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Another Steam Boiler Sizing Concern

jcbjcb Posts: 13Member
Sorry for my prior "non-post", but for some reason it worked. So here goes:



My relative is about to replace his 1930'ish oil fired steam boiler with a gas fired unit. He has had several quotes and both contractors have come in with 120/125,000 mbtu input units, one a Slant Fin and the other a Weill Mclain. As I figure the origial boiler was likely oversized, I asked him to compute his EDR to see whether the size quotes made sense. He did this and came up with 288 sq.ft. So if my math is correct:



288 x 240 = 69,120 x1.33 = 91,930 = DOE Heating Requirement



Based on this it appears that these two quotes make sense, especially given he has an inboard row home with his neighbors helping to heat both sidewalls. So while perhaps a "done deal", I"m not one adverse to making things more complicated. I've read on a number of threads about some gas powered boilers that achieve around 85% efficiency. So while I thought this may be an option, I soon learned that the smallest Slant Fin gas powered unit has an input of 154,000 mbtu and produces 408 sq.ft of steam. As I figure only around 300 sq.ft of steam is needed, I'm concerned that the larger unit may be oversized enough to reduce its efficiency to the point it is a "wash" with the smaller units in terms of actual gas/utility bill usage. So it wouldn't make sense to do this unless these powered gas burners can be throttled down enough to meet his application. This may be possible to some degree, but I don't know of any possible adverse effects in doing so. It also wouldn't make sense if the end usage results are close in that the powered burner appears more complex and is noisier. Also, in this case. a unit this large may require a larger gas meter or gas main to the house. That would not be an added cost in this case, but just add to the complexity of the job.



So I would appreciate any comments as to whether I'm seeing this right or am I way off base (a distinct possibility !). I would like to see him get this job done right because, as you know, most homeowners only have this opportunity once or twice in their lifetime.



Thanks For Listening !
jcb
· ·

Comments

  • Jamie HallJamie Hall Posts: 3,988Member ✭✭✭
    A properly tuned

    gas boiler, whether powered or not, should be able to achieve 85% efficiency.  So that is not a consideration.



    What is far more important is that the boiler be sized to match the radiation, which your contractors appear to have done.  An oversized boiler will be nothing but trouble.  Don't do it.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
    · ·
  • JStarJStar Posts: 2,396Member ✭✭✭
    edited July 2014
    Boilers

    Most atmospheric, natural gas, boilers will not operate above 82% combustion efficiency. A wet-base and power burner combo will achieve 84-89%, with the added bonus of being able to fine tune the proper input rating. You can "under-fire" and power burner by about 20% without any problems.
    Post edited by JStar on
    - Joe Starosielec
    732-494-4357
    j.star@thatcherhvac.com
    http://thatcherhvac.com
    http://facebook.com/thatcherhvac

    Guaranteed performance. Guaranteed energy savings.
    Serving all of NJ, NYC, Southern NY State, and eastern PA.
    Consultation anywhere.
    · ·
  • Jamie HallJamie Hall Posts: 3,988Member ✭✭✭
    didn't know that, Joe

    I thought they were a little better than that.  Charles tells me that Cedric, my nice Carlin fired oil burning Weil-McClain, manages about 85 after he's finished playing with it, so I figured a gas unit would do as well...
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
    · ·
  • JStarJStar Posts: 2,396Member ✭✭✭
    Eff

    Any power burner, whether its oil or gas, will run around 85%.
    - Joe Starosielec
    732-494-4357
    j.star@thatcherhvac.com
    http://thatcherhvac.com
    http://facebook.com/thatcherhvac

    Guaranteed performance. Guaranteed energy savings.
    Serving all of NJ, NYC, Southern NY State, and eastern PA.
    Consultation anywhere.
    · ·
  • jcbjcb Posts: 13Member
    Boiler Sixing

    Thanks to the two "J's" ( Jamie & Joe ) for the input so far. One thing I've always found to be beneficial about these forums is that when two guys who know more about the subject matter than I do enter into a discussion, it benefits all of us non-professionals. In any case, I have a few comments (as usual) on what's been said so far.



    From what I've read on the threads so far, I would have to agree with Jamie that the starting point and probably most important item is to get a good match between the boiler and amount of radiation. As the radiator style has an impact on this, at some point I want to verify this with my relative to make sure his EDR calc is close. ( He said the contractors took a look at them, but he hasn't seen an EDR calc from them - something I would think they should be willing supply upon request. If they don't have one, it would make me wonder ! ).



    As to efficiency ratings, the only thing I have to go by is the boiler manufacturer's AFUE specs. I think we would probably now all agree that the gas atmospherics come in at around 81/82 %.  There are fewer gas powered ones to look at, but as Joe S pointed out most specs that I've seen show them at 85/86%.



    Now it was good to hear that the gas powered units can be "under-fired" by as much as 20% without problems. I went to the Carlin website and it certainly appears this is no problem on the burner's end. By using different plates/baffles the same burner can be adjusted to deliver a broad range of gas inputs - from 50,000 to 275,000 mbtu. But I still have this lingering concern that in a situation as this, throttling the input from 154,000 to a more palatable 125,000 has to have some adverse effect on the boiler's AFUE. From a non-professional point of view, it just seems that a manufacturer builds his unit to achieve a certain goal - in this case btu/steam output at given rate and then provides a firebox size with the correct number of sections to achieve it with the necessary btu input. Once that input is altered, all bets are off. Probably a dumb analogy as most are, but it's sort of like taking an old big Caddy that always comes with a big V-8, and putting a 6 cyl in it to save fuel or whatever. It will probably still get you where you want to go, but at what expense ?



    Just a side note : The 154,000 gas powered Slant Fin is an Intrepid TR-30.1.1. There is an Intrepid TR-30H that at 140,000 would seem a better fit. Problem is that it is only rated for oil and not gas. Wonder why ?



    So much from a non-pro's perspective. Hopefully there will be more input to help guide me along.



    Thanks Again !
    jcb
    · ·
  • JStarJStar Posts: 2,396Member ✭✭✭
    Boiler

    Under-firing a burner in a wet-based boiler will INCREASE heat transfer and combustion efficiency. So, it's actually better to use a slightly oversized boiler, and use the correct sized firing rate.



    I thought that the Intrepid was approved for gas. A quick call to Slant/Fin would confirm that.
    - Joe Starosielec
    732-494-4357
    j.star@thatcherhvac.com
    http://thatcherhvac.com
    http://facebook.com/thatcherhvac

    Guaranteed performance. Guaranteed energy savings.
    Serving all of NJ, NYC, Southern NY State, and eastern PA.
    Consultation anywhere.
    · ·
  • icesailoricesailor Posts: 7,265Member ✭✭✭✭
    Opiniions &Understandings:

    Its my opinion or understanding (take your pick) that with atmospheric gas burners (open tray type burners) are limited to the amount of air you can get into the burner process. Only the room atmospheric pressure can push air into the combustion process. With "power gas burners", you can jam more air into the mix of gas to get higher efficiencies. Like adding a supercharger to a car engine. Or a diesel. The more air fuel you can inject into the combustion process, the more power you can develop. Think of it in a way, like a turbocharged diesel. Once the initial compressed air charge is introduced to the cylinder, and the intake valve closes, the heat of compression explodes the fuel and the injector continues to feed fuel through out the combustion/power stroke process. The gas and oil power burner process is this in reverse. The fuel is forced in under pressure, and the air is blown under pressure. In both cases, air pressure control determines efficiency. You can futz with fuel pressure but with gas, you are limited to the fuel pressure provided by a regulator or the supplier. In both cases, the fuel is introduced into a confined space.

    Oil was always set at 100# pump pressure until someone figured out that you could get better fuel atomization with higher pump pressures. The droplets of fuel became smaller and more of the fuel droplet was exposed to air.

    The big difference with both fuels is that oil will smoke, soot and create CO. Gas just creates large amounts of CO. If it smokes, you REALLY went off the rails.

    I'd be carefully measuring those radiators to determine EDR. I've measured a few cast iron radiators in my time. My ears are getting hot thinking about remembering the EDR ratings of sections for all the different types of radiation. I found that I always had to count the sections on each and every radiator and total the sections for the EDR. But I'm mathematically challenged. Some have better number recall that I do. I can't just look at a radiator and know for certain how many EDR it puts out.

    You don't need a Master's or Doctorate in Physics to figure out the EDR of the radiators. If it is in the ball park and the boiler is big enough but not way too big, you are confirmed. If it is way off, you can ask questions. None of us are perfect. Especially when quoting prices to price shoppers.

    JMO.
    · ·
  • jcbjcb Posts: 13Member
    Gas Fired S/F Intrepids

    Joe S.,



    The first posts I read were from back in 2010 and at that time there were questions about gas fired Intrepids. Seems that while some were, S/F had not updated their spec sheets to reflect that. The spec sheet that I pulled up from their website a few days ago show most models as both oil and gas fired, but the two with less than 154,000 input (the TR-30H and the TR-20 ) show only being rated as oil fired. (There are also thee higher input models with H designations that don't show gas ratings.). I suppose it is worth calling them to see if their chart is up to date.



    As to your comments concerning under-firing and efficiency - I've read thru it a half dozen times and this is my interpretation of what the results would likely be in this situation :



    Install the 154,000 Intrepid TR-301.1 and throttle the burner input back about 16% to around 130,000, which would seem to be in the acceptable range for what is needed (my non-pro opinion - also I'm assuming that 16% is in the range of "slightly" under-firing a designed boiler size). As the gas AFUE spec for that unit shows 84.1%, the result would be that it would hold at least to that efficiency, and may well increase a bit more to over 85%.



    Please let me know if I'm understanding this correctly. Please know that I'm not trying to put you on the spot. I've read enough of these threads to know that there are many different points of view between those who I regard as experts in this area. After all, I know there is still some "art" in all of this based on experience, and that looking at the specs/charts doesn't tell you everything.. I'm sure if another expert has a different opinion, I'll hear it !   I would also like to hear supporting opinions if that's the case.



    Thanks Again !.
    jcb
    · ·
  • jumperjumper Posts: 483Member
    blower energy consumption?

    Even if power burner burns less gas than atmospheric; what about the electricity the power burner needs?
    · ·
  • RobGRobG Posts: 1,446Member ✭✭✭
    Quotes

    In regards to the the fact that the quotes provided do not show the EDR but only the basics of the job. Most contractors will not provide the details (I.E EDR, heat loss, miscellaneous parts to be used in the installation until the contract is written). The reasoning is that if it is given to the client at the time of the estimate the price will be shopped around and someone else will get the job as they did not have the expense or possibly experience to do the initial footwork themselves.



    Rob
    · ·
  • jcbjcb Posts: 13Member
    Gas Powered burner Energy Consumtion ?

    Jumper,



    That's a very good question that I haven't considered. Wonder if it has been discussed on any of The Wall threads ? If I can find out any info on this I'll post it.



    Somewhat related to this is another minor(?) negative of using 120 AC in that it presents more of a problem during power outages. Not that I have had to deal with it, but I suspect the lower voltage control systems are easier to work around in such situations.



    Thanks For The Input !
    jcb
    · ·
  • SteamheadSteamhead Posts: 9,102Member ✭✭✭
    On the Carlin EZ-Gas

    they use a 1/12 HP PSC motor, so it doesn't take much electricity to run. You can get away with the smaller motor because it isn't driving an oil pump, just the fan. I believe the Midco EC series and the Riello gas burners also use PSC motors. Not sure about Wayne.



    Note that on the EZ-Gas, according to the factory rep a standard Carlin 1/7 HP PSC oil burner motor can be used to replace the original one. This would, of course, use a bit more electricity.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    · ·
  • jcbjcb Posts: 13Member
    Powered Gas Burner Cost

    Steamhead,



    First, let me say I recognize your name from the 2010 threads as one of the experts on gas powered steam boilers, so I welcome your comments and appreciate your input.



    I had no idea of the cost to operate a PSC fan blower motor, so based on the info you provided I did a web search for KWH cost to operate a 1/12 HP PSC motor. (Note that most of the stuff that comes up talks about the benefits of the newer ECM motors, but I don't know whether those makes sense for this application). After most articles made my head spin with very technical electrical engineering information, I hit on one California study that said a 1/12 hp PSC motor consumes 0.218 KWH. So to try to translate this into something I could get my arms around,  I assumed in the heating season that the system would run 12 hrs per day (have no idea what the normal range is). So 12 x 0.218 = 2.6 KWH per day. With the KWH rate in my area at around 14 cents, it would cost around 37 cents a day to operate it 12 hours per day. Doesn't sound like a lot - hope I'm not missing something.



    On another note, given your expertise in this area, do you care to weigh in on my earlier post about whether it was feasible to throttle back the gas powered burner on a 154,000 mbtu unit by about 16% and not lose, but possibly even gain efficiency ?



    Thanks for the input !
    jcb
    · ·
  • SteamheadSteamhead Posts: 9,102Member ✭✭✭
    Answers

    That electricity cost sounds right. I haven't put a meter on an atmospheric gas train, but it would cost something to run that too. What you'd end up paying is the difference between the two.



    As far as down-firing, as long as you don't get the stack temperature too low or otherwise cause poor combustion, you should be OK. Whoever does the work MUST test with a digital combustion analyzer to be sure of this.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    · ·
  • jcbjcb Posts: 13Member
    Gas Powered Boiler Down-Sizing

    Steamhead,



     Thanks for your comments on downsizing. Unfortunately, they seem to indicate that it is rather difficult to determine what can be achieved until after the unit is installed. While I was hoping the results would be more predicable ahead of time, I can appreciate the unknowns that may arise with any specific installation.



      The problem in this situation is that the 154,000 gas powered unit seems significantly  more than what is needed to satisfy the EDR plus a pick-up.factor. If for whatever reason it can't be throttled back to get a closer match, I fear the possible result could be short cycling and even a loss of efficiency.. I  get the feeling that your experience indicates that 15/16 % may be a "bridge to far". But on the surface that seems like what may be needed to optimize the system.



      Please understand that I am a non-professional who may well be missing the big picture and asking the wrong questions. I was hopeful from an efficiency point of view that a gas powered wet boiler may be the way to go, but now I'm not so sure. Despite my questions, I'm also in the end a believer in the KISS principle. Presently there seems to be too many things that aren't so simple.



    Thanks again for the input - I need to sleep on it before making any suggestions to my relative.
    jcb
    · ·
  • SteamheadSteamhead Posts: 9,102Member ✭✭✭
    edited July 2014
    You might also look at

    a Utica SFE-4xxx boiler. This one has been offered in various firing rates from 1 GPH/140,000 BTUH input, to 1.5 GPH/210,000 BTUH input. Columbia sells the same boiler as the CSFE-4xxx. The current offering is at 1.25 GPH/175,000 BTUH input, which has a minimal AFUE rating- 82%. But when it was offered at 1 GPH, its AFUE was 85%, and this is how we still sell them.



    At 1 GPH, this boiler was rated 377 square feet EDR. That would be a much closer match for your system.



    Here's one of our Columbia installs along with a couple Intrepids. All have Carlin EZ-Gas burners. Note that the Columbia that got replaced with an Intrepid was being run at its maximum firing rate, which worked the cast-iron heat transfer surface much harder. That and a leaky return that we replaced some years ago is what killed it.



    http://www.heatinghelp.com/forum-thread/150537/Three-Recent-Steamers
    Post edited by Steamhead on
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    · ·
  • jcbjcb Posts: 13Member
    Gas Conversion Boiler Options

    Steamhead,



    Just read your post. Thanks very much for taking the time to suggest several possible options. As a novice in this area, it will take me a bit to digest these, and as always I'll probably come up with a few questions that I hope are relevant.



    Thanks Again,!



    And I welcome anyone else to put in their two cents, especially those who have done a conversion struggled with similar issues.
    jcb
    · ·
  • jcbjcb Posts: 13Member
    Gas Powered Boiler Options

    Steamhead,



    The first part of your last post lists a number of what seems to be oil fired boilers.  Are these  models now being offered with a powered gas option ?  In particular I was looking at the Columbia w/Carlin burner installation that is shown in your photos. I looked at the Columbia website and I can't find any specs on the CSFE series when fired with gas. Hopefully they have done the testing but have not updated their product catalogs ?



     In any case, my relative wants to convert to gas. While atmospheric units would be OK with him, it's just exploring the possibility of increased efficiency that has made me look at the gas powered options. Do you know if Columbia offers gas powered units in sizes less than Slant Fin's 154,000 unit ? Perhaps that's the one you mention as a better match at 377 sq.ft. EDR , but the 1 GPH that prefaced that comment made me uncertain whether it had been rated for a gas conversion. If it has, that may be a better choice than the larger Slent Fin, but some AFUE specs for that configuration would be needed.



    Thanks Again
    jcb
    · ·
  • jcbjcb Posts: 13Member
    My Apologies To Icesailor & RobG

    I apologize for somehow missing your earlier posts. Not sure how that happened but I think it has to do with carelessness combined with aging. In any case, thanks for the input.



    The thread has moved along quite a bit. 



    To Icesailor, I found your analogy regarding the combustion process pretty good. I'm prone to analogies myself,  but they are usually less thought out. In any case, seems to me that getting your face down into the nitty-gritty of it by taking measurements is a really good thing. Makes you appreciate what you are really trying to accomplish.



    And to RobG - Yeah, disappointing that those quoting on the install may not list the specifics. While including that may mean something to you and me,  to 99% of the clients it would likely just fly over their heads to be ignored (unfortunate). So I'll cut the contractors a little slack on this.  But it should be forthcoming on request and if it doesn't, you've got to wonder.



    Thanks again to both of you !
    jcb
    · ·
  • SteamheadSteamhead Posts: 9,102Member ✭✭✭
    edited July 2014
    At least in the Columbia versions

    they are available with Carlin EZ-Gas burners. We get them that way from the local Columbia supply house. The Columbia we installed in that thread I linked to arrived on the delivery truck with the gas burner. Not sure what else I can say to further underline the point.



    Looks like some of these web sites need to be updated.



    I'm not sure why these boilers have been re-rated so much. Perhaps they became too expensive per square foot of radiation capacity for some people if you had to buy them with one more section. But we're all about efficiency so we always use the lower capacity for a given size boiler.



    The Columbia brochure showing the most efficient ratings is here:



    http://columbiaheating.com/certificates/brochure%20CSFE%209-18-09.pdf



    Currently, to get this configuration, we have to order the current designation (CSFE-4125S in your case) and then reset it to the lower firing rate (1 GPH or 140,000 BTU per hour in your case). The difference in stack temperature is quite noticeable.
    Post edited by Steamhead on
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    · ·
  • vaporvacvaporvac Posts: 1,004Member ✭✭✭
    My experience...

    First off, I'm a home owner like yourself, but I spent over two years studying every iteration of boiler/burner combos before settling on my install. With the help of basically every regular on this site, I designed an amazing system and installed most of it, with the exception of the burners which require a combustion analyzer and someone who knows how to use it. I went with twinned Slantfin TR50s Intrepids, which is obviously not applicable to you, but at one time I had considered the TR30 in a 70/30 split. It's definitely rated for gas. (FYI, the TR30H is for Hotwater, NOT steam.)



    The technical lit on SF's site does not really cover the gas install at all. You have to call their tech department and they'll email you all the particulars. They're fabulously helpful, even to homeowners. They may recommend a few burners or the pros here can tell you what they use. I then called the burner manufacturer's tech departments to find out which particular burner would work with my chosen boiler size.

    These burners are designed to be dialed in to the exact firing requirements. It's not a jacked-up fix; so long as it's approved for the TR30 the firing range should be good. For example, my two boilers have two different firing rates to match my attached edr. When I add back in some rads, we'll change it to accommodate them. I have the Riello G400 which is easily changed with differing orifice plates to fire between 170-400Kbtus!!! That's a pretty big spread.

    Just to reiterate,This isn't a guessing game. The burner manu will tell you what burner will go with which boiler. The firing rate is then determined by the EDR. A combustion analyzer is used to dial in the correct ratio and then you'll have your efficiency rating.

    BTW, I also believe their AFUE numbers are for oil. It's always slightly lower for gas, but it doesn't reflect the whole efficiency story .



    I do not find my two power burners any noisier than my atmospheric boiler, but that differs depending on the brand. I've read here that the EZGas is noisier, but can be fitted with baffles? I'm sure the pros are more knowledgable, but I did check the dcb of all my options. The electricity usage is neither here nor there. The savings from a set-up like this is big. I can't imagine a boiler this size would require a larger gas main.

    Lastly, many manufactures (like SF) do not list their oil boilers as gas approved even though they are. You have to call.

    Feel free to look up my many posts. It was clear a wet-based power burner was the way to go, not just for efficiency, but for longevity as well.
    Two-pipe Trane vaporvacuum system; 1466 edr
    Twinned, staged Slantfin TR50s piped into 4" header with Riello G400 burners; 240K lead, 200K lag Btus. Controlled by Taco Relay and Honeywell RTH6580WF
    · ·
  • jcbjcb Posts: 13Member
    Your Experience

    Vaporvac,



    Sorry it took a bit to respond to your post - I was occupied in trying to keep the family's auto fleet on the road !



     Personal experience like yours is the kind of input that I most appreciate. It's obvious that you have taken your involvement to a level well beyond that of the common homeowner  and are realizing the benefits as a result. Congratulations !

     

    When I got involved in my relative's situation a little over a month ago, I was under the impression that gas steam boilers were locked in at 80-81% AFUE. My own home has a one pipe steam system with a gas fired 175,000 mbtu Burnham Series 4 that I had installed almost 34 years ago. I knew nothing about such things back then and just wanted to get off the old 1930 boiler that may originally have been coal fired and then converted to oil.  I only had one contractor give me a quote and the price seemed right.  I went with him even though now looking back I'm almost certain that, while he may have counted the number of radiators, he never computed the EDR.



    But I really shouldn't complain, as the unit is still on line and the savings from switching fuels was quite dramatic. About 6-7 years ago I was concerned about the rising cost of gas and looked at this forum for possible ways to improve my efficiency. I learned about how to compute my EDR and found that my boiler was perhaps 10-20% larger than what I needed. I recall calling Burnham to find out if there was a way to improve my boilers efficiency by reducing the btu input, perhaps by blocking off a row or two of burners. He said I'd likely crack the metal because of uneven firing, and of course that made sense. I asked about new boiler efficiency, and he said nothing had changed in steam boiler technology, and I'd get the same results with a new one (unless perhaps a smaller unit was a better match).



    So I decided to go with mine unless something bad happened (I hope the beast down in the basement doesn't hear me typing). So now I'm back into it, and in fact it does look like there is a technological shift with the powered gas burners firing a boiler of more efficient design, such as a wet base one. So generally I don't need to be sold on those benefits. Despite that, I still have these lingering concerns that when it comes to satisfying small applications needing perhaps only 300 sq.ft of steam, the powered gas options seem to come in at 375 sg. ft., even after the powered burner firing rate is reduced when matched with a larger boiler that was originally designed as oil fired. I know the system will work, but I'm just hung up on the degree of the EDR mismatch.



    Anyway, in the end I'll probably get over this and tell my relative this is a viable way to go. However, there is a side issue that could complicate things significantly. If the gas input gets too large, the local utility may require a larger main to the house. I'm not certain of this, but I suspect the utility uses the data plate input on the boiler to compute this, even though the actual input will be less after install.  I know you said this was unlikely, but a neighbor in his development had to have this done when he had a 159,000 atmospheric boiler installed a year or so ago.



    Again, thanks for the input !
    jcb
    · ·
  • jcbjcb Posts: 13Member
    Columbia Possibilities

    Steamhead,



    Sorry that it took awhile, but I just had a chance to look at your last post in more depth. As I noted previously, it doesn't take much to confuse me, so I stumbled around for awhile before the fog began to clear a bit. But I do have a few comments/questions :



    So it seems that the Columbia CSFE-4125s is another possible option along with the Slant Fin TR-30. What confused me at first was why you chose the 4125s with an efficiency rating of 82.5% (at 1.25 gph),   when the chart shows a 1 gph CSFHE - 4100s that produces 377 sq.ft. and has an AFUE rating of 85%  and an energy star rating.. The fog lifted and I realized that in effect you had achieved the same thing by using 140,000 of powered gas. I then found another chart which I guess is more up to date that seems to confirm this:



    http://www.columbiaheating.com/pdf/New_2012_CSFH_IV_sell_sheet.pdf



    So I'm trying to read between the lines when comparing the Columbia to the Slant Fin. You seem to have no problem with saying that you can power the Columbia with 140,000, while you didn't commit in a prior post to a more definitive lower input  when discussing the Slant Fin. Now I know that at the end of the day either gas burner's input will be tweaked to get acceptable test results. But it seems important in my relatives installation to have a harder (anticipated ?) input number with the Slant Fin ahead of time.



    In his situation a larger gas main to the house may be required if the utility company calculates that the new unit size warrants it.  This would complicate the installation significantly.. I don't know how the utility computes such things. If they simply use the oil fired  btu input that shows on the units data plate, that will almost certainly dictate a larger feed. Note that the data plate may indicate 154,000 for the Slant Fin and a whopping 175,000 for the Columbia 4125. Another person in his neighborhood had to increase the main when he had a 159,000 atmoshperic unit installed several years ago. I'm sure in his situation the utility company would have used that number, because there is no significant tweaking. However, when it's known ahead of time that either of these two powered burner units will come in somewhere around 140,000, that difference may be enough to avoid a larger main. But I don't know if the utility considers this.



    Your input based on experience would be greatly appreciated on how utilities handle such situations.



    One final question -  Given the two different boiler designs between the Columbia and the Slant Fin, do you have a preference in terms of efficiency and/or construction ?



    Thanks Again !
    jcb
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  • SteamheadSteamhead Posts: 9,102Member ✭✭✭
    The answer is simple

    At the moment, I have both charts for the Columbia. For the Intrepid I only have the one chart. Slant/Fin did change their Intrepid chart recently but their rated efficiencies went UP with the change, rather than down as with the Columbia. Bottom line is, we always work from the chart with the best efficiency.



    In many cases the incoming gas service and meter are fine, especially on smaller jobs, but we have to check out each one to be sure. If upgrades are needed that's the utility's problem, and around here they take their sweet time getting to them. If this turns out to be an issue, you can always install a new boiler with the oil burner first, and change it over to gas when the service upgrade is done.



    We choose our boilers based on how close they are to the load, how well they will fit the available space and how well they are supported.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    · ·
  • RobGRobG Posts: 1,446Member ✭✭✭
    Gas

    Do you know what the in home gas piping sizes and attached loads are? I can give you an ESTIMATE to see if the piping will work. Usually the piping to the house is not the problem, it's the piping in the home that needs up-sizing (if it needs up-sizing at all).



    Rob   
    · ·
  • jcbjcb Posts: 13Member
    Gas Piping Size

    RobG, 



     Unfortunately I don't know the exact line sizes. I spoke with my relative and based on his description, it appears his meter is piped exactly as mine. I don't believe it is worthwhile to describe that to you because there is another complicating factor that may make this somewhat irrelevant.  I hadn't mentioned this previously because it makes the situation too involved. In this case the gas line from the utility feeds both his house and also his next door neighbor's. It comes into his basement at a larger size and then reduces to feed both his meter and then thru the wall to the neighbor's meter.



       I would have to assume that the utility has to combine both homes to determine whether a new main is needed. The neighbor is known to have already converted to gas heating, and likely also uses gas for the water heater and stove - same as with my relative. He has a gas clothes dryer and possibly the neighbor also does. He has added up the total load for his home and comes up with 299,000 which includes 154,000 btus for a Slant Fin boiler. I assume that this is what the boilers data plate would say whether gas or oil fired, and appears what the utility company will use for computations  no matter what  a contractor claims the firing rate will be downsized to in the end.



      As to is actual piping size, my relative eyeballed the incoming line as 2" OD. Given the pipes sidewall thickness, this probably translates into a 1 /3/4" pipe size, 1 7/8" at best.. If you would like to venture an estimate of how many btus a pipe of that size would supply, it should give many of us some perspective. As to the total load for a given home, I would have to assume that the utility must assume that not every appliance is being used at the same time and therefore apply a reduction % of some amount.  If someone has a clue as to what this reduction factor is, this would also be beneficial to know.



    Thanks for your input and the offer to take the time to do some estimating !
    jcb
    · ·
  • jcbjcb Posts: 13Member
    Probably Time To End This Thread, At Least For Now !

      Since starting this thread I have been feeding my relative pieces of info on what is being discussed as to potential boiler options. Unfortunately, I have never been able to get him to directly follow the thread to evaluate the input himself

    .

      What has happened that since the thread started he has committed to a newer quote that includes a boiler with a powered gas burner . While I can't say that in the end that I wouldn't have made the same choice, I was beginning to lean more toward my instinct of following the KISS principle. Just seemed to me that given the powered gas combinations that were discussed, there were too many unknowns with throttling back to match a low heating requirement. No matter how I figured it, in the end he would still have 20-30%  more capacity than his EDR required. Will the higher efficiency rating overcome this ? - possibly.  I'll be the first to admit that I still may not be seeing this correctly.



      So seems best just to sit back for now and see how things play out. Hopefully the installation will go smoothly. I just hope that some of the side issues do not get in the way. I will say that the contractor of choice is competent and well respected, so I don't expect any problems on that end. As has been noted many times on this forum, the installer is just as important as the equipment, and I believe that to be true. It will obviously take getting into the heating season before the system performance can be evaluated. If there are any new developments prior to that, I will post them as they occur.



    I'd like to thank all of you that posted your input on this thread. I certainly have learned a good deal if my own "beast in the basement" should ever decide to act up !
    jcb
    · ·
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