joeg.

Steamhead

How long is your steam main

and what pipe size?

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Bryan_11

The main steam line is a loop on the ceiling, about 55 feet long, I estimate. Pipe size is about 2"-2 1/2". When we moved in there was no pipe insulation (landlord says he took out the asbestos insulation, [hopefully with a licensed abatement contractor, but I wonder!!!].

Attached is a picture of the main vent. Anybody recognize it ? It doesn't have any markings that I can see, but I can't get eyes close to it b/c of its location. After the system has been operating for a while (e.g. radiators are good and hot, and their vents are mostly closed) the radiator vents really loud (HISS!) when they open, and this main vent in the basement starts venting constantly.

Based with information on this site, I requested that landlord insulate the main steam line and eventually he did. The insulations is only about 1/2 inch thick, but it is much better than it was before.

John Stanley

main vent

Are you sure that's a main vent?

J.C.A._3

Looks like....

A Ventrite either #77 or 57 low pressure main vent.

I think your going in the right direction when looking at the pressuretrol and pigtail. A high velocity discharge after the vents call for more steam is a dead giveaway.
Had one to look at today where this happened, and the loose union connected to the radiator feed was sending steam out hard and fast enough to bend the "filler" piece of wood, to the trim of the nearby fireplace.Apparently enough steam to start peeling the paint off the ceiling 7' overhead. Pigtail stuffed real well. The poor burner doesn't know enough to shut off unless the control can give it proper information. Good luck. Chris

Steamhead

I agree, it looks like a Vent-Rite

or maybe a Dole. It's definitely too small for that main. Use a Gorton #2, and clean or replace the pigtail under the pressuretrol. Then watch how much better it works.

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Bryan_12

A plumber looked at the pigtail

and found that it wasn't dirty. The boiler water on the other hand was pretty dirty and he skimmed it and refilled. I noticed when he replaced the pigtail it is now turned 90 degrees from where it was. So if the pigtail expands a little, the loop will upset the level of the pressuretrol (Honeywell L404). Is this enough to be a problem. He mooved the pressuretrol setting to the bottom of the scale (it was almost there already).

Meanwhile that main vent still leaks a lot of steam after the radiators are hot upstairs. I noticed the pressuretrol did stop the cycle after a while, for about a minute before it cut-in again. That main vent was dumping so much steam though, perhaps that is why the boiler stays on almost all the time. The radiator vents upstairs really hiss loudly, but only after they are hot. Maybe the pressuretrol isn't level?

I need to somehow convince my landlord that he needs to have that main vent replaced with a gorton #2 or hoffman #75. I wish it was my system to have fixed right thanks guys.

Bryan_12

A plumber looked at the pigtail

and found that it wasn't dirty. The boiler water on the other hand was pretty dirty and he skimmed it and refilled. I noticed when he replaced the pigtail it is now turned 90 degrees from where it was. So if the pigtail expands a little, the loop will upset the level of the pressuretrol (Honeywell L404). Is this enough to be a problem for the mercury switch? He mooved the pressuretrol setting to the bottom of the scale (it was almost there already).

Meanwhile that main vent still leaks a lot of steam after the radiators are hot upstairs. I noticed the pressuretrol did stop the cycle after a while, for about a minute before it cut-in again. That main vent was dumping so much steam though, perhaps that is why the boiler stays on almost all the time: enough pressure can't build up even to the 0.5 psi. setting. The radiator vents upstairs really hiss loudly though, but only after they are hot. Maybe the pressuretrol isn't level?

I need to somehow convince my landlord that he needs to have that main vent replaced with a gorton #2 or hoffman #75. I wish it was my system to have fixed right thanks guys.

Bryan_11

Vent Rite 35

The plumber came today to look at the Burnham Independence and steam lines. He took off the old main vent, found that it was leaking, (as I had told the landlord 2 weeks ago ) and replaced it. This time he installed a VentRite #35. I asked him if it was big enough, and he said yes for this size system (which is about a 50' main steam line, about 2 1/2" diameter). He said the #75 vents are really for large buildings and they cost twice as much. Would a larger vent really be too big for this system?

I pointed out that the plumber that came last Tuesday had installed the pressuretrol pigtail so the loop could tilt the pressuretrol , rather than have the axis of the pigtail turned 90 degrees, as it was originally. This pressuretrol has a mercury switch so it needs to be level, and Dan's information says that the coil could cause problems like that when it expands, almost like a thermostat coil. He claimed it made no difference, although he did turn it after I showed him the Honeywell Pressuretrol installation directions with the good and bad diagram

So hopefully this will help.

scrook_2

it looks like

1/2" female & 3/4" male threads on it, so it probably is -- though it sounds as though it has seen better days.

A Gorton #2 (or one or more Gorton #1's or Hoffmann #75's) should do the job.

Bryan_11

Based on everything I've learned from this wonderful website, I figured a Gorton #2 or Hoffman #75 too. The landlord's plumber didn't agree, and installed a "Vent-Rite" #35 saying that those other vents were for large buildings with big mains, etc. Of course he also said it didn't matter what direction the pigtail faced, until I showed him the installation directions. So what can I do? They assume I know nothing, therefore my suggestions are stupid.

This site is great because it lists all of the problems I have had with the steam system (loudly hissing radiator vents, dirty water, loss of water in the boiler, leaking main vent, too small main vent, and especially the lack of main steam line insulation. At least there is insulation now, per my request, and a printout from this site

Dave DeFord

Just a suggestion from a former property manager...

If you want to put some pressure on your landlord you might want to talk to him about how much of your gas bill he is willing to pay because of his lack of action on your requests. You might want to talk to Gorton or Hoffman about the appropriate size of vent for your system. It seems like everyone here recommends Hoffman 75's or Gorton #2's for most houses. LOL

Elias

not to beat the dead horse..

I don't know what that plumber considers a "large commercial building", but when I replaced the little dinky main vent with a Hoffman #75 it made quite a difference and certainly seems like "the right thing". My building is a regular old 3 story building in New York.