Two-Pipe Vapor - Dunham Home Heating System

gerry gill

vent the return main heavily, then rebuild the traps on the radiators with air vents first, then remove those air vents from the radiators,and see if they then heat without the air vents on them.

TonyBal_2

Two Pipe Vapor - Dunham Home Heating System

Steam - Two Pipe Vapor System. Circa 1929 --- Dunham Home Heating System

This inquiry is about my steam home heating system. The system was installed about 1929 and I have lived in the home since 2002. Considering its age, the system has worked rather well, but the heating costs have been VERY HIGH. I realize the system is not efficient by today’s standards, but I think it can be improved. (I am not yet ready to convert to hot water or a new steam furnace.)

It’s taken me six years to figure this out, but I think my system is similar to the Dunham Home Heating System pictured on page 252 of Dan Holohan’s “The Lost Art of Steam Heating” (1992). A two pipe
low pressure vapor system.

Radiators (17) – American Radiator. Two Pipe. Top supply feed. Radiator Traps – Jas Marsh No. 1 Reflux.

Boiler – American Radiator Corp. Converted to oil burner, and then in 2002 to a gas burner.

Fuel – Wayne Power Gas Conversion Burner new in 2002

Although this is a two pipe system, the radiators in the dining room and living room were fitted (prior to my purchase of the home) with single pipe air valves (Little Wonder Air Valve No. A-880). These units hiss and let you know when the steam is coming on. My guess is that in the distant past the heating system was not working and rather than paying for trap finding/replacement/repair, a previous homeowner opted for putting air valves on several radiators. Holohan talks about the many problems associated with this. Or there could have been another problem I have not considered.

The system has a Dunham Air Eliminator (220B). I do not recall ever hearing this unit discharge air from its top vent.

The system has no Boiler Return Trap. Dan Holohan says that a Boiler Return Trap was not needed on this system because of the large Damper Regulator. Pressure “never went above eight ounces.” A McDonnell Boiler Control No. 47 has replaced the original Damper Regulator.

Four Suspect Traps

In the basement directly above the boiler there are three “crossover vent/traps” (Dunham Air Line Valves, or Dunham No. 1 Traps??) at higher points than Dunham Air Eliminator “perched on top” of three dry returns. These three traps look like MEPCO (formerly Dunham-Bush) 1E Angle Pattern traps. These traps look like Holohan’s photo (figure13) on page 238 of his book. These do not look like they have been serviced in a long time if ever.

There is also at least one more thermostatic trap above dry returns further away from boiler (about 20 feet). Illinois Engineering Corp “Thermo” No. 1. This trap hard to access and I doubt it has been serviced. This trap is close to (below) living room radiators where I hear some mild hammer. This trap does not look like it has been serviced in a long time if ever.

My thought is to go slow but to:

Replace four above mentioned vent/traps. (These four traps may or may not have repair cartridges for them).
Replace bonnet/diaphragms the traps in most or all radiators. Repair cartridges are available for Marsh Reflux No.1
Determine if the Dunham Air Eliminator is working properly.
Have a pro help with most of this. Perhaps I can replace the Marsh Reflux traps over time.

The goal is to get the two-pipe system to work correctly so I can remove the single pipe “Little Wonder” air valves. I am trying to get my heating bill down by getting the system back close to original two-pipe design intent.

I would appreciate any thoughts. I don’t know much about this stuff. Am I looking at this in the right way?

Thanks GN – Homeowner

Paul Fredricks_9

It sure looks like you've done your homework. It also sounds like you're on the right track. There are many here that know more than I do and I'm sure they'll let you know if your solutions are the right way to go.

And pictures, we'd love to see pictures of your system.

gerry gill

your on the right track,

all the traps should probably be rebuilt..my gut feeling is that the original main air vent isn't venting at nearly enough cubic feet per minute for an on/off firing boiler..and it sounds like you are still using a coal boiler to heat with..doesn't matter that its got a conversion burner..its still a coal boiler with mongo thick iron to heat through..probably would be wise to consider an upgrade..

TonyBal_2

Photos - Two Pipe Vapor Dunham

TonyBal_2

TonyBal_2

Photos Attached - Two Pipe Vapor - Dunham Home Heating System

This is an add-on note to my earlier longer message above.

Thank you for the comments. I have tried to attach photos of my boiler.

The plan when we bought the house in 2002 was to put in a new Burham Steam Boiler, but we got cold feet about having it done right. (and there are not as many good steam guys out West...Let me know if you know of one in Oregon).

The more I read Dan's book re problems w/conversion of these Vapor systems the more nervous I got/get. One of the older pros asked me why I would want a new Boiler if the old one did not leak? I did not have a great answer.

So here it is. My "cast-iron ham." If we can get above mentioned (trap/vent??)problems fixed then maybe we will be ready for a new boiler but first get the two pipe system working as it was designed.

We had the white suits come in and rip off the asbestos and had commercial guys put on new insulation.

There is an old water heater still attached (Excelso Products Corp) that has had the tank removed a long time ago.

I put pink tags near the three traps yesterday near the ceiling just to help me keep track of things. Those are the 3 traps above boiler that I think may be broken (see last message).

The hidden trap is farther out from the boiler but I bet this trap is broken also as it is very hard to find. Been remodeled over. As I said I am getting some mild hammer above this trap I think.

Would the Dunham Air eliminator not work after someone put vents on several raditors upstairs? I assume that is why it is not blowing air out the top. But maybe it is broken also.

Oh, and all 17 radiators likely need new Marsh trap parts. I think I may be able to do this piece myself. Maybe a couple per week in the winter and note any major hammer or heat changes as I go.

I ramble.

Any thoughts on this or my previous message today appreciated.

Thanks!

GN - Homeowner

Steamhead (in transit)

The float in that Dunham air eliminator

is probably stuck shut. This would kill any chance for air to get out of that system. If the air can't get out, the steam can't get in.

If you can get an impact driver on those bolts, you stand a decent chance of getting it apart. If that doesn't work, you can simply replace that air eliminator with a couple of Gorton #2 vents.

I wouldn't work on the traps until you're certain the air can vent.

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gerry gill_2

wow, nice boiler room.

looks like your boiler room is clean enough to eat in..my compliments.

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Jim Bennett

Thoughts...

Very nice insulation job!

If you attempt to rebuild the traps yourself, consider doing it off season so you are not "under the gun" if something doesn't go quite right.

Getting the caps off 80 year old traps can sometimes be a challenge.

As Paul said, you have done a great job doing your homework. You know more about your heating system than most homeowners in America.

Also, what pressure is the system running. Vapor systems running higher pressure will waste fuel.

Good luck,

Jim

nicholas bonham-carter

vapor system

while you are at it, check your pressure, which if too high, may have caused the demise of the traps. a vaporstat and a good low pressure gauge[gaugestore.com 0-15 oz.] will tell you if you are down in the 3-8 oz. range.--nbc

Jamie Hall

You're definetly on the right track

but do heed Steamhead's comments -- and make sure that you have good main venting before you do anything else. Then, as he says, start to worry about traps. Traps fail in two ways: stuck shut or stuck open. Stuck shut (particularly those crossover traps) and you'll get no heat or very little or slow heat in the affected areas; stuck open and you may get no heat at all! You can find a stuck open trap fairly easily, though -- the return after the trap can be warm, even rather hot, but not to the ouch! point.

Also, pressure is critical on these systems -- the good news is that if you don't have a vapourstat, you can get one and install it on your existing boiler (use a new, preferably red brass, pigtail) -- and then, when you do get that new boiler (which will drop your heating bill dramatically) you already have the vapourstat, ready to install.

Vapour steam systems, like yours, are very economical, once you get them set up right -- which isn't all that hard. When you do put a new boiler in, you should see significant savings (just be darn sure that when you put it in, it gets piped properly! and that the water line is no lower than, and not much higher than, the existing water line!!).

TonyBal_2

Two Pipe Vapor - More Photos, More Qs. This guy won't go away...

Thank you for all the responses! This site is awesome. I am learning so much.

Main Venting
“Make sure that you have good main venting.” Just so I am clear. This is the purpose of the Dunham Air Eliminator in the original set-up and why it must be checked out. There was no other way for air to exit the system in 1929.

Dunham Air Eliminator issues:
Dunham Air Eliminator capacity. Mine is the model 220B. With Capacity Sq Ft EDR of 2000. Their bigger model (the 221, apparently discontinued) has Capacity of 6000 EDR. This is all Greek to me, but perhaps original owner should have gone w/larger model as this boiler is feeding 17 radiators. I will have my 220B checked out. It sounds like a good possibility that the Dunham 220B is now broken, or it was undersized to begin with.

Gorton #2 Vent Alternative to Dunham Air Eliminator
Will the Gorton #2 also shut off its vent if water rises into it, thus keeping water from escaping, and won’t let air in, etc.??

Four Suspect Traps Question
The four (crossover) traps near my basement ceiling: Is it possible to replace these with another brand of trap that will serve same purpose if we have trouble identifying or repairing the exact original trap?? Some repeated detail below.

Four Suspect Traps
In the basement directly above the boiler there are three “crossover vent/traps” (Dunham Air Line Valves, or Dunham No. 1 Traps??) at higher points than Dunham Air Eliminator “perched on top” of three dry returns. These three traps look like MEPCO (formerly Dunham-Bush) 1E Angle Pattern traps. These traps look like Holohan’s photo (figure13) on page 238 of his book. There is also at least one more thermostatic trap above dry returns further away from boiler (about 20 feet). Illinois Engineering Corp “Thermo” No. 1. This trap hard to access and I doubt it has been serviced. This trap is close to (below) living room radiators where I hear some mild hammer.

Pressure Gauge
I have included a photo of my gauge. I think it is one of the cooler things on my unit, but I have wondered why it never seemed to deviate much from zero. It would appear a model with lower sensitivity would be better?? I will look at gaugestore.com for 0-15oz.

Honeywell Vaporstat
I have included a photo. It seems to be set to very low pressure as one would expect. But it looks like it is measured to pounds instead of ounces. Wonder if this unit too is not sensitive enough, though seems to work OK. I found another one on the net: HONEYWELL L408J1025 0-16oz. VAPORSTAT. Better way to go??

My Radiators
I have included photos of two of them along with the small vents on the side of each. They are two pipe units, but have an air vent (silver color) placed on them. This was done just on four radiators in the home. The other 13 do not have vents and heat OK, though I expect they would heat even better with new trap components.

Radiator Painting
I have tried a bit of this and gone w/high temp auto engine enamel on one radiator. Seemed to work out OK. Please let me know if there is a recommended approach to painting them. I have more painting to do…

Contributions
If OK with DH, I’ll be cutting a nominal check to his co. to contribute to one of his get-togethers or programs. My Qs seem to growing the more you feed me and I am no freeloader.

Thanks Again. I appreciate any comments re above Qs.

GN - Homeowner

Steamhead (in transit)

Answers

Main Venting- this is the job of those crossover traps. They route the air from the steam main into the dry return, and it leaves the dry return thru the Air Eliminator. I'd look at the air eliminator first, as it is the one point that must work for air to exit any part of the system. The air eliminator itself should already be sized properly- 6000 square feet EDR is the radiation in a 32-unit apartment building we service. If there is a vacuum check in the cap on top of the air Eliminator, remove it (but don't trash it, in case you ever want to use a solid-fuel boiler with that system) as vacuum doesn't work well on oil or gas firing.

The Gorton #2 vents will close against water. No problems there.

The MEPCO crossover traps are new enough that they should be OK. Does the Illinois trap you mention serve as a trap to a radiator on the floor above?

I'd leave that gauge there and add a low-pressure one (0-20 ounces or so) to it. Technically, you need at least one gauge that can read twice the boiler's (NOT the system's) highest allowable working pressure to meet Code. Your present gauge can't read up to 30 pounds (twice the max working pressure of 15 pounds on that boiler) but I don't see a need to change it unless an inspector makes you do so.

The pressure control is a Pressuretrol, not a Vaporstat. It's calibrated in pounds rather than ounces. Currently it's cranked down as far as it will go. I'd change it to a Vaporstat, and a brass pigtail that won't rust shut.

Make sure the air can vent properly from the system as discussed above, then remove the radiator vents and put 1/8" pipe plugs in their holes. If the rads stop heating without the vents, you probably need new trap elements.

High temp auto paint should be fine.

Where is this system located?



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TonyBal_2

reply

I'm pretty sure the Illinois trap (hidden trap photo earlier) is a crossover trap (geez listen to me, like I know what I'm talking about...). It is between two pipes that look like condensate pipes. It is further away from the other three crossover traps though (they are directly above the boiler). The Illinois crossover trap is about 20 feet from the boiler and closer to area that is below a couple of massive livingroom radiators (one in picture earlier). It's also near a ceiling radiator in basement rec room and near ceiling radiator in guest room in basement. Also near guest bath that had a ceiling radiator but it was removed in the 80s. All rads have traps.

I am located in Portland, Oregon.

So far my to do list is not that bad:

Here is what i came up with:

Q: Why were air valves installed on four (two-pipe) radiators upstairs?

Possibilities?

1. The original Dunham Air Eliminator 220B (2000 EDR) was undersized.

2. The Dunham Air Eliminator is broken. (stuck shut?)

3. Some or all of the four basement vapor system “crossover” traps are broken (pg 238 of Holohan’s “Lost Art”)

4. Some or all of the 17 radiator thermostatic traps are broken


To do:


(1) Improve Instruments for Low Pressure vapor system

Add new Vaporstat and new Low Pressure Gauge mounted on tee above brass pigtail.

• Remove old Honeywell Pressuretrol. Add Honeywell VaporStat. L408J ?

• Add Low Pressure Gauge (0-15 oz.)

• Leave old Jas Marsh pressure gauge unit on boiler.


(2) Evaluate Dunham Air Eliminator


(3) Replace four basement “crossover” traps


Thanks so much. I have ordered a book from Ebay..."Dunham HandBook Heating System Engineering History 1935" It may have some fun info in it. We'll see.

Any comments appreciated!

GN Homeowner.

Steamhead (in transit)

Air Venting is the first priority

if you find problems there, fixing them might mean you find other system components are OK.

The Dunham name didn't change to MEPCO until fairly recently. So if you have traps labeled MEPCO, they're fairly new and likely (though not definitely) won't require service.

We've run info lots of Vapor systems where traps were replaced on radiators that wouldn't heat- and they still didn't heat. The problems were elsewhere. So make sure- 1. that the air can vent freely, 2- that the crossover and radiator traps haven't failed in the closed position, and 3- that steam isn't getting into the dry return from a bad trap that has failed open. You can tell the latter just by feeling the dry return around the return connection from the trap. It should get a bit warm, from warm condensate, but never steam-hot.

On a Dunham system, steam in the dry return is a no-no. It kills the slight pressure differential between the steam and return sides of the system, so steam cannot flow. Also the dry returns are too small to handle steam, so banging may result if steam gets in them. And a failed-open trap may cause radiators elsewhere in the system to not heat. So if you find any traps leaking steam into the dry return, fix them.

I think your Dunham handbook is the #514. I have that book, as do many others here on the Wall. You'll find lots of useful info there.

I wonder if the part of your system with Illinois traps was added later?

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TonyBal_2

MEPCO

My bad re MEPCO. because I have a Dunham Air Eliminator I looked at the crossover traps (on web) and noticed my traps look very much like Dunham Bush (now MEPCO) traps 1E or 1ESS. Though my crossover traps do not have any markings on the tops from what I can tell. Reason I wonder if i have to get the manuf exactly right when I replace them. I am leaning to replace the entire trap rather than an insert. I think my traps are vintage 1929. I could be wrong though. sorry to be confusing. Photo of trap attached (this photo shows 2 of the 3, one in far lower right. dusty area.)

The Illinois trap may have been added later as it is in an area that was remodeled many decades ago. They may have put on a new trap before the sheetrocked over it. I doubt they did any new rad work though. I can only see it by looking inside a cupboard and pushing out false ceiling. nice. i plan to demo small sheetrock section and put in small door. my plan anyway. if I have this trap right it looks like similar to B&J cage unit #1930. Trying to see what kind of trap will replace a 1/2" Illinois Thermo No 1.

I took some blind photos this morning inside tough to see areas that were sheetrocked and it seems this is my only "hidden" crossover trap. I hope.

You guys are awesome. I'll be donating some bricks...

GN - Homeowner.

Steamhead (in transit)

If you do completely replace the crossover traps

the Barnes & Jones #122 has a decent throughput for air venting purposes.

Since someone painted those traps, they may have covered the model info which is on the top of the cap.

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Jim Bennett

Those traps....

do look like Dunham 1E's If they are in an inaccessible location then replacing the trap may be easier than removing the covers.

Jim

TonyBal_2

Frank was correct, the float was frozen shut

No air getting in at all. could have led to vents on rads no doubt. see photo.

One less question to answer.

System still seems a bit under-vented and looking for ideas re Gorton #2s placement.

Thanks!

GN Homeowner

Steamhead (in transit)

First

add one or two near the original air eliminator. Even after you unstick the float, it still only has so much venting capacity. Then make sure your crossover traps work and fix the water pocket at the old Illinois trap, and see where that takes you.

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