Piping / Venting Opinions

nz

Hello,



I'm a newbie on the site, but I'm learning quite a bit - thanks to all who have posted in the past so I can learn from you all.



I bought an 81 year old house about a year and a half ago. I've recently been reading quite a bit on how I can get the steam system working properly. I have 24 radiators (15 cast iron, 9 in-wall fin tube convectors). I'm currently in the process of measuring them all, so i can figure out the total EDR.



I have wet and dry returns, and 4 non-radiator traps. I believe these are called crossover traps, but I'm not certain. Three are Dunham 1Es, the fourth is a 2E. I have not found any vents on the steam mains (but they could be covered by plaster, the whole basement is.



My boiler is an natural gas fired American Standard Series: 3B J2. It has 7 burners. 525,000 BTU input, 420,000 output. The house is roughly 4,000 sq. ft. of space that is heated by steam - excluding a large room in the basement which has a gas fireplace, and the garage which is also heated.



I had the main vent replaced last year, because the old one was clogged and also whistled very loudly. That was before I found this site. I was talking to someone yesterday - they said that the vent that was installed was too small - it's a Hoffman Specialty No. 75, and that it was a vent for a steam main - not a main vent. I have attached a photo of it, and the related piping.



Also - the vent that was installed before had two pipes going into it. You can see from one of the pictures that a cap was installed on top of an elbow in the dry return.



Do you think this vent is too small for the system described? If so - I welcome your feedback.

BobC

how long and how big?

The hoffman 75 is rated to vent at the rate of 0.5CFM. You want to vent the steam mains quickly so it should be able to vent all the air in a couple of minutes.



To see if that vent can do the job we need to know haw long the steam main is and what size  the steam main pipe is. the attached chart should help with this.



Bob

crash2009

Dunham return trap?

Did the part they removed look like this?  The part removed to install the Hoffman 75.

nz

Mains

Bob -



The mains are as follows:



4.5" w/ insulation, so I presume they are 3 inch mains. The pipes coming out of the boiler are 3", and go into a single 4", and then split off onto the horizontal mains.



Left Main

27.5 feet (there are some horizontal 45 degree elbows as it snakes around.



Right Main

18 feet - then a T. One way it goes another 25 feet straight. The other way is a 7 foot, then an elbow, then another 4 feet, then a 45 degree, and then another 3-4 feet before the final riser.

nz

Vent

Crash -



The piping inputs looked similar. However the shape was different. I've been googling to find something similar, but haven't. I wish I had taken a picture before it was removed.



I found a diagram similar to what it might have been here - there was an air vent on top of it. My guess it was around 8-10" long, and about 6" tall.

http://constructionmanuals.tpub.com/14279/css/14279_89.htm



However, mine was connected via a loop rather than directly to the dry and wet returns.

BobC

too small?

My steam mains have 1" insulation on them and the outside circumference is 14 plus inches which translates to about 4" OD, my mains are 2" pipe. I don't know if your insulation is 1" or not but that Hoffman vent circumference is a bit smaller than a 2" pipe so maybe you can judge by that.



The long main is about 60 ft long. If it is 3" pipe that contains almost 3 cubic feet, if it is 2" pipe it has about 1.5 cubic feet. The short main would have about half that volume of air in it. If that one vent is trying to vent the air from both mains it is undersized. You would like to vent the air in a couple of minutes so steam can fill the mains and start up the leaders to the radiators.



From a cold start how long does it take that air vent to get hot? Try timing the amount of time it takes that vent to get hot (or very warm) from the time the boiler riser gets hot. I don't have a clear picture of that vents relation to the two mains so that number would be useful.



A Gorton #2 will vent air at 1.1 CFM vs the Hoffman 75's 0.5 CFM. My systems a lot smaller than yours, it has about 15 ft of 2" main and a Gorton #1 (0.3 CFM) and that Gorton gets hot 2 minutes after the boiler outlet gets hot.



Bob

crash2009

Dunham System

Sounds like you have some type of Dunham System.  Whomever removed the whatever kind of trap that was, was not looking out for your best interest.  There is quite a bit of information up in the library here on the subject of Dunham.  Maybe you could spot your system there.  Could we see a picture of one of the radiators?  and Maybe a closeup of the shutoff and or adjustment valve on the radiator? 

nz

Venting time

The main vent never gets hot, unless I crank up the pressure and turn up the thermostat by about 4 degrees.



There are no vents on the end of the mains...the return lines have crossover traps. It is my understanding that they vent the air into the returns until steam hits them.



It takes over 20 minutes from a cold start for the radiators to start warming up, but it has to run much longer to warm up the "cold" side of the house. Right now I have the pressuretrol set to 1psi cut in + 1psi cutout, so it cuts off at about 2psi. I had it set to 1.5psi cutout (i know the lower the better) - but my feeling is that I'm not venting nearly enough, so I have to compensate for that.



Should I just remove the vent and see if it performs better? Or is that a big no-no?

nz

Radiator Pics

Here they are. Several of these valves have been replaced due to leaking over time. Most of the traps are intact.

crash2009

Air Eliminator?

Wow, fantastic place you have there.  I was just up in the library looking at some Dunham piping diagrams  http://www.heatinghelp.com/files/articles/1298/bulletin%20628%20-%20pages%20vertical.pdf  page 29, near as I can figure out, it looks like they removed your air eliminator.  Of course, I don't know for sure, but thats what it looks like to me.  Have you met Steamhead yet?  This type of system is right up his alley.  He just loves these old, quality, systems.   What part of the country are you located? 

crash2009

perfect pictures

Somebody that knows something about these things should be right with you.  It has been kinda quiet around here today though.  Maybe later.

nz

Air Eliminator

I found this here...

http://www.heatinghelp.com/files/articles/1821/dunham.pdf



Page 12, Figure 1585 - the "Air Eliminator with Air Check" IS what was removed. It had that little vent on top of it, same shape and everything.



However - there was never a Dunham Return trap piped into the system for as long as I've owned the house (1.5 years) - so there were 80 years before I owned the home for someone to remove it.



I'm just north of Detroit - in the Grosse Pointe area.

crash2009

Neighbor

You are dam near my neighbor.  I am in Ann Arbor.  Tough to find an old school steam man around here. 

crash2009

Is it running good enough

 to get you through the winter?  If you are looking for a quick fix, hire one of the big names here for consulting, then straighten it out in the spring.

nz

Found it

Yeah, you are pretty close Haven't found anyone good around this area.



This looks like darn-close to the original piping of the vent.

http://www.heatinghelp.com/files/articles/1349/313.pdf



First page (page 61) - figure 860D (bottom right)



So now that it is gone, and I have (presumably) an undersized vent...should I set up an array of Gorton No. 2s?

nz

Winter

It got me through last winter, and I'm sure it will this winter too. However I've just recently found this site and started looking into why my system is running inefficiently (bad traps, leaking radiator supply valves, some mild water hammer, radiators that don't fill up before the boiler shuts off, etc.)



When I moved in, the gas regulator was on full blast, and the pressuretrol was set to something ridiculous like 10 psi. The water hammers were very obnoxious, and setting back the gas regulator and replacing the failed air eliminator with the vent (although it may be undersized) helped remove the massive water hammer in one section of the house.

nz

Mains Diagram

Here is a diagram w/ measurements of the lengths of my horizontal mains. There is a section of the house that is not under these mains, it looks like there is a branch off the main at a 45 degree angle that goes up into a ceiling of another room of the basement... and then presumably runs nearly horizontal for another 20 or 30 feet (since there are 6 or so radiators in that area.)

moneypitfeeder

you're in the right place

You have all best people on this forum to help you. One thing that took me awhile to get, was that even if my system were optimized, that unless it was the coldest day on record, some of my (larger)  radiators will never get hot all the way across. The amount of steam being produced to satisfy the thermostat is not enough to fill the entire rad because its just not that cold out. It seems to be an oddity, because if your used to furnaces,  each vent blows hot air from one side of it to the other, but with steam, it only sends enough till the room the thermostat is in is satisfied then shuts off, so some rads might be hot all the way across, some only halfway. As far as I have been able to tell the best way to try to start to balance the system is making the steam get to each radiator at about the same time. (whether it gets hot all the way across or not is not necessarily important unless the rad has a blockage of some sort) Welcome aboard

nz

Thank you

Thanks - I hope to learn from all of you.



Some of my radiators don't get even warm, unless I run it up to 5psi. That's where most of my problems lie (high pressure = bad for efficiency, speed of steam etc.) I would like to run on ounces, but I'm not able to at this point since half the house won't heat up (like 45-50 degrees in some parts) before the thermostat or pressuretrol cuts out.



I have a Dunham 2E in the garage, which the rooms above the garage are usually cold if I don't have the pressuretrol set to 5psi. Both sides of the trap are hot (210-214 F according to my Fluke infrared thermometer) when the steam has been going for about 10-15 minutes. It seems to connect part of a main and a return line, perhaps this is a drip trap? I get a mild water hammer in this part of the house. I have a feeling this trap might be stuck open.

Long Beach Ed

Balance

You're on the mark about steam distribution and system balance.  More important though is that each room heats evenly.  When that system was designed, each radiator was sized to the heat loss of its room.  Since then, some rooms may have been insulated, new windows installed, walls opened up. 



Generally, though a well balanced system will feed steam to each radiator at about the same time, if that's what you want. 



The Dunham systems were very nice because each radiator could be adjusted to offer more or less heat.  



Don't cry too many tears over the missing Air Eliminator.  While we hate to see great old cast iron go to the dump, today you can regulate steam pressures rather precisely making that whole float arrangement unnecessary and easily replaced by a regular vent or vents.   Unfortunately, for the thing to work properly, the pressure has to be kept low. 



Let's see if someone offers you a few easy ways to check those traps and some less easy ways to change the bad ones.

crash2009

While we are waiting

I say we, because I want to know the solution also.  Perhaps I could refer you to The Best Heating System   http://www.heatinghelp.com/forum-thread/131216/The-Best-Heating-System  This is Dave's house and he has been working on it for awhile now.  Included in the thread are his experience rebuilding various Dunham components, such as the #2 rad trap and the 1-E.  I am sure you will feel right at home.

Steamhead

You have a "Dunham Home Heating System"

which is described in chapter 15 of Dan's excellent book "The Lost Art of Steam Heating"- page 252.



This is a pretty standard Vapor system. The crossover traps act as the main vents, routing air from the steam mains into the dry (overhead) returns. From there, it traveled to the boiler room, where the Float Trap/Air Eliminator (the device that was removed) was mounted. The air from the radiators also passed thru the dry returns this way.



The FT/AE was the only place in the system where air could leave. It had a little check valve in the top, so the system could go into vacuum as the coal burned down. This was a great feature when burning coal, but it doesn't work well on oil or gas with their much shorter firing cycles.



Since this is the only vent point in the entire system, you need a much bigger vent. I'd start with a Gorton #2 and see how that works- if it's still sluggish, add a second #2. The #2 has roughly four times the capacity of the Hoffman #75. It was designed as a Vapor system vent, but today we use it for other types of steam systems too.



The #2E in the pic is being used as a drip trap which also vents that steam main. This trap, and the several crossover traps, get more of a workout than the radiator traps since they operate every cycle, even on mild days when the rad traps don't see steam. Fix these traps first.



The Dunham company still exists, under the name Marshalltown Engineered Products Co. (MEPCO). I believe you can still get trap parts from them, and maybe valve parts too. If not, Tunstall Corp. can supply rebuilding kits for traps and valves.

nz

Thank you

Thank you Steamhead. I will buy a Gorton #2 and see how that works. Should I put it exactly where the main vent is now?



If I need a second - how would you recommend laying them out? Put a tee on and extend it to the right?



I bought Dan's books on Thursday, but I haven't received them yet. I will check out that section first when they arrive.



I did purchase a MEPCO 1E retrofit cartridge a few weeks ago, but I have having some trouble getting the radiator caps off (without destroying them). I will be buying their radiator cap wrench, hopefully that, with some PB will let me take them off.



Again - many thanks!

moneypitfeeder

yep...

If both sides of the trap are "steam hot" then the trap is either toast, or the pressure is too high not allowing it to work and holding it open.

Dave in QCA

ooooops

I had just typed several paragraphs, then lost it by clicking on one of your pictures and couldn't get back.   (%^(%*)()&(!!!    I don't have the time at the moment to retype everything, but will post that there are some trap repair caps on ebay at   http://www.ebay.com/itm/Dunham-Bush-1E-steam-trap-cap-disc-/230703677045?pt=LH_DefaultDomain_0&hash=item35b702be75   



I have kept my own dunham supplies stocked up from watching here, and have had good luck.

nz

Good Idea

Dave - sorry I missed out on all of your post...oh well.



Never thought of eBay for steam stuff. I'm actually an IT guy for a career, so I'm quite used to going there for computer stuff.



Have you found it better to do the following:



1. Replace the disc & cap and keep the original trap body?

2. Install the MEPCO retrofit cartridge onto the original trap body?

3. Replace the whole trap body?

4. Just replace the disk, keeping the original disk and body?



The cap and disc seem the most economical, but I'm concerned about how dirty the trap seat will be - and since I haven't done this yet...I don't have any experience to know what I should expect.

Dave in QCA

Dunham air eliminator, traps, etc.

The device that was tossed out, as you know was the Dunham Air Eliminator.  This device consisted of an open vent port and a float valve that would close if the water level got to high in the returns, to prevent spilling condensate out through the otherwise open vent.  The device was usually fitted with an Air Check, that would let air out, but not let it back in.  This allowed the system to go into a self induced vacuum.  While Dunham indicated that its vapor and vacuum operation was beneficial in gas and oil fired boilers as well as coal, Hoffman Specialty gives instructions that its #76 Vacuum Vent is to be used only on coal firing, and if a system is converted to gas or oil, that a #75 vent, which does not have a vacuum check, should be used as a replacement.  So, it seems to me that the common practice and belief today, that vacuum should never be allowed on a gas or oil steam system originates from Hoffman Specialty's instruction, and this is contrary to Dunham information.    Perhaps this year I will get some re-piping done that will allow me to operate in vacuum, and I will be able to report on my experience.



So, since the Dunham Air Eliminator was an open vent that did not close with the presence of steam, theoretically you could vent with an open pipe as long as you keep your pressures low.  Remember, 1 psi at the boiler = 30" water column above the water line.  That is to say, if you have a pressure of 1 psi, it will take a 30" water column in your return pipe before there is enough weight to push water into the boiler.  So, you could measure the distance between your water line and the horizontal return piping and see where you are.  Also, between the 2 connections where your Air Eliminator was connected.  It might be a good idea to install a vapor stat, that will allow you to more precisely limit your boiler pressure to lower pressures, such as 8 oz.  That really is all the pressure your system will need and it will work quite nicely at those low pressures.   If you decide to use one or two Gorton #2 vents, you will have extra protection for your system.  They have a float that will close if the water backs up, and also will close with the presence of heat, 130-150F, so if you had a trap fail open, the Gorton would close to prevent steam from escaping into your basement.



The Dunham traps are a good design and they pass a lot of air, about the same as a Gorton #2.  However, if you repair them with a cage unit, such as Barnes and Jones, their venting capacity will be reduced.  I have found Dunham traps to be very reliable and have a long life, so I would recommend replacing with Dunham parts, either the new cap with disc, or replace the disc in the existing cap.  For me, it depends on what I can find at a good price, usually on eBay.  

 

The Dunham traps used as crossovers provide great venting of the mains, and this is essential to get steam to the ends of the main quickly which is necessary to provide for even steam distribution.  However, the crossover trap must close when steam gets there, otherwise you will probably get water hammer and possible enough steam in your return lines to inhibit the flow of steam to the radiators connected to the same return line.



A word about substitution other traps... DON"T DO IT.   This comes from experience.   The Dunham trap has a very large port and vents very well as mentioned before.  Many other traps, such as the Hoffman 17C have a much lower venting rate, and if you use these, they will throw the system out of balance.  Also, the actual dimensions of the traps vary, so the best thing is to simply repair your existing traps, and if you have to, replace with a new Mepco or New old stock Dunham-Bush trap.  They also come up on eBay from time to time.



Once you get your cross over traps corrected, then start checking out your radiators for ones that simply do not heat.  It can safely be assumed that those radiators have traps that have failed.   But, before I go on, it would be a good idea to double check those slow radiators to make sure that there are not orifices in the valves.  They would be in the outlet of the valve, at the union connection.  It is possible that your system had orifices at all radiators and if someone took half of them out, it would cause the rads with orifice still remaining to barely heat at all.  Just worth double checking... again, this was learned by experience.



To open up an old trap, I usually back up the trap with a large pipe wrench, and use a very large crescent wrench on the cap.  If you have a cap tool, that would be even better.   Some good solid tapping with a hammer around the perimeter of the top surface of the cap is useful too.  If it is stubborn, I usually heat it up with a propane torch, but don't do this unless you are pretty certain the disc has failed, because the heat may be enough to melt the solder joints in the disc, and so it will definitely be bad when you open it up.  For failed worn out discs, you will usually find cracks in the metal of the disc element. 



Which pipe to use for your vent?  Well, actually both would be best.  It is advantageous to have the vent as high as possible, that is, at or above the upper connection.  But it is only a 1/2" line and you might get better venting off the lower 3/4" connection, but if you have pressures that cause the water to back up to that point, it would be beneficial to still be connected to the upper pipe.   You could create a loop between them and then run a branch off the side , from which you would install your vents.  On the other hand, you probably will not need more than one or two Gorton #2 vents, and an open 1/2" pipe vents the same as 2 Gorton #2 vents, so you should be fine using the upper pipe.  



Did your service man cap off another pipe too?  Usually, Dunham systems had an equalizer pipe running between the steam and the return piping, and it was usually connected to the piping for the Air Eliminator and/or Return Trap if it was present.  This equalizer line also had a swing check in it that allowed air to pass from the return line to the steam main.  The purpose to allow the the strong vacuum which occurs first in the steam mains when the boiler shuts down, to draw any remaining air from the return side, and thus assure that the vacuum in the steam side never exceeds that of the return side.  This, in turn, prevents the hanging up of condensate in the returns as a result of the vacuum in the steam side is being relieved by back flow in all of the returns, traps, and radiators. 



If you do not use a check valve on your venting, and thus do not use vacuum, this equalizer will allow a faster relief of the vacuum in your steam piping without interfering with the proper flow of condensate.  If you can see a capped steam pipe in the immediate vicinity of your old Air Eliminator, that would be where it was connected.



Sorry for being so windy, but I can take any short story and make it long... and I usually do.

crash2009

Wow

You guys are the greatest.  I think it's working better all-ready!  Thanks for the education.

nz

You Rock

Dave - thank you. Lots of great info.



I have not found another pipe near the boiler that was capped off (yet).



I have a 24" adjustable wrench on my xmas list



I took off that Hoffman No75 vent- seems to be working ok with an open pipe (no steam or water). I ordered a Gorton #2 to replace it with. The system seems to be running about 0.05PSI lower (0.2PSI max now). I'm convinced that 2E drip/vent trap in the garage is bad, one of the radiators in the garage doesn't even get hot. I will order a new cap & disk for it.



The second radiator in the garage has a leak in it, so I have its valve off. I guess it was disconnected for a reason...lol. I had the heating guy hook it back up last year - he put a Hoffman 17c on it. So once I get that leak fixed with some JB Weld, I'll buy a Mepco trap and change it out.

nz

New Vent

OK - got my Gorton #2 in the mail today from one of the common online retailers. Oddly enough, it seemed like it might have been used - some of the paint was rubbed off (although this could have been packaging), a drop of water dripped out onto my desk @ work as I took it out of the box, and it seemed like there was some pipe dope inside the opening.



Either way, I put it on tonight. It seems to be working properly, although I couldn't hear anything when the system goes into vacuum (I could hear it before with the Hoffman #75). See attached pics for before and after. I do plan to add a second G2 in a few weeks.



My PSI still won't get above 0.2 PSI most times....(most I ever saw it at was 0.25PSI, or 4 OZ - and that was running the boiler for an hour straight). Thought the snubber might have been throwing off the gauge (0-3 PSI Wika) - so I took it off but the reading is the same. I'm pretty sure I have some leaky radiator valves, so the pressuretrol never kicks in.



I wouldn't consider this a problem, except a good portion of the radiators never get hot or only part hot, even steaming for an hour. I bought some replacement trap discs on ebay, I will replace these on the drip and return traps in the next few weeks.

crash2009

Missing part, or newer style

Is that some new style of G2?  Where is the vent hole?  On all mine there is a little protrusion that sticks out the top of the vent.  Another thing you want to do before you install it is a blow test.  Test it right side up and upside down.



edit:  Might just be the picture angle, after closer inspection, I do see something on top of the vent.



oh yea, go get a wet rag and wipe the pipe dope off those threads, before Ed see's it.

Long Beach Ed

Too late

...I 'seen it already.

Dave in QCA

low pressure is good

The fact that your pressure does not rise above 4 oz indicates that your boiler is very closely matched to the connected EDR.  This is a good thing.  Of course, when you get the bad traps fixed, you will have more load, but I think you will be fine.  I am confident that the trap repairs will get heat into those cold radiators and you're going to be in fine shape!

nz

Vent

Yeah, there is a nub on top with four holes, like yours. It was just a crappy angle.



I'll make sure to clean up that pipe dope for LBE

Steamhead

I believe they test at least some of those vents

before sending them out. That would account for the dope and the little bit of water. 

malex

Coincidence

I ordered a Gorton #2 as well from probably the same online retailer and it too had some scratches on the body. Are they trying to get rid of a batch of returned vents (and maybe defectve)? It past the blow test (lets through air upright but is shut upside down). I am still suspicious of its functioning. While my G#1 on the short main is noticeably pushing air i don't hear a peep from the #2 and I don't feel air coming out of it like the #1. Could this be because of the larger hole making the velocity lesser? Also, when boiler shuts down I am suspecting that it is slow to open as it is usually still hot so I get some vacuum and sucking from the radiator vents.



I am considering adding Hoffman's on both mains to be on safe side.

Dave in QCA

Fast to close, Late to open

My experience is that my G2 is very fast to close and very slow to open.  I think this is the norm for them.



It will have little or no effect on Nzeigler's system however, as his G2 will never see steam except in the rare event that one of his Dunham traps fails in the open position.

MotownSteamer

Welcome neighbor!

Hi, welcome to the site! I live in the Park. There are a few steam geek homeowners around here, and a couple of old school contractors that know what they are doing.



I have a Trane 2-pipe vapor system. My radiators all had Dunham traps. I had the same trouble popping the caps off to get at the trap elements. Long story short, I ended up replacing all the trap bodies with new Mepco replacements. They were cheaper than the repair kits! It was a hefty job, and not a winter project, but my system hums. I also replaced the cross over traps. I think your #2 main vent will be fine. I have a Barnes and Jones quick vent and it works like a champ.



You have twice the # of radiators I did so if you want some help replacing traps we can exchange contact info and work on it in the spring.



Like others have said, don't worry about the missing return trap/air eliminator, etc. My original Trane Direct return trap is still piped into the system, but will likely never see action because we run at such low pressures. I think all that stuff was designed for coal fires when pressure was difficult to regulate and balance.



Anyway, thanks for learning your system and keeping this stuff alive. I almost cry when I see radiators on the curb because someone got talked into gutting it out and putting in a forced air furnace!



Scott