restoring crossover traps - want advice

b_bz

I have a 2-pipe, vapor, Dunham Home Heating System. The two primary steam mains have no venting. I believe someone removed two end-of-main, crossover traps that used to provide a path to the dry return and Air Eliminator. I want to create a new crossover trap piping arrangement.

My system has one large pipe that rises through the basement ceiling toward the ceiling of the first floor. Just below the 1st floor ceiling, a branch heads to the back, then, one branch heads to the south side while another one heads north. Both branches then turn 90 degrees and travel in parallel east, along the outer edges of the 1st floor ceiling to the front of the building where each drops down to the basement. There is some evidence of missing crossover traps in the basement where each main comes through the ceiling.

I have been unable to interest any professionals in this project so I am left on my own to engineer pipes, fittings etc.. I’m a retired electronic technician and plumbing is a new, still foreign, language. My husband and brother will help get parts and turn wrenches but I must lead. If I’m way off-base on this, they will not help again.

The 1” steam main currently in question drops through the basement ceiling into a ½” steam trap which feeds into a 15’ horizontal pipe which then goes down directly into the wet return. I propose removing the steam trap and connecting the horizontal condensate pipe to the bottom of the tee. My plan is to come off the ½” tee opening with an elbow and head for the ceiling. Another elbow near the ceiling would head toward the dry return. I plan a Mepco 1E venting to the dry return in place of the radiator vent someone installed on a convenient tapped opening.

What have I missed? I have read the steam books several times over the last 5 or 6 years but most steam mains apparently are in the basement and crossover vents usually seem to come off the top.

I would welcome comments, advice, encouragement and/or redirection.

Thank you for your time

nicholas bonham-carter

A schematic drawing of the present layout would be helpful here. Is the Dunham Air Eliminator working properly?
Remember that these systems work best on mere ounces of pressure.--NBC

b_bz

Thank you for your response.

The vaporstat is set to limit pressure to 7 oz but I haven't seen the pressure rise above .5 oz on the 0 - 30 oz gauge. The Air Eliminator's float is gone but it lets the air out OK. I removed the marble that can allow a vacuum to form so it is essentially an open hole.

In the picture, the 1" pipe coming through the ceiling is the end of one of the 3 mains. The 1" pipe leaving the steam trap to the right goes approx 15' then drops to the wet return at floor level. Nothing goes into or out of that pipe between the steam trap and the wet return. I've been trying to put together a complete formal schematic of my system but am struggling a bit with what sort of format will show things most clearly. I will try to put together some kind of rough drawing later today.

Charlie from wmass

where are you located? There are people here who would do such work. Try the find a contractor section.

b_bz

Thanks @Charlie from wmass for the suggestion.

Alas, I'm located near Spokane, WA. We have one commercial steam company but there is minimal understanding of and next to no interest in a ~600 sq ft edr vapor system. I spent August through November trying to get a quote for a new boiler with no success. Now that spring is here, I will try again. Maybe work loads are different and they will have time to fit me in. I want to get my system in shape and running on the old boiler now so that the new boiler will be the only variable if we need to troubleshoot when it comes on line. We started insulating the mains on Sunday. There is a window of time this week that we could do the crossover traps.

Charlie from wmass

Yeah that is outside my travel radius. Do you have the Lost art of steam? I will look for a photo of a crossover trap piping diagram.

nicholas bonham-carter

In the museum here are some drawings of the typical Dunham piping. As I remember, the cross over traps are mounted higher than the dry return to prevent them from being waterlogged.
Double check your radiator EDR before ordering the new boiler.
Some people have restored the vacuum feature of those systems.--NBC

Jamie Hall

It is possible to mount the crossover traps on a vertical drip -- which is what you seem to be talking about. The trick is that they should come off the drip with a T, then elbow up with a short nipple, then elbow over to the trap (which, ideally should be above the dry return) and then go down (or over) to the dry return. That piping rig will keep condensate coming down the drip from getting into the trap.

JStar

That looks like a drip-trap, not a cross-over trap. It is most likely collecting water from the main in the ceiling. Can you take pictures of the Air Eliminator?

Steamhead

b_bz said:

The 1” steam main currently in question drops through the basement ceiling into a ½” steam trap which feeds into a 15’ horizontal pipe which then goes down directly into the wet return. />

This is pretty standard for overhead-main systems. What's missing is a way for the air to get from the trap outlet to the dry return. That probably explains the plugged tees you see.

b_bz

Thank you to everyone for taking your time to read my post and reply. This is truly an amazing place.

@Charlie from wmass I Have read the "Lost Art of Steam" several times during the last 6 or 7 years and refer to it often. I also have "Greening Steam" and "Every Darn Radiator." I find the books are both informative and inspiring.

@Jamie Hall your design suggestion closely resembles my best guess for this crossover trap. Thank you! I feel a lot more confident about it now.

We plan to start the project today. My husband will get parts this morning. Our nephew will come to contribute muscle in the afternoon. We'll see how things go.

@nicholas bonham-carter my boiler selection might be a thread of its own. I have lots of questions. Also, I have often dreamed of using the vacuum feature of my system. Right now, however, my focus is on getting a system that can retain its gravity-return function with one of those new-fangled, low-water-content boilers. (The 110 plus gallons in my 90-year-old Birchfield have been extremely forgiving of system deficiencies.)

vaporvac

Could you poast a pic of the air eliminator as @JStar requested. He's one of the pros (along with @Steamhead) so I'd be interested to hear his thoughts.

b_bz

Thanks again for everyone's interest and help. Below is a picture of the new crossover trap piping for the 1st steam main.

The next picture shows the Hoffman Air Eliminator. I believe that the crossover trap piping for the 2nd main should connect the plugged tee shown in the picture to the plugged end of the Air Eliminator. We installed the new 1" pipe you see (below the tee) in place of 1/2 inch piping which came out of the side of the tee, through a radiator steam trap and then down to the wet return.

It was a good day. I think we are now finished working below the boiler's waterline and the system is back and functioning as expected.

Steamhead

I see your Air Eliminator still has its original vacuum check screwed into the top- have you tried removing it to see if it helps?

Fred

Do anticipate that you will probably need to skim the boiler after it runs long enough to flush the oils from that new piping back into the boiler water. When you see the water in the sight glass sstart to bounce more than 3/4" or so, it will need skimming (a true skim, not drain). May take a couple skims to stabilize the water.

Charlie from wmass

did you save the marble from the vent?

b_bz

Steamhead said:

I see your Air Eliminator still has its original vacuum check screwed into the top- have you tried removing it to see if it helps?

Thank you. I will look into that.

Fred said:

Do anticipate that you will probably need to skim the boiler after it runs long enough to flush the oils from that new piping back into the boiler water. When you see the water in the sight glass sstart to bounce more than 3/4" or so, it will need skimming (a true skim, not drain). May take a couple skims to stabilize the water.

I do hope a skim won't be necessary but I'll keep a close eye on the sight glass. We'll do what we need to do.

Charlie from wmass said:

did you save the marble from the vent?

Yes, I have the marble and cap tucked safely away.