Gorton Main Vent Survey

Dave in QCA

I want to first say that I'm not one to stir things up because I enjoy creating conflict, because I don't. But, I've been stewing on something for a few years. I first thought it was unique to my system, but as time goes on, I'm not so sure.



HERE WE GO.....

We all know that the Gorton #2 main vent has the highest capacity of any main vent on the market (When it's cold). But the question I have is this. During the heating season, how many mains cool off enough allow the G2 to fully open, or to open at all?



Gerry Gill, who I have enormous respect for reports in his Youtube video, <a href="http://www.youtube.com/watch?v=Wl8vQ2MYhMs">http://www.youtube.com/watch?v=Wl8vQ2MYhMs</a>

that the G2 will begin to close at 110F and will be fully closed around 130F. He warns that placement of the G2 in a boiler room that stays warm may affect its ability to operate properly.



It would seem to me that Gerry's advice is certainly correct. But, in addition to the ambient temperature in the space, the any main vent is going to be exposed to the temperature of the air that is inside the main. On mains that have no insulation, the cool down is going to be significant enough that the G2 will work just fine, I think. But what about mains that are fully insulated? How many folks have measured the temperature of their steam mains at the beginning of a cycle?



I'm sure everyone is really tired of hearing about my system..... But since I use a Tekmar 279 temperature control, I know the temperature of the end of the steam main, just a few feet before the venting point. The system is set for 1 cycle per hour. On very short cycles, say 3-4 minutes of steaming time after steam reaches the end of main, the main will have cooled to 145-150 by the beginning of the next cycle. On longer cycles that I'd see when it is zero outside, around 30 minutes of steaming after steam reaches the end, the end of main temperature will only fall to 175F at the beginning of the next cycle. As the boiler begins to make steam and the venting process begins, I can see the temperature fall 2-3 degrees as air from cooler parts of the basement is pushed through the portion of the main that's located in the boiler room. The temperature will hover around 169 until steam arrives, at which time it will shoot up to over 200F.



My experience when using four G2 vents was that they performed great on a cold start-up, but once the system was warm, they performed about the same as a threaded iron plug!



So, what I am suggesting, for the purpose of advancing the art of steam heating, is that everyone that is interested in this experiment take temperature measurements on the steam mains. The temperature should be taken with some type of accurate probe type thermometer that can be inserted though the insulation, taking the temperature of the pipe surface. Temperature at the beginning of the cycle prior to steam arriving is the critical measurement. Temps after steam arrival is also important to indicate the accuracy of the "cold" reading.



I'm looking forward to seeing the data start coming in.

I hope it shows that in most systems, Gorton 2s are working GREAT!. But,if it shows that most insulated mains stay too warm for the G2 to work once the system is warm, isn't that something that everyone would want to know?

JStar

G2

Why you gotta start trouble!?!



I don't think it's a problem. If they don't open, they also won't let air in. That's not a bad thing.



Waiting for MarkS to chime in with a 100 data point spreadsheet....

Dave in QCA

Sorry.... But, what about...

JStar, I'm all for keeping the air out, but on a most systems, its going to come back in through other routes, such as the radiator vents, or the main vent on a vapor system, because most air checks have been removed.



So, assuming that the system is not set up to drop into vacuum, there's going to be air in the main and we want to get it out fast, but vent the radiators slow.

Dave in QCA

duplicate post

JStar

Air

What vent opens at the highest temperature?



This debate may all end in the answer that thermostatic traps (open at 180F) are the best for venting.

Dave in QCA

Hoffman 75

The temperature range of the Hoffman 75 is essentially the same as a thermostatic trap, being driven by a capsule filled with an alcohol mixture. The range is 180-190F. Like the thermostatic steam trap, it pretty much stays open until steam is present.

Bill_110

Gorton #2 venting

I wonder if there would be value in venting your mains with different makes of valve? If the Gorton #2 is the only one that works on the bi-metal strip principle, then maybe having one or more of one of the other types on the same antler might serve as a useful insurance - like wearing suspenders and a belt, to take a line from The Art of Steam Heating.  I'm wondering too if it is a good idea to insulate the return mains after the last radiator. When I did mine I thought there would be value in keeping the condensate hotter so that it would boil faster when it got heated again, but if the returns can get too hot for the vents to work properly maybe that is more important?

Jamie Hall

Interesting...

Thank you Dave for at least starting me thinking!



However... for my system, and unreconstructed vapour system, the point is moot.  The venting in my system is accomplished through crossover traps -- as somebody noted, fully open at temperatures below somewhere around 190 or so -- which go into the dry returns and thence back to a single vent cluster at the boiler -- one Gorton #2 and the original Hoffman vacuum vent (76).  It is a big system, as residential systems go, but that venting is perfectly adequate.



The Gorton does create a problem in one regard: the Differential Loop functions by hitting the vents with steam, at which point they close abruptly.  And respectfully declines to open again until it cools off (which it does, eventually).  But this is not a handicap -- as the steam condenses in the return, the pressure drops quite naturally.  And it works as it is intended to..  and, of course, the 76 behaves as it should.

ChrisJ

Heat

I also was concerned with this even using Gorton 1s before I insulated my piping.  My crawl space went from not bad to colder than a cast iron commode on the shadier side of an iceberg so I no longer worry about my vents closing.  It was amazing how much of a difference insulating my 15' of dry return made in that crawl space.



I'm not sure about the G2 but I would assume it's like my Gorton radiator vents and those I can tell when they start closing by sound.   Have you listened to yours at the start of another cycle when you fear they might be partially closed?  Perhaps even hitting them with a cheap IR thermometer would be enough?  If the vent only measures 90F at the start of a cycle you know you have nothing to worry about.



One concern I would have is a vent that closers slower, should in theory also waste more water.  Although that doesn't seem to be the case with Gorton VS Hoffman 1As in my house.

Dave in QCA

I restore my crossover traps too.

Jamie, yes, you'res is working like a charm I'm sure. In frustration resorted to going back to Dunham/mepco 1E traps as crossover traps. One vent point on the return, an open pipe with a swing check on it. It also is working like a charm! In this spell of real cold weather, the system was dropping to 8" vacuum between cycles. No worry about getting the air out when it can't get back in.

gerry gill

Interesting thought Dave-

i hadn't really dwelled on that..perhaps a way to test would be an antler with say four gorton 2"s and then a subsequent test with a hoffman 75 in place..you do bring up an interesting scenario tho. Maybe another way to tell is to hold a smoke pen by the gortons on the next cycle and see if they are venting by watching the smoke steam???

Dave in QCA

Your expertise will be invaluable

Gerry, I was really hoping that you would jump in on this topic.



What brought it to my attention as watching my system a few years ago, before the boiler install and going back to crossover traps. I had timed how long it took for steam to get to the Tekmar condensate or end of main sensor. Then, at a later time, on a warm start, I was timing it again. I thought the steam would never arrive! I felt the G2, and it was warm, but not hot. And, it was closed. I quickly removed it from the antler and air came rushing out! In a short time, the steam had arrived. I thought I had a faulty G2, but then after research and finding your data, learned that it was never going to be open at the temperature of my mains and the air in the mains. This has been bothering me ever since.



As Dan says, there's a lot of real smart people on here. It will be interesting to see ya'all figure out.

SWEI

Thermostatic traps for venting

comes up yet again.  I'm all ears...