The King Of All Crossover Traps!

Steamhead

This is the Roland Park Condominium in north Baltimore, built in the 1920s. The first pic is the impressive front view. Look thru the archway and you can see the rear section of the building in the distance.



This system is currently a vacuum-return setup with mostly Trane traps, but was originally a Kreibel. We found and identified some of the old hardware. The boiler room is in the rear- currently housing two Weil-McLain 10-88s, and the original Smith Twin Tubular coal-converted unit that is abandoned in place. The original boiler also heated a garage in the rear of the building, but those lines have been disconnected since we now have automotive antifreeze.



We started working on this system a few months ago. Today's job was to vent the steam main- some 270 feet of 10-inch pipe running to the front of the building thru a tunnel-like hallway.

Steamhead

We found the biggest thermostatic trap available

a Nicholson C73HC. This thing has 1-1/2" threaded connections and an 1-1/4" orifice in the seat! You can also get it in 2" as the C83HC, which still has the 1-1/4" orifice. Naturally, you don't get the full 1-1/4" flow since the trap element hovers over the seat so it will close properly- but this is true of any thermostatic trap.



The principle is the same one used in old Vapor systems with traps, which sometimes used radiator traps as main vents, routing the air into the dry return. Same thing happens here, but on steroids.



We had a 2-inch drip near the end of the main to work with, that fed into an 1-1/4" F&T trap. We cut a tee into the drip line coming off the dirt leg and fed the Nicholson from that. The condensate continues to the F&T but the air can jump up and pass thru the Nicholson. The tee is 2-inch all the way around, and the reduction from 2" to 1-1/2" takes place in a reducing ell above the tee. In this way we reduce the velocity of the air as it leaves the main drip, so the water won't be pulled up toward the Nicholson.



This setup lets each trap do what it does best- the F&T handles the condensate, the thermostatic handles the air. We're not worried about such a large thermostatic trap wire-drawing its seat, since it handles little if any condensate.



We also included a trap-testing tee with boiler drain, and a plugged tee on the steam side where we can install a gauge if we need to.



Before installing this trap we timed how long it took steam to reach this point after reaching the header drip in the boiler room- just over 11 minutes. We got it down to just under 7 minutes with the new crossover trap online. This doesn't sound like much, but it means the system will balance a lot better, and the steam will reach the Heat-Timer sensor more quickly- it is mounted at the front of the building, as far away from the boiler as possible, as it should be.



These traps are definitely not cheap, and Spence (who owns Nicholson) took their sweet time shipping this one- some two months from when we ordered it! They really need to work on improving their customer service.



But it was the right part for the job, and required a lot less piping than a row of smaller thermostatics would have. We'll see how much gas they save this winter.

JStar

Sweet

What are the ratings on that crossover trap?

Steamhead

3555 pounds of condensate per hour

at 1 PSIG ΔP. I don't have the air-venting throughput, no one rates their traps that way- maybe Gerry and Steve could work on measuring these big traps.... pleeeeez?

JStar

Geez

Looking at their charts...



An open 1" pipe flows 11 CFM at a little less than 1/4 PSI.



So, you figure...1 1/4 orifice....1 PSI....



It would have to be close to 50 CFM or more. Holy cow!

Ironman

Excellent!

I would love to see that one in person. 90 years old and still purring along. And you've made it better than ever. Good job guys.



That drip looks like it might be a head knocker. I guess the dead men were a bit shorter than the average man today.

gerry gill

Thats really cool !

I had no idea that a thermostatic trap that gargantuan even existed..1 1/4'' orifice..wow.. i dont even think my flow meters could measure something that big..would probably just peg the floating ball to the roof of the device..how did you find that bad boy?

Steamhead

As I said earlier

the trap element's plunger restricts some of the flow since it has to be positioned to close properly. All thermostatic traps are like this. It wouldn't flow the same as an open 1-1/4" pipe, but it is still the biggest available.



We found it the modern way- went to each trap manufacturer's online catalog. No other manufacturer had anything with anywhere near that size orifice.



Gerry, maybe you can find a bigger flow meter?

SWEI

hallway photo

Is all that yellow spaghetti gas line?  I see more than a dozen, and they look like they might be 2" pipe.

MikeyB

yellow pipe

Nice work Frank, that yellow pipe almost looks like a type of innerduct for fiber/cat 5 cable etc.

DanHolohan

Endlessly fascinaing.

Never gets boring, does it? Thanks for sharing! 

Steamhead

Yup, it's spaghetti/CSST

the gas company made them consolidate all their meters in one location, so there's spaghetti all thru the basement. Not our work, obviously. 

Steamhead

Yup- that's why we do this work

and if it weren't for a book called "The Lost Art of Steam Heating".......



To get an idea of the fuel savings potential, the 10-88 boiler has a gas input of 3,100,000 BTU per hour. Dividing that by 60 (minutes in an hour) and multiplying by 4 (minutes we should save on each firing cycle) gives 206,666 BTU - just over two therms less for each firing cycle. The number of cycles per day depends on how cold it is, but those therms will add up over time- and the building will be more comfortable, so they might even be able to retune the Heat-Timer to shorten the cycle even more.



While I think of it, Dan- there is no vacuum equalizing line on this system. We know why it needs one, but one resident (an engineer) is wondering about the dip we usually find in the equalizing line that creates a water seal. We haven't been able to find any documentation as to why this dip/water seal is needed- do you have anything on it?

SWEI

consolidating meters

I've asked the gas company here about remote-reading gas meters and they look at me like I'm from Mars.  Does anyone do this along the lines of the electrical submetering we do in multitenant commercial buildings?

DanHolohan

Only purpose

Was to keep the check valve wet. I remember asking that a long time ago. It took me a while to get an answer, and when I did, I just laughed.

Steamhead

But it's the details like that

which make or break a job. Thanks!

Steamhead

Not that I've seen

the usual setup is either a meter for each unit and a "public" meter for the boiler and water heater, or just one meter for the whole building. In both cases the gas company owns the meters. The gas company does use remote reading.

Steamhead

If you ever come to Baltimore

get in touch.

Gordo

FLIR of the Mother Trap

Here is a FLIR of the Mega cross-over trap.  As you can see, the outlet of this trap is much cooler than that of the F&T trap as it is only passing non-condense-able gasses.

Charlie from wmass

the old swing checks

would not seal pushed by a gas like steam but could be pushed by the water. By the time the water was squeezed past the leaking check valve (as most swing checks do leak past some as they are not perfect seals) the vacuum cycle would be over. It is harder to push water through a hole then steam. Or I could be all wet.

Awesome and inspiring work as always Frank. Making it even better then the Dead Men did it.

Steamhead

"It is harder to push water through a hole then steam"

Just occurred to me- the same is true of fuel oil. That's why we don't use compression fittings on oil lines- they can leak air (which is a gas, just like steam) into the line, but not let oil leak out.



So you're not "all wet"- never thought you were, and this proves it.

Charlie from wmass

Thanks Frank

That is one of the best compliments I have gotten.

Steamhead

Update

the heating season has started, and they had to dial back the Heat-Timer. The entire building was overheating instead of just those parts near the boiler room.



Looks promising.

gerry gill

Thats great news!

They should be saving money now..it also helps prove the massive venting theory really works.

Steamhead

Update #2

Don't have the final numbers and degree-day corrections yet, but this one looks like a winner.



One corner of the building was a bit slower than the rest, so we added another crossover trap- a Nicholson A53 this time, next to a Sarco F&T which we moved over to accommodate the new tees. We also gave the Sarco a brand-new faceplate kit.

Dave in QCA

Fantastic!

As always, amazing work!  Thanks for sharing the project via pictures.

Steamhead

Ran the numbers today

fuel consumption didn't change from last season, but the heat distributed much better. In other words, the fuel wasted thru open windows now goes to the far end of the building where it's needed. They did pay less for gas this year, but that was due to a 14% rate decrease.



There is still work to be done on this system- in particular the boiler pressure controls, activating lo-hi-lo and tuning the burners. Presently another company services the boilers but we're working on that. We'll keep tracking this system.

vaporvac

Degree Day equivlent?

Although consumption was the same, did the calculations account at all for the difference in temps. Here in the Ohio river valley, last year was very mild with a very early spring. From March onwards it was in the 80s. This year, it's more normal ie. cold all winter with a damp, dreary Spring.

Steamhead

Yes we did

it ran between 13.5-13.8 therms per degree day. This did not include the average 700 therms per month used for the domestic hot-water system.

vaporvac

I figured you did

Oh well! I was trying. I am surprised there wasn't a difference, but as you say there is one in delivery and comfort. I'm sure if you're able to make those additional changes, there will be some reduction.

The Steam Whisperer (Formerly Boilerpro)

The savings may be hiding.....

If the units have indiviudal gas meters, you won't pick up the reduction in gas usage due to  people not using stoves for heating.  Also, you won't see the reduciion in electrical use because electric heaters are no  longer needed.

Steamhead

Every job is different

so it's hard to predict how the savings will work out.



Dave, yes the units do have individual gas and electric meters. I didn't recall seeing space heaters though.