Dave in QCA
Joined on May 6, 2010
Last Post on February 28, 2014
@ February 28, 2014 9:36 PM in Pickup factor. Help me understandThis is a somewhat difficult subject to understand and its an even more difficult subject to explain. I have to bow to Jamie for his analogy to the accelerating car, it is excellent!!! I had never thought of it in that way before, but it's spot on!
I'm going to jump in and give my 2 cents too and see if I can help to make it easier to understand too.
The "pickup" factor is actually two separate factors that have separate purposes. First, the piping loss factor takes into consideration that piping will give off heat and in doing so will condense steam, even after it is fully heated up. So, in order for a boiler to be able to maintain a fully heated system of radiators and piping at full temperature and and maximum output, the heat losses or emission of the radiators and the heat losses of the piping must be matched by the output of the boiler. The amount of heat loss from an average piping system that is insulated is estimated at 10% of the capacity of the radiators. So, if the radiators on a system add up to 200 Sq Ft, the piping losses can be estimated to be equal to an additional 20 Sq Ft of radiation.
But, the piping loss factor only takes into consideration the piping losses of a fully heated system. Steam systems by their nature are difficult to heat up in an even manner. By comparison, a hot water system uses a 15% piping loss and pickup factor, or only 5% pickup. The result is that old gravity hot water systems with huge cast iron radiators are very slow to heat up, but they do eventually heat up. In the heating process, all of the radiator will heat up gradually and all at the same time. Starting from stone cold, to luke-warm to warmer, and eventually hot, if the boiler has been firing continuously. The key point is that the radiators throughout a well designed system will heat uniformly.
This is not the case with a typical steam system. On a steam system, an additional pickup factor of 24% on insulated piping is needed. On a typical steam system what would happen with a boiler sized too small to give adequate pick-up, some radiators will heat first, and others later, sometimes not getting any steam at all until other radiators are blazing hot. The negative effects of unbalanced steam distribution are especially undesirable in mild weather when steaming cycles are short and only partially heat the radiators. Undersized boilers in these situation will often leave some of the radiators with no steam at all.
Fast vents on steam mains will improve the likelihood that steam will arrive at the radiators at the same time. Slow, make that VERY slow radiator vents will further improve even distribution. Actually, I have seen some cases where marginally sized boiler worked just fine, but the size of the mains were small, reducing the amount of heat loss and the vents were all Hoffman #40s, which are pretty slow.
The negative aspect of using the 34% piping and pickup factor for insulated mains or the 50% piping and pickup factor for uninsulated mains, is that on long cycles, when the system becomes fully heated, the boiler will start cycling off and on because of pressure. It is just a part of the beast. Of course, as has been mentioned, two stage firing is a great benefit in this situation.
It should be noted that in two pipe systems, when inlet orifices are installed on the radiator, since they separate the radiator from the boiler and main pressure, the pickup factor can be omitted. Only the piping loss needs to be factored. Also, according to writing by Dave Bunnell, aka, the Steam Whisperer, if very slow vents are used on one pipe systems, the pickup factor can sometimes be omitted as well.
Hope this is helpful. on some level.
@ February 6, 2014 9:54 AM in An Epic Tale: I hear the Trane a comin'!Colleen, Now you're really having fun! And, staying warm too! I don't know how you have tolerated not having heat for so long!
Regarding your main vent. That little vent on top of your return trap is not the ONLY vent is it? I was thinking that you had a mercury pot on your system. If so, the venting is running through that pot.
@ February 4, 2014 10:27 PM in MegaSteam short cycling on pressuretrolWhen the boiler runs an extended time and the radiators become fully heated and the pressure builds up, the pressuretrol shuts the boiler off until the pressure drops, which will occur quite quickly, as you have reported. This is completely normal. In most normal cycles, except when it is extremely cold, this will not occur.
@ February 2, 2014 1:51 PM in remove insulation on one pipeAs I recall, this saga has been going on a LONG time. Too bad for such an attractive building in a great Chicago neighborhood, that it is proving so difficult to get something that should be simple accomplished.
Running my building in Davenport with a set point of 71. Yesterday I checked and the south 1st floor was 71, the north first floor was 72. The third floor was 72. Of course it was a cloudy and there was no solar gain on the south side. But I have to tell you that we get zero complaints about temperature. The system works great. And, since it was balanced, and a new boiler installed, which happens to be a smaller version of yours, it being a Weil-McLain 680, our bills have dropped by 33%.
How much money has been wasted by over heating parts of your building? How is the undesirable heat affecting property values?
@ February 2, 2014 9:14 AM in remove insulation on one pipeTaking the insulation off of the steam main is somewhat equivalent to installing a small radiator in the space. The steam main will condense more steam with it bare than with it insulated, but normally that will not cause a problem. Many systems operate with uninsulated mains because heat is needed in the space where the mains are located.
It would cost less to leave the basement space unheated, but if for whatever reason that is not acceptable, the operating cost difference is that you're now providing a little heat to that basement space.
@ February 1, 2014 3:39 PM in Gorton Main Vent SurveyGerry, 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.
@ February 1, 2014 3:18 PM in An Epic Tale: I hear the Trane a comin'!I'm so glad to hear that your project is coming to completion, and it sounds like you have lucked out in finding someone who loves steam to help you finish up! I'll be waiting for more news.
@ February 1, 2014 2:31 PM in Gorton Main Vent SurveyJamie, 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.
@ February 1, 2014 1:18 PM in Setting Vaporstatit is standard on the lgb-6 and above. But, their would be the ability to order other control options, so its impossible to say "ALL". check your wiring diagram. Check the second gas valve. If it has 3 wires coming out of it instead of 2, like the first gas valve, you know you got the two stage valve.
@ February 1, 2014 12:33 PM in Setting VaporstatI've never come across one set up as 2 stage. Most don't know it is even on there.
@ February 1, 2014 12:30 PM in Gorton Main Vent SurveyThe 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.
@ February 1, 2014 12:12 PM in Gorton Main Vent SurveyJStar, 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.
@ February 1, 2014 12:02 PM in Setting VaporstatActivate the 2-stage function of your boiler. If you look at your wiring schematic, you will a notation for firing rate control. You can use your vapor stat for that, or purchase another and use one vapor stat for an operating control and the second vaporstat for HI-LOW control. When the pressure opens the contact on the vaporstat, the HI-LO valve will go to LOW FIRE. If the pressure drop, it will go back to HI FIRE. This will be a more effective control that ON/OFF, and from what I am told, the LO FIRE function on the LGB boiler is about as efficient as the HI FIRE.
@ February 1, 2014 11:56 AM in Gorton Main Vent SurveyI 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, http://www.youtube.com/watch?v=Wl8vQ2MYhMs
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?
@ February 1, 2014 9:48 AM in Can anyone identify this Radiator?Gerry, I can see the image was scanned from a page in a booklet. Is this booklet something that is not in the HH Library? If there is more information there, could we get you to scan it and send it in to Dan?
@ January 19, 2014 2:54 PM in Identify Radiator Type, PleaseI am attaching a table that was taken from an ASHRAE publication back in the 1960s. I find it VERY useful.
This is not all inclusive, as there are certainly some exceptions. American Radiator Italian Flue type rads have 3" spacing and great sq ft per section than a comparate 3 column radiator. Also, most of the American and US Radiator 4 column models also had 3" spacing.
@ January 19, 2014 2:30 PM in Identify Radiator Type, PleaseMeasure the thickness of the sections. That is, from joint to joint. that will tell you the thickness of the sections. Thin tube are 1 3/4" thick. Regular Tube, also called Thick Tube are 2 1/2" thick. Once you know which type they are, then find the matching radiator in the charts.
@ January 17, 2014 12:06 PM in 66 degrees on first floor, 78 on second - how to adjust?When the radiators were originally sized, they were intended to heat the upstairs rooms that had zero attic insulation, meaning the ceiling was very cold. Once attic insulation is added, the heat loss of the upstairs is dramatically reduced. I have a hot water system at home and the upstairs will be about 5 degrees warmer than the downstairs if all the radiators are on wide open.
In the case of the original post to this thread, the situation is made much worse by the enclosures on the radiators. There was a time when folks thought it made the room look better, but I for one appreciate the looks of the exposed radiators. I do paint them with paint that approximates the original bronze paint that was supplied by the radiator manufacturer. I know that paint reduces heat output theoretically, but it is minimal compared to an improperly constructed enclosure. And yes, there are types of enclosures that will actually improve the performance of the radiator, but the ones shown at the beginning of the tread are certainly not them.
I think you will need a 2-part solution. TRVs on the upstairs radiators and getting rid of or greatly modifying the enclosures downstairs.
@ January 17, 2014 11:28 AM in Still have hammer, out of ideas...I am familiar with the helical piers. That should be a great thing for your house and should last a very long time! At our Grandview property, we used the same devices, except installed as helical tiebacks, 24 of them! They were used to provide lateral stability to the foundation and an auxiliary support structure adjacent to and tied to the foundation of the garage building. It is at the edge of a 50-60 ft bluff and the wall was beginning to move laterally.
@ January 17, 2014 10:19 AM in Identify Radiator Type, PleaseI can see the manufacturer's name in the casting on your photo. American Radiator Company's venture into "modern" tube type radiators was named "Corto" They went to great lengths in describing you beautiful and modern they were.
From "The Ideal Fitter" 21st edition, 1925, American Radiator Company:
"Corto, the Radiator Classic, is the creation of Louise Courtot---a French artist engineer long affiliated with our Company. he labored for years to realize the ambition which he has expressed in these words:
"My ambition is to design a radiator of such refined and artistic elegance, one so repeating the chase lines of classic architecture, that in its finished state it may justly be regarded as an object of art."
It is interesting to note that the Corto radiator at this time had 2" thick sections. However, by the 1930s, American was producing radiators that looked exactly the same as the Corto but the sections were 2.5" thick, the same as the rest of the industry.
Always confusing is the fact that this first phase of tube style radiators are not "small" tube radiators. They are either just plain tube style, or large tube style. This is an issue that Dan has confused in TLAOSH. Much later, the slenderized "small tube" radiators were introduced with sections 1.75" thick. These were produced mainly after WW II, or perhaps beginning in the very late 1930s.
@ January 17, 2014 9:48 AM in Still have hammer, out of ideas...Nick, Thank you for taking the time to let us know how this turned out. Do I understand the project to mean that you actually had the entire structure lifted up off the foundation and leveled?