Main Venting - 3 Loops, vents over boiler

Jared_2

I just purchased my first home a couple of weeks ago and it has a single pipe steam heating system. Prior to this I had zero experience with steam heat, and I've been bouncing around this site off and on over the last few days and have learned a lot. (Thanks, great info here) I also ordered the book, and plan to read it, but in the meantime with the wx forecast not showing anything above the 20's for at least a week, I would like to start getting better performance from my system.



Problems:

1. Many radiator vents whistle loudly, spew a little steam, or don't at all so the radiator remains cold. - I plan on replacing most all of them as I have already tried cleaning, with limited success, and they are all either old or the HDepot "adjustable" kind. Based on other info on this site I'm going with Gorton's and feel fairly comfortable picking which ones.



2. The mains seems to vent really slowly. This is where my question comes in. In looking around, I haven't seen a system like mine discussed on here, or at least haven't been smart enough to recognize it. There are three main lines, which loop out (2in) and back (1in) with their vents back over the boiler. One line, the longest also has a vent at it's extreme end. Based on what I have seen, the length of these loops (60', 70", and 106') is really far, especially for the vents installed (Dole No. 1933)



I think in an ideal world the vents would probably be at the end's of loops, but there doesn't seem to be a place for them there. (also there probably would only be two loops, one was added a long time ago with an addition, and now there are risers that seemingly go nowhere.) I've learned on here that you really can't vent the mains to much, but the challenge I face in the short term is the existing main vent taps. All of the Dole vents are 1/8" in size, which pretty much leaves me with a Gorton D as far as I can tell.



Is installing 4 Gorton D's in the existing spots worthwhile or should I save my money and hire someone to install different hardware so that bigger vents can be installed? Is simply stepping up from a 1/8" connection to a larger size ok or would the small pipe overly limit the vent flow? I attached a crude diagram and some pictures in case they are helpful. The 4th main vent is way back in a crawl space at the corner of the house, so no picture of it. I only want to go back there once to change it out. Any other thoughts welcome as well. Thanks for your time.

nicholas bonham-carter

Improving the venting

First, do not follow the advice on the gorton website, as they make good vents, but have no idea how to use them.

The main vents you have are probably screwed into bushings which must therefore be removed in order to put in the gorton 2's you need (maybe more than 1 each dry return). The bushing will have flats on it and be difficult to remove, but not impossible. Put some penetrating oil, like kroil or PBS blaster on the threads, and use an open end wrench on the flats, with a hammer. Light to moderate to heavy tapping will shake the bushings loose.

An antler will give you room for adding the extra vents you may need.

A 0-3 psi gauge will show you when you have enough vents, by reading the back-pressure of venting. This low pressure will show you that you are not paying for extra fuel to squeeeezzze the air out of constipated little main vents.

Make sure the radiator vents are slow, such as Hoffman 40, or the gorton equivalent. Later on, one or two may need to be enlarged if the riser to radiatorAs very long.

Keep the pressure low as the steam heats better at 6 ounces.--NBC

Rod

Main Vents

Hi- Welcome to the Wall. I’m glad to hear you have ordered the books they will be a great help you.

Main Vents- I looked at your pictures and tried to get a reference to judge the pipe sizes . They look bigger than 1/8 inch to me. You might want to check  the sizes.  I ‘ve attached a table The easiest thing to do is measure the circumference and then compare it with the table to find the pipe size. Use a strip of paper and wrap it around the pipe and make a mark where the end of the paper touches. Then use a ruler to measure the length.  They also look like they are bushed down to a small pipe for the vents. It might be possible to remove the bushes to increase the vent pipe size.

 

A lot of main vents have a combined 3/4 male pipe thread on the outside and ½ female thread on the inside so that they will attach to either 3/4 or ½ inch pipe. A few figures for comparison to help you/

The most common main vents used by the Wallies are  Gortons and Hoffmans

A ½ pipe has the capacity to  support 2 ea. Gorton #2 main Vents.

1ea. Gorton #2 has the venting capacity of 3 ea. Gorton #1 (s)

1 ea. Gorton #2 has the venting capacity of  2 ea Hoffman #75 (s)



The Gorton #D has the same venting capacity of the Gorton #1



The Gorton #2 is quite tall 6 + inches so that needs to be a consideration if there isn’t much clearance above the pipe.

Ideally the main vents go just after the last radiator lateral though they are just as acceptable at the end of the dry return where yours are located.

You can’t over vent steam mains but you can definitely over vent radiators!!



Radiators- Make sure the steam valves on the pipe going into the radiator are fully open otherwise the steam coming in and the condensate going out collide. One pipe radiators should have a slight slope towards the inlet pipe,just enough to “encourage” the condensate (water) to leave the radiator. Use a carpenter’s bubble level to check this. You can use wood shims under the feet of the radiator to get slope. Also Home Depot has little plastic wedges available (Toilet Wedges) available in the Fluidmaster Parts section in the plumbing department.

Hissing may mean the pressure is too high. Residential steam systems operate at a maximum pressure of 2 PSI.  On radiator vents you might want to start out with Gorton # C and adjust up or down on  the individual radiators that need it.

A good source for Gorton and Hoffman vents is you local heating supply or Pex Supply on the internet  www.pexsupply.com

I’m sure you have questions .Let us know what they are and we’ll do our best to answer them.

- Rod

 

Jared_2

Thanks for the quick replies

One of the Main vents, at least of the three visible ones, is in a bushing. The other two are just 1/8" taps out of the 1" dry return pipe elbow. I'm sure there is a term for it, but you can see what I mean in the first picture, where the dry return line turns down there is a flat place on top, the hole in that flat place is only big enough for a 1/8" pipe right now. That's what I meant when I was talking about 1/8" pipes. I double-checked the diameters with the circumference guide and all were correct. 2in mains out, 1 in dry return, 1/8" nipples off for the main vents.



Given that, and the fact that I don't want to stir stuff up too much until i can do something about the lagging and mud-like coating on the elbows (99% sure it's asbestos), would using a bell reducer backwards (so like an expander) to convert up from 1/8" to 1/2" for a single Gorton #2 work ok? I recall seeing somewhere else on here that the capacity of a 1/8" pipe and a Gorton #2 were about the same at these low pressures. Once the asbestos is gone, and I'm not relying on the system for warmth, I can add more capacity later right? I would just need to make a larger tap for a larger pipe, then add the antler & additional vents.



Other Questions:

- Of the three visible main vents, two have the pipe nipples extending them up and one doesn't . Does this matter? Space for the #2's shouldn't be a problem, but on the two that have the long nipples extending them up, it might be a little tight.



- WRT the main vents, will it throw the system balance off to have the two main vents for the long main line in difference places? (One at the end of the dry return and one at the end of the loop) The total air volume in the pipe is approximately double, but of course most of that is on the way out in the two inch section of the loop.



- For the radiator vents my plan is to calculate, for each radiator, all of the air in the risers plus the air in the radiator itself and try to select the vents proportionally based off that. There are a lot of different sized radiators in the house and some long risers and I thought that would work better than trial and error based off a starting point of all the same vents. On that note however, 5 of the 11 radiators are the fin pipe baseboard style radiators while the remaining 6 are all various sizes of cast iron small tube radiators. Should I factor this into my vent selection for them at all or just continue to base it solely on internal air volume? I know there heating up & cooling down properties are very different, and ideally they wouldn't be mixed. FYI it's all cast irons upstairs with the fin pipes and a couple of cast irons downstairs.



BTW, I'm calculating the rough internal volume of the radiators from their EDR and this chart: http://www.gwgillplumbingandheating.com/webapp/GetPage?pid=237



Thanks for all of info so far, it has been really helpful in bringing me up to speed.

Rod

Venting

Hi- You’re correct at low pressure a 1/8 pipe theoretically has the capacity to vent a Gorton #2. However the 1/8 inch pipe doesn’t have the size to handle both air and to be able to drain off any condensate (water) that gets near the vents.  While it would probably work at a short gap measure in the long run you’d want to go to a ½ pipe minimum.



When attaching vents to the steam main the important thing is to locate them so that any water reaching them will drain away.  If you have overhead clearance  mounting them on a long pipe nipple works well.  If you don’t have clearance using an antler works well. Orient the antler so that it is up slope from the vent hole in the main. This promotes drainage and slow down any water as it has to turn 180 degrees to reach the vent.



Multiple vents on one main should be okay. As mentioned before ideally the main vents should  be located just after the last radiator lateral on the main. Why vent all the rest of the piping?



Radiator Venting- I’m not sure whether there is much benefit in calculating the radiator volume as I haven’t found volume all that helpful. While it would seem that the faster you get the air out of the radiator the faster things would heat up this is always the case and sometimes using slower (lower capacity) vent actually speeds things up.  EDR is handy to know. I’ve attached a form on how to do calculate EDR.

You want to have lots of main venting capacity so your steam mains will be completely filled with steam before any reaches the radiators.  The last thing you want is the steam sequentially filling the radiators as it slowly moves down the steam main. This leads to “hogging” where the radiators closest to the boiler use all the steam and the smaller radiators farther down the line get very little. Here a link to info on venting I wrote up to answer a venting question some time back

which might be of help to you.

- Rod

Hi- You’re correct at low pressure a 1/8 pipe theoretically has the capacity to vent a Gorton #2. However the 1/8 inch pipe doesn’t have the size to handle both air and to be able to drain off any condensate (water) that gets near the vents.  While it would probably work at a short gap measure in the long run you’d want to go to a ½ pipe minimum.



When attaching vents to the steam main the important thing is to locate them so that any water reaching them will drain away.  If you have overhead clearance  mounting them on a long pipe nipple works well.  If you don’t have clearance using an antler works well. Orient the antler so that it is up slope from the vent hole in the main. This promotes drainage and slow down any water as it has to turn 180 degrees to reach the vent.



Multiple vents on one main should be okay. As mentioned before ideally the main vents should  be located just after the last radiator lateral on the main. Why vent all the rest of the piping?



Radiator Venting- I’m not sure whether there is much benefit in calculating the radiator volume as I haven’t found volume all that helpful. While it would seem that the faster you get the air out of the radiator the faster things would heat up this is always the case and sometimes using slower (lower capacity) vent actually speeds things up.  EDR is handy to know. I’ve attached a form on how to do calculate EDR.

You want to have lots of main venting capacity so your steam mains will be completely filled with steam before any reaches the radiators.  The last thing you want is the steam sequentially filling the radiators as it slowly moves down the steam main. This leads to “hogging” where the radiators closest to the boiler use all the steam and the smaller radiators farther down the line get very little. Here a link to info on venting I wrote up to answer a venting question some time back

which might be of help to you.

- Rod

Hi- You’re correct at low pressure a 1/8 pipe theoretically has the capacity to vent a Gorton #2. However the 1/8 inch pipe doesn’t have the size to handle both air and to be able to drain off any condensate (water) that gets near the vents.  While it would probably work at a short gap measure in the long run you’d want to go to a ½ pipe minimum.



When attaching vents to the steam main the important thing is to locate them so that any water reaching them will drain away.  If you have overhead clearance  mounting them on a long pipe nipple works well.  If you don’t have clearance using an antler works well. Orient the antler so that it is up slope from the vent hole in the main. This promotes drainage and slow down any water as it has to turn 180 degrees to reach the vent.



Multiple vents on one main should be okay. As mentioned before ideally the main vents should  be located just after the last radiator lateral on the main. Why vent all the rest of the piping?



Radiator Venting- I’m not sure whether there is much benefit in calculating the radiator volume as I haven’t found volume all that helpful. While it would seem that the faster you get the air out of the radiator the faster things would heat up this is always the case and sometimes using slower (lower capacity) vent actually speeds things up.  EDR is handy to know. I’ve attached a form on how to do calculate EDR.

You want to have lots of main venting capacity so your steam mains will be completely filled with steam before any reaches the radiators.  The last thing you want is the steam sequentially filling the radiators as it slowly moves down the steam main. This leads to “hogging” where the radiators closest to the boiler use all the steam and the smaller radiators farther down the line get very little. Here a link to info on venting I wrote up to answer a venting question some time back

which might be of help to you.

- Rod

 http://www.heatinghelp.com/files/posts/15362/System%20Venting%20-%20Radiators%20and%20Mains.pdf

Rod

The Venting Book

Hi-  While it is mentioned in one of the links I gave you I probably should also have included a direct reference to it in my previous post. Gerry Gill and Steve Pajek's book on venting is very useful and I use it constantly.  It’s available as a downloadable “e-book” from the Shop section this website. Here’s a link to it :

http://www.heatinghelp.com/products/Steam-Heating-Books/25/146/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-by-Gerry-Gill-and-Steve-Pajek

It shows you how to calculate the size of vent you need and has a lot of other info on vent sizes etc.  These tables are also included in Dan’s book, “ Greening Steam”.

- Rod