Large Venting Job / Nicholson Trap

JStar

Just wrapped up a major venting upgrade in NYC. We took out a bunch of tiny Dole vents, and added a whole slew of Gorton #2's. The system had about 60 feet of 6" main and up to 100 feet of 3" and 4" mains. Obviously, those tiny Dole's were not doing much. We had a lot of cubic feet of air to deal with.



On the long 6" main, we installed a Nicholson C73HC thermostatic trap as the main vent. I saw Steamhead use this on a job a while ago, and couldn't wait to see this trap in action. It is the equivalent of 20 Gorton #2's. The main was hot in 5 minutes. Impressive!



We used 35 Gorton #2 vents in total across the whole system. We'll be going back to add vents to every 6th floor riser.

SWEI

Nice work

great to see the use of a thermostatic trap on a main.



I'm curious about the feasibility of using a radiator trap -- perhaps something about equal to four Gorton #2s?

JStar

Traps

Monash #48 vents about the same as 2 Gorton 2's. We'll be using a few of these on an upcoming job.

SWEI

Nice

...and I'll bet they take up a lot less space.  Given some of the tight basement overheads I've seen, that could really prove useful.

JStar

Traps

The small profile of the traps has really convinced me to start using them. The Gorton 2's are about 6" tall and hard to fit everywhere. The Monash #48 is about 3" tall. It's also twice the price of one G2, but vents twice as fast. Even trade.

MDNLansing

Vacuum

The Monash 52 with a swing check worked very well on my vacuum system. Leaps and bounds better than a cluster of Hoffman Vacuum Vents. Installed on a slight incline, the condensate between the trap and check valve drains right back once it cools.

ChrisJ

Steam loss

I know this is kind of a hard question to answer, but do you feel there is more steam loss using the trap over a vent?  I'm up to 5 G1s on my one main because I can't fit a 2 due to height.  I'd consider sticking a trap there but don't want to increase loss and I know all vents loose some albeit very little when working properly.

MDNLansing

I don't think so

My "trap vents" are on my air return line so I do loose some steam there. My system puts "cooled" steam at the vents for about a min before they close. The steam from the radiators makes it to the vent and it has cooled just enough to not trigger the element, but still be hot enough to have moisture in it. So, I do get some steam loss. However, I get it with the vents too. There isn't any noticeable difference between the traps and vents in my installation.

ChrisJ

Loss

The only reason I though of it was ever since switching to Gorton's from Hoffman's my system uses a little more water.  Not a lot more, but its definitely noticeable.



However, I no longer have problems with radiators randomly not heating and there is no more click clacking so I'll never go back.  I also added more vents at the same time so that might be part of the extra loss.



Some guys say you shouldn't lose any steam but that doesn't seem possible to me.  Some must escape while heating the vent no matter what type it is.

gerry gill

Nice job Joe!

i am impressed!!!!!!

MDNLansing

You'll Always Loose Steam

I don't think there is any way to avoid this. There will always be a short period that allows moisture to escape from the vents. And when the boiler cycles are close together, you're going to get some latent moisture carried out with the venting air. You could possibly install a copper coil on the exhaust of the vents and condense it down to room temperature, then recover the water to the system using another trap. But how feasible is that when you can just add the little bit of water you are loosing? These are pretty tightly sealed systems, but their certainly not perfect. That's why we have water supply lines piped into them.

Toymotorhead

Output of trap/threaded connections

I like the trap idea, but I wonder if it might be worth it to not end it with a threaded fitting (like the discharge of a float type LWCO) to prevent some future slack jawed knucklehead in the future being tempted to plug it. Nothing looks as tempting as a threaded open fitting for someone who does not get what is going on. (Quote: See Mr building owner, that old guy just left this open pipe here, he must have been a moron, could have messed up the whole place.....)



Or alternatively screwing something on the output, like a floor drain strainer. Just a thought.



Cheers

Richard.

MDNLansing

Notes

At the risk of getting off topic.... I am shadowing an old steam fitter and he leaves a journal notebook with every system he installs or works on. He adds any notes he thinks might be relevant to someone down the road and chains it to the boiler using a screw in the jacket. Might be making it easier for the competition some day, but he knows if the customer is happy his competition never gets in the door anyway. Great idea for a homeowner to do for sure.

JStar

Gerry

I wanted to send this trap to you, somehow, to test it's venting capacity. Never got around to making that happen. Let's just mark this one down as FAST!

BobC

Logs

I've kept a log of my system for years, it helps jog my memory and has saved me a lot of time and consternation.There is only so much consternation so you have to use it carefully.



Bob

mcsteamy

Steam Loss

I seem to have had a lot of initial loss when I switched to B&J 134A traps, and again when I added another trap, but then it got back to normal.  Whether it was just coincidental, I don't know.  I have one more to add, so we'll see what happens. 



Here's a chart, though, which caught my eye:  http://www.marsh-steam.com/pdf/steam_traps_marsh-aquatrol_2.pdf



Look at the EDR on the Aquatrol A6A, which is supposed to be a Monash 6B equivalent.  Typo?  The other traps that are rated in EDR generally seem to follow their tested ratings.  Theoretically, there seems to be no good reason why a trap used as a vent could not have a massive orifice in it without increasing the cost.  If someone had the inclination to design a trap with a 1/2" orifice in it, the sale of Gortons would probably drop through the floor.

SWEI

Thermostatic traps as vents

Seems like something that used to far more common, most notably as crossover vents.  Joe tells me they work just fine even though they are installed "backwards" (since there's no condensate to drain) which brings up a question:



Need to convert pounds per hour to CFM -- what ∆P should we assume when they are used as vents?  I'm guessing 1 PSI (which Nicholson shows in their docs) but for something like the Marsh PDF above, where it shows "Max Lb/Hr" I'm less certain how to rate them.

MDNLansing

R&D

Using traps for venting makes me wish more companies were doing R&D for residential systems. I agree with you, with the proper resources someone could make a new style main vent that would give Hoffman and Gorton a run for their money. Makes me wish I had an industrial metal shop. Of course, if I did my wife would probably file a missing persons report on me.



I don't think the A6A is a typo though. The ratio of lbs/hr and pressure to the EDR is the same as the other traps. That's quite an impressive number if it's legit. Who knows how these are really tested and rated though. There are a lot of variables that can affect those numbers.

JStar

Pressure

We need to test all vents at 1 ounce. The idea being that all boilers start at 0 psi. They need to vent as soon as the boiler makes the smallest amount of steam.



Man, I really wish that I had tested this trap before installing it. Right now, I only have theoretical numbers.

MDNLansing

2 oz for mine

When I tested mine (after several runs had deposited some condensate), I taped a piece of toilet paper over the end of the vent pipe, and installed a low pressure test gauge on a T, 3" before the trap. Gauge read 1.8 oz when the paper began to move. This was without using the swing check though. The addition of the check valve undoubtedly delayed the venting. I haven't tested with it in place, but I will do so tonight.



I'm curious how much trap design has to do with this. Is one trap better than another?

JStar

Traps

The Nicholson seat opening was a full 1-1/2", with the seat disc hovering about 1/2" above.



The Monash #48 has a big enough opening that I could breathe through it comfortably for a long time. It takes no effort to pass air through it. Smaller traps, obviously, have smaller orifices.



And, that's about as technical as I've been about it so far. Breathing heavily isn't exactly scientific, but it proves a demonstrative point, which we all know already. Find the trap with the biggest opening (disc type seat, not pin type).

MDNLansing

Good Thing?

Is there any disadvantage to this? I recall reading some threads in the past that said to add main vents until you only have a few oz of back pressure. I've never read the reason for this though. I've also read posts that say it's impossible to over vent the main. Is there a specific problem with no back pressure venting?

JStar

Pressure

I've always found that our systems never build any detectable pressure above 0-1 oz. until the vents close. I would rather vent the mains as fast as an open pipe will, and only let the system build pressure when the end of the main is hot. That guarantees even distribution to all radiators. Same idea goes for two-pipe orifice systems, get steam to all of the orifice plates at the same time, and then build enough pressure to push through each radiator evenly.

vaporvac

Trane Air Eliminator

It will be interesting to see how the vent on the Trane Air Eliminator reacts to the new boilers. I've never read anything about changing that vent or if it's even possible without destroying the vaporvaccum system. I suppose in the old days the coal boiler would run pretty much all the time and air wouldn't re-enter too much? I wonder how it worked in my system with the original firetube boiler, since the coal boiler was only for "back-up".

MDNLansing

Makes Sense

That makes sense. Now that I think about it, I was measuring back pressure on the air return line. My mains vent fast with almost no back pressure, but the air line vent trap does have a little. There was a tremendous difference once I added trap vents to the mains. Originally, the mains vented with an orifice into the returns. I have modified it to vent to the atmosphere, then into the returns once those close. I decided to try the traps for venting because I was looking at adding 8 Hoffman #76's and wasn't all that excited with the price of that. Now that I've used the traps I think I prefer them over the Hoffman's anyway. I reduced my fire time by 40% using the trap vents.

SWEI

Thermostatic traps as vents

I think there are two figures here.  The first is the cracking pressure.



The second is a CFM versus pressure curve, or CFM ratings at various low pressures.  The manufacturers' ratings are at 1 PSI or more and are given in pounds per hour or EDR.  Might have to build a jig and instrument it to get these.

Steamhead

Nice Job!

the only thing I would have changed is to turn the trap on its side, have the steam coming into the side (usual inlet connection which would now point down) and the bottom (outlet) discharging horizontally into the standpipe. This would keep steam in the trap body so the bellows wouldn't open and close so much, and allow condensate to drain better.



And for those who haven't seen ours, here it is. This one is piped as a crossover trap rather than a main vent, but it does the same thing.



http://www.heatinghelp.com/forum-thread/142217/The-King-Of-All-Crossover-Traps