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Joined on October 21, 2011

Last Post on September 16, 2014

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Hoffman #2 Vacuum Vents

@ January 12, 2012 10:30 PM in Hoffman #2 Vacuum Vents

I just read this:
Why aren't all steam vents made this way? Why isn't this vent available any more? Sounds like a no-brainer to me.


@ January 12, 2012 10:26 PM in Pushing the envelope with a pressuretrol

I'm not sure that they are reliably repeatable at that low a cutin.


@ January 12, 2012 9:42 PM in Wika 3 psi gauge

I just read that book.  Why aren't more vents like that?


@ January 12, 2012 9:27 PM in Steam newbie with some questions-boiler short cycling/main venting/etc

Depends how the thermostat was wired in to control the boiler.  I've seen thermostats wired so that that start the cycle, but the boiler would shut down on pressure or an aquastat on the furthest return line.  

Need to know what pressure is doing.  Get a good 0-3psi gauge and watch it.  When does boiler shut off and when does it turn back on.  You might to to adjust the cutin and cutout of the pressuretrol.  I'd find out how the system works before you make any wholesale changes.  Set the vents upside down for now till we figure stuff out so that lady on the end unit doesn't freeze :-)
That exetech is a usb temp logger.  You leave it in the apartment for a few days, collect it, stick it in your computer and it'll graph the temp over several days.  You can set it to take temps every 5, 10, 20, etc... minutes. Saves 30000 points. Wet returns don't get vented.  The dry return (end of the main) just before it drops down to the wet return should be vented. Deadmen should have installed vents. I'd follow the main along and see where it goes and before it drops down to the wet return you should have an side-inlet elbow or tee with a spot for a vent.
Pressure is 2lbs.  But is that the cutout? cutin? 2lbs is s bit high  but still should work.  Pressuretrols are not made to control boilers.  They are there to shut it off in the case something goes awry and you need to shut it down. Need model number of the pressuretrol.  Take pics of the dial inside with the cover off.


@ January 12, 2012 9:06 PM in Steam newbie with some questions-boiler short cycling/main venting/etc

meh.. site isn't letting me edit my post.

that first sentence was supposed to be "You need to figure out what is turning off the boiler"


@ January 12, 2012 8:54 PM in Steam newbie with some questions-boiler short cycling/main venting/etc

#1 - You need to turn off.  A safety? Pressuretrol? Water dropping low? What's the pressure? 
#2 - I never (rarely) believe what a tenant tells me.  Are all radiators in her apartment getting hot evenly with the rest of the radiators in the apartment?  A temperature logger like this: is invaluable in tracking exactly what the temperature is in a multi-unit property.
#3 - Usually you want to vent the radiators in the apartment with the thermostat real slow so that you make sure that the rest of the units have gotten heat. Sounds like they took the cheap way out to slow down the venting there.  Actually, upside down, the vents should not vent at all and you will basically be overheating the rest of the building.
#4 Your underground line sounds like a wet return.  But then you saay "traps".  Are you sure you have traps?  Traps are used on 2-pipe systems.
Pics are always helpful.  Take pics of near boiler piping, vents, drips, dry to wet return transitions, and enything else you think would be useful.

Drip that "U"

@ January 12, 2012 7:59 PM in five cold radiators on three risers, I'm scratching my head

"After a while (over an hour) one of the problem radiators heated a little bit and the riser at the inlet for that radiator made a continuous watery sound that reminds me of gargling. I have no idea what this means"

Water is collecting somewhere and steam is trying to get past the water, giving you the gurgling sound.

Does the main from the left get vented anywhere?  I'd bet it doesn't since it loks like originally it was meant to continue on to the left.  Does the main from the right get vented anywhere?
 I opened the bottom of the "U" pictured and drained about 5 cups of water 
That "U" you drained filled up with more water from condensing steam from your uninsulated mains within 5-10 minutes after your boiler started steaming on the next cycle. 
Do this as a test.  Follow the steam along the pipe  with your hand.  You will feel the TOP of pipe get hot.  The bottom will get hot with hot condensate. Follow the steam and see where it stops or slows down.  Time how long it takes to get from the header of the boiler to the takeoffs to the risers.
Pics of near boiler piping? A diagram of your main lines? Vent locations?

basic leak check

@ January 12, 2012 7:47 PM in Thinking about buying a used boiler.

At a minimum, verify the boiler works while it is still hooked up to the old house. Watch it run thru a cycle. If there's a autofeeder, see if it feeds a lot of water during a cycle, which could mean that it's been fed lots of water in it's lifetime which can deteriorate cast iron  sections. Fill the boiler with water to the header and let it sit there for a while and see if you have any leaks.  Not sure about which Peerless you are looking at, but some Peerless I know have neoprene gaskets on the sections.  


@ January 12, 2012 7:38 PM in Location for #2 radiator vent

#1 - How big is this radiator?  Can we have a pic from the front?  Height? Width?

#2 - What is the size of the riser? If you are on the third floor, I'm guessing the riser is about 20-22 feet long.
#3 - Once steam hits the radiator, the condensing steam will create a vacuum that sucks more steam into the radiator. Don't worry about the volume of the radiator.  You won't know how it works till you try something.  You can always adjust a vent up or down.
I'd vent the riser with a Gorton or MOM "C" placed on the valve side of the radiator. I'd vent the radiator with a Gorton or MOM #5 to start and see how that works. Yes, use radiator vents.  No need to use a main vent on the riser.  Besides, main vents are 1/2" or 3/4".  Tapping on the radiator is 1/8"

vent rads slow

@ January 12, 2012 7:30 PM in Help identifying steam vents

"not follow the recommendations from the gorton website as to radiator vents."

+1 for this.


@ January 12, 2012 7:28 PM in Boiler block cracks

where's the pics?


@ January 12, 2012 7:26 PM in Wika 3 psi gauge

When steam condenses it creates a vacuum.  It's part of what makes a 1-pipe system run.  After all your pipes and radiators are hot, all vents shut.  When the boiler ends it's cycle, steam starts condensing.  Remember, vents are all shut because they are shut and they don't reopen until they cool off.  Depending on the brand they make need to cool off to 130 or 140 to drop out.  Gorton G2s are notorious for this. Steam condenses at a temp under 212. Steam condensing, no air entering your pipes of radiators means a vacuum has to occur.  I see a vacuum at the end of a cycle as well.  I don't think it will harm the gauge as long as it's not excessive.
The gauge should show 0 when boiler is cold and that ball valve you have is open.  I'd like to have a little more height for the gauges off the pigtail than you have there.


@ January 12, 2012 9:06 AM in Wika 3 psi gauge

When do you see the vacuum? After a cycle and the boiler cools down? That sounds normal.  Especially if your vents aren't opening up after the cycle. I've seen some vacuum breaks posted on here. Don't recall where though, sorry. 

When you shut the valve, was the boiler & pigtail hot?  If so, that will give you some vacuum when everything cools down.


@ January 12, 2012 8:51 AM in Rethinking 1-pipe steam venting strategy


Yes, this is that building that's hardly getting any steam at the last few rads. I was actually hoping to use something between a MOM #4 and an MOM #5.  I'd prefer to not have to go back and replace all the new MOMs.  I'm not worried about shutting down on high pressure.  Burner is hi/lo fire and vaporstat is set to 6oz cut-in and 12oz cut out.  I can lower the cutin if needed. The owners have invested about $1600 in new vents.  I can get replacement orfices for the MOMs for  about 90 cents. If the MOM #4 prove to be too slow for some I was thinking of drilling the orfice with a bit somewhere between a #4 and a #5. A Watts SV lands somewhere between a #4 and a #5, but I'm hesitant to use a Watts as I've had a few small problems with them in the past. Also, not worried about venting the unit with the thermostat too slow.  The building is controlled by a unique system that measures temps across 7 different units and averages them to come up with a "average building temp". Basically a multi-zone thermostat. I can access the control remotely and have written an app for it that will take readings every 15 minutes and allow me to graph the apt temps.  I can easily use that data to create a graph of the differential temp of each unit from the calculated average.  When I find one that's above the "building average" I'll slow down it's vents.

yes? no!

@ January 12, 2012 8:35 AM in VisionPro 8000 settings

"but I was probably not listening."


vent your radiators slow

@ January 12, 2012 8:31 AM in Location for #2 radiator vent

"Vent mains and risers fast, vent radiators slow"

That is all.


@ January 11, 2012 10:05 PM in How many CFM of steam does a certain boiler make?

thanks bob!

doubt it will work at 1 oz.

@ January 11, 2012 9:14 PM in Location for #2 radiator vent

what type of a steam system is this? If it's 1-pipe, I seriously doubt it will work well at 1 oz. 

How many CFM of steam does a certain boiler make?

@ January 11, 2012 9:00 PM in How many CFM of steam does a certain boiler make?

All in the title.

Is there a way to calculate how many CFM of steam does a certain boiler make? Ignoring the effects of condensation.

Rethinking 1-pipe steam venting strategy

@ January 11, 2012 8:18 PM in Rethinking 1-pipe steam venting strategy

I'm doing a complete revent tomorrow of a third building. 19 unit building, 4 rads per unit.  I'll be changing out 76 vents.  On the first 2 buildings I did last month, an typical  venting strategy has caused me some balancing problems.  I'm using MOM vents on the rads and Gorton 2s and 1s as needed on the mains. Yes, I quickly vent all the mains, the longest mains with multiple G2s.  Mains fill with steam within 4 minutes. Just about as fast with an open pipe at the vent. But  for 1-pipe systems with this many radiators the typical venting idea that most rads get 5s, larger rads get 6s, far/cold rads get C and small rads or rads in rooms with the thermostat get 4s, and maybe far/cold/rads on the third floor might need to be stepped up one step to vent the riser, the amount of radiator venting exceeds the venting available at the mains.

Just as an example, I added up the main venting on one building. total venting on the mains is 5 G2 and 2 G1. This is 6.16 CFM at 1 oz.
The 76 vents on the radiators vent at 7.216 CFM at 1 oz. And if you calculate the radiator venting at 3oz  it comes out to 21.702 CFM.  I believe that this is too much venting on the radiators. I have decided to try a more conservative (aka slower) venting strategy on the radiators on this third building. All radiators will be getting MOM #4 with the following exceptions. Add 1 size for 3rd floor rads.  Add 1 size for "very large rads".  That's it. On this building I'm doing tomorrow, that give me total radiator venting of 2.08 CFM at 1oz and 10.6CFM at 3oz.
With the additional "backpressure" I should be able to get steam to go where I want it to, not where it wants to.
Any comments?

adding a second vent

@ January 11, 2012 7:25 PM in Location for #2 radiator vent

Isn't there a spot for a vent on the valve side (opposite side from your picture) for a vent there?  the end sections for radiators are usually the same.  You can add another D to that valve side.  The benefit is that once the riser is vented and steam hits the first section, you close up that vent and vent the radiator just using the 1 D on the far side.

tenant is now cold?

@ January 11, 2012 7:20 PM in more venting, another rad, and / or bigger pipe?

she probably "feels" cold because it was so hot before ;-)
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