2 pipe radiator vents

chadt02

I moved into a house with a 2 pipe steam radiator system. Everything seems to work fine. All of the radiators have broomell unions on the discharge side. They also all had vents installed. After a lot of research on this site, it seems like they should not have vents on them. There is a main vent on the return in the basement near the boiler. It's hard to see but it looks exactly like a hoffman #75. Am i correct in thinking they shouldn't have vents on the radiators? I have replaced 3 of the radiator vents with pipe plugs and have found the site glass on the boiler completely full afterwords. I hadn't seen that happen before. After replacing the vents it seems like more of the radiator gets warm. With the vents it would be hot across the top only. Without the vent the whole thing gets warm.I have attatched pictures of the unions and inlet valves. The unions have plugs in them unlike the picture. I also don't know what my vaporstat should be set at. I assume it's okay, I'd just like to understand the system better. Any help would be appreciated.

Jamie Hall

Nice. No, the radiators should not have vents on them. But the main vent(s) should be bigger -- I'd suggest a Gorton #2 for starters, but after you watch system pressure you may find you need more -- all at that location.

The key to the Broomell -- and any vapour system -- is low pressure. These things were intended to operate on no more than 3 to 4 ounces of pressure; anything more than that will blow steam through the outlet fitting and pressurize the return. It's likely that the vents on the radiators were added in an effort to get heat out of a malfunctioning system.

You didn't show a picture of your vapourstat, so I don't know what it's set at. However, it should be set for starters at a cutout of 6 ounces per square inch and a differential of 4 ounces. It may need to be even lower.

A low pressure gauge -- 0 to 3 psi -- on the same pigtail as the vapourstat would be helpful in getting things set right.

chadt02

Thank you. I’ll check and post what my vaporstat is at now. I’ll replace the rest of my radiator vents. I’ll also try to see exactly what the main vent near the boiler is. I know it’s shaped like the Hoffman 75.

chadt02

There are 2 Hoffman 75 vents on the same return line, about 2 feet apart. And here is a picture of my vaporstat.

chadt02

This is the only gauge on the boiler. Should this be the 0-3 psi? I’ve never seen this one move.

Gsmith

Your vaporstat is set correctly for a vapor/vacuum system. The pressure gage is in fact a low pressure gage, 15 inches of water (the full scale) is about more than 0.54 psi, or a little over 8 oz/square inch pressure. So if your boiler developed enough pressure to have the vaporstat shut it down on pressure (at 6 oz/sq. in.) the gage would read about 11 inches of water column. Seems right for your described system. But, make sure the pigtails on both the vaporstat and the pressure gage are clean so they are seeing the real boiler pressure.

JUGHNE

That is 0-15 inches of water (Water Column). 28" WC equals one PSI, 7" WC equals 4 ounces.

You should see it move.
Have you cleaned the pigtails for both the vaporstat and gauge?
If plugged they can fool both devices.
Unwire and then unscrew the entire vaporstat with a wrench.
You should be able to blow thru each pigtail, might have to remove and flush out, sometimes a large nylon cable tie will go thru for cleaning.

You should see the gauge move if you blow into it.

chadt02

Thanks for the information. By pigtails do you mean electrical connections?

Fred

The pigtails are the looped pipes that the vaporstat and gauge are mounted on.

chadt02

Oh, okay. I assume I should shut the boiler off for this procedure?

Fred

chadt02 said:

Oh, okay. I assume I should shut the boiler off for this procedure?

Yes, power the boiler down so that there is no risk of it coming on while you have it apart.

chadt02

I’ll try cleaning the pigtails tomorrow. Thank you all again, you’ve been very helpful. It’s not easy finding information on this stuff.

JUGHNE

Power off and cooled down a little. After reinstallation of pigtails you should prime them with a little water, you will hear it trickle into the boiler. The water protects the devices from contact with the steam.

Books are available
Start with "We Got Steam Heat" by Dan Holohan, founder of this site. It is written with exactly your situation in mind.
There are more by the same author, but this is the primer.
It is a great read!

chadt02

Thank you. I hesitated to buy the books mentioned on this site because I only need to know about my system and thought there me be a lot of information that doesn’t pertain to me. Maybe I’ll get one anyway.

chadt02

Is the loop in the pigtail intended to be full of water then? Like a sink trap?

Jamie Hall

chadt02 said:

Is the loop in the pigtail intended to be full of water then? Like a sink trap?

Sort of like that. Reinstall the pigtail, then pour water into it until you hear it trickling into the boiler.

And yes, the books have information on other systems than the specific one in your house. Some of it is basic information on heating in general, some basic information on steam heating, and some, based on that, on the specific system you have. I suggest that in order to understand your system, you need the basics as well as the specifics.

chadt02

Thanks again.

chadt02

I cleaned the pigtails today. I couldn't get the one for vaporstat off of the boiler but i was able to blow air through it. The one for the gauge had a good bit of gunk in it. The gauge itself was stuck but after some careful cleaning I was able to get it to move. I poured water into the pigtails and after re-installing everything and turning the furnace on, I saw the gauge start to move. I still have two radiator plugs to install though. I didnt run the furnace long as it was in the 60's here today. Do you think removing the vents will make the system more efficient?

Jamie Hall

Removing the vents may not make it more efficient, although getting the pressure under control will. However removing them will make it much easier to balance and get the rooms the way you want them. Don't remove them, though, until you have vaporstat control.

chadt02

Do you mean once I can confirm the pressure on the gauge matches what the vaporstat is set to?

Jamie Hall

Yes, and that the vapourstat is shutting off at around 6 to 8 ounces. The reason is that at higher pressures than that your return elbows aren't able to keep steam out of the returns, and the returns get pressurized -- so you are running are sort of two pipe/air vent system (which works, but not as well as yours will at low pressure!).

chadt02

I understand. It won’t be too cold here this week but I have a much better understanding of what’s going now. When it does get cold I’ll be able to check and make adjustments if necessary.

Gordo

@chadt02 : I see from one of your photos that you have at least one of your original Broomell valves as well as the Broomell return ells.

I hope you find this posted video of some use:

https://www.youtube.com/watch?v=rj_jK1WTJ1M

If you find it satisfactory, please like, comment, and subscribe on my YouTube channel.

chadt02

I have two of these inlet valves. I’ve been thinking about taking them apart to clean and inspect them. That will probably have to wait until spring though.

Gsmith

@gordo thanks for that Broomell valve video. I have a friend with a Broomell system in Putnam County, NY with all original rsdiators, rad valves and rad return elbows. We have been wondering which way full open on the valve was and thanks to this video we now know. The house heats well surprising since the boiler was replaced a few years back. I haven't explored the basement and boiler piping and would be surprised if the original. Master traps are still there, but when I get back to visit I willnvesrigate.

chadt02

Since my gauge was stuck, if I can’t get it to work properly, can anyone recommend a good replacement? My gauge has no name on it. I looked online for “inches of water gauge” but I’d like to make sure I get the right thing if necessary.

chadt02

I ran through a cycle today and the pressure gauge never got above 1.5. As soon as the burner goes off, the pressure drops to zero.

Mike_Sheppard

Perhaps these will help.

https://heatinghelp.com/assets/documents/312.pdf

ethicalpaul

> @chadt02 said:
> I ran through a cycle today and the pressure gauge never got above 1.5. As soon as the burner goes off, the pressure drops to zero.

Is there something about this that seems wrong to you? Did the boiler run at (possibly) 1.5 psi until the call for heat was satisfied? Or do you mean it would get to 1.5 psi and then shut off, then start up again?

Jamie Hall

You can expect the pressure to drop very rapidly when the burner stops firing -- amazing how fast the steam condenses.

chadt02

It was 1.5” of water. It ran for about twenty minutes. I was expecting to see more pressure than that or maybe a steady rise of pressure until the thermostat temperature was satisfied. I also thought the system would hold pressure for at least some amount of time. If this seems normal, I was probably just thinking incorrectly.

Mike_Sheppard

Do you still have the original Broomell system components? Still connected to chimney?

It was originally designed to not build pressure at all. The basement radiator condensed any steam that made it through the radiators, and if it made it through that it was vented up the chimney.

Jamie Hall

chadt02 said:

It was 1.5” of water. It ran for about twenty minutes. I was expecting to see more pressure than that or maybe a steady rise of pressure until the thermostat temperature was satisfied. I also thought the system would hold pressure for at least some amount of time. If this seems normal, I was probably just thinking incorrectly.

Exactly what it is supposed to do.

In principle, the pressure should rise to a very low level (determined by the flow resistance in the pipes, which is very low) and just sit there indefinitely until the thermostat is satisfied, with no further rise at all. That will only happen if your boiler is exactly matched to your radiation -- you should be so lucky! What happens to most folks in the real world is that there will be that long plateau, then the pressure will start to rise again when all the radiation is full of steam -- at which point you want your vapourstat to shut off the burner. Once the steam is partly condensed and the pressure drops, the vapourstat turns the thing on again to give it another shot of steam.

chadt02

I think the only Broomell components I have would be two radiator inlet valves and all of my radiators have the Broomell elbows on the return. My boiler is fairly new. I can take some pictures of the boiler set up.

chadt02

Thank you for the explanation. I thought if thermostat was calling for heat, the vaporstat would keep the boiler going until it’s settings were met. (6oz. For ex.) unless the thermostat’s temperature was met first. Like, as long as the thermostat called for heat, the boiler would run until it got 6 oz. then stop until it dropped to say 4oz. Then come back on again.

KC_Jones

A vaporstat or pressurtrol are safety devices. When a boiler is sized and set up correctly you really shouldn’t ever hit pressure.

chadt02

Thanks. I didn’t realize that. I assumed it would build pressure to the settings. I should probably get one of those books.

ethicalpaul

> @chadt02 said:
> Thanks. I didn’t realize that. I assumed it would build pressure to the settings. I should probably get one of those books.

This is the way almost all of them run in practice, due to being oversized by 30-50% or more!