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attaching building heat load

Grumpy_Guy Member Posts: 17
Hi, first post here.

I'm looking at replacing my Dragons in increments and to upgrade the system in general. Currently I do not like the advise from my local contractor. (seems to know less then I do and that ain't much)

My building is a mix of commercial (retail) and residential (6: 1 bedroom units about 500sq each) in three sections, front section is the largest with the biggest dragon for heat and two babys for domestic hot water. 3 levels not including the basement and a footprint of 32X50. The middle and back section (32X30) are serviced by a smaller dragon and 1 baby for domestic back is 2 levels on grade and the middle is 1 level on grade (32X40).

The middle is actually serviced by both sides, some rads heated from the back some from the front, domestic from front. Unlike my contractor I did a heat loss and found the back surprisingly sized proper probably by mistake more then intentional (if middle section is totally added to it), and of course the front way over-sized. (age of units approximately 30yrs Rudd tube) The front is over-sized enough that it could take on the load of the back and possible not break a sweat.

My question is what size of pipe would be acceptable for doing this, remove back dragon and feed from front. The middle building has a 1.25" pipe running from end to end, all that would be needed to cut-into the front system is another 30' and a couple of angles.

My future goals are to replace the front boiler with multiple boilers and an indirect hot water.

Building is late 1800's and mid 50's as a guess. (depending on what section we are talking about) Total sq is < 9000ft (Northern Ontario)

Thanks in advance for any insight.


  • dragons

    is this steam or hot water?--nbc
  • Grumpy_Guy
    Grumpy_Guy Member Posts: 17

    Sorry, it is hot water. Guessing the front boiler used to be steam at

    one time considering the size of the pipes near it. (4" but looks like

    5") pipes currently attached to boiler are 2" and the return and supply

    are different pipes.(rads are the loop to each pipe) As far as I can

    tell all loads are piped separately from the basement.
  • icesailor
    icesailor Member Posts: 7,265

    More likely, it was gravity converted to forced hot water with a circulator than steam. If the pipe sizes to the radiators are the same size on both sides of the radiators, it was probably gravity hot water origonally.
  • Grumpy_Guy
    Grumpy_Guy Member Posts: 17
    More info

    Both Boilers are Rudd multi tube

    Front is 567000 with a calculated heat loss using FloPro Designer of 340000 (non insulated walls double hung windows) pump is Armstrong 1/6 flow on heat only

    Back is 217000 (173000) with a calculated heat load of  160000 (includes middle section uninsulated but will be by January) pump is Armstrong 1/12 constant flow (probable because of pipe being so close to uninsulated wall. This one also has a problem with back-flow (draft)

    And yes insulation is happening now, but it is a big place. (Have only owned since may 2010)
  • Grumpy_Guy
    Grumpy_Guy Member Posts: 17

    Thanks icesailor, my knowledge is really limited. (contractor suggested steam)
  • meplumber
    meplumber Member Posts: 678
    Sounds Like you need to find a better contractor.

    If your contractor couldn't tell the difference between a gravity hot water system and an old steam system then you need to replace him.

    Better to cut your ties now than after he has done a lot of shotty work to this old building.

    Look around for a true professional.
  • icesailor
    icesailor Member Posts: 7,265
    Building load:

    I ask, how did you come to 567,000 BTU's with a calculated FloPro Designer of 340,000 BTU? Is that 567,000 the rating of a boiler serving that area of the building and the 340,000 is the calculated load of what is there?

    Same with the other part?

    What factors are you using for the walls and ceilings? Uninsulated or insulated?

    I'm not familiar with FloPro Designer. I didn't know it did heat loss calculations. I have it but I've never tried to use it.
  • Grumpy_Guy
    Grumpy_Guy Member Posts: 17
    Sounds Like you need to find a better contractor.

    If that truly was an option I would have done it already instead of being here getting educated. Nothing wrong with learning new things but I have done enough in my life time to last into the next:)

    In my community it is hard to find true professionals, no I do not mean a guy with a license but a person/company that truly takes pride and stands behind what they do. So what I have done is hired the best plumber I know, gas fitter and pipe fitter, three different trade professionals. The plumber knows the most but also rely heavily on an uncle in Toronto who specializes in boilers. The pipe fitter is a pipe fitter and knows little about hydronic heat but he is the fastest and best person for new pipe or retrofit. The plumber is not gas certified so he can only do the plumbing, and the gas fitter is a true professional but not in hydronics.

    It would take a very long post to explain my position on contractors, but just believe that I have tried many in many fields with most failing some of the simplest task.

    Oh as a side note I used to be a gas fitter too, but that was a while ago and I have not kept up. So what I do with any large job that I have limited knowledge in is research, helps limit the BS factor.
  • icesailor
    icesailor Member Posts: 7,265


    I guess you are posting uninsulated loss figures. And I guess you just bought the building. You are probably on a very tight budget.

    However, if you are at all considering replacing these boilers, I would seriously consider adding the insulation to the equation before you install than after. If you size the boilers with a uninsulated building, the boilers will be way oversized for the insulated load.

    For example. If you take a 10'x10' wall section of a frame wall with 2"x4" studs, plywood sheathing, tar paper, shingles and 1/2" gypsum board. it will loose .25 BTU's per square ft per difference of outside temp and inside temp. Or, 1750 BTU's per hour = 3' #30 Slant Fin baseboard. If you take the same wall and add 3.5" of fiberglass insulation, the factor drops to 0.07. That equals 490 BTU's per hour or less than 1' of #15 Slant Fin baseboard.

    If your front part needed 335,000 BTU's of heat, that comes out to close to 560' of #30 Slant Fin. Reduce that loss with insulation and you will pay for the extra boiler in a flash. Do the math. This is just using a quick number off the top of my head. That is why a correctly done heat loss calculation is the best money you will spend. Anyone who can do one woould be proud to do it for you. It's easy and you know what the $ you are doing when you do it. If someone can't give you a printed out HL calculation, and they won't do one, wish them well.

    When I first started doing my own, I was afraid I wouldn't have enough. It has never happened. It doesn't take much to heat it.

    You can downsize a oil boiler rather easier but gas is another project. You really aren't supposed to do it because it violates the UL and Canadian Standards listings.

    Spend your money as you see fit but if you insulate now instead of later, you will put money in your pocket.

  • Grumpy_Guy
    Grumpy_Guy Member Posts: 17

    icesailor you are right on so many points, and I do agree and understand that there is more bang for the buck with insulation. The problem is I cannot afford to do a complete retro fit at this time. Building is double layer brick balloon framing, in the downtown core so it is attached at the front for 35' and the back for 32' leaving about 45' on one side with a 10' gap between buildings. The other side is open for the whole 110' of course the front is mostly windows. Back of the building has had work and it is unknown if foam board was put up before the steel siding on the main building. Back building is insulated to some degree.

    As for budget, well it has been thrown out the door just doing fire upgrades, and store fronts, and two units renovated. ($170,000)

    That is why I'm looking at moving to one existing boiler now, and three 200000 btu boilers later. (firing at different stages as demand calls for and rotating order) As I do repairs I upgrade electrical, plumbing and insulation, yes I understand at a later date I will be over-sized for demand but by having multiple condesing units that should not be to much of a concern. Also the priority for a domestic hot water will only need 1 boiler while the other two continue heating loads.

    If I can eliminate the small boiler in the back building I will save on efficiency and the fact I do not need to build a boiler room. Also the blow-back will be less of a concern with no gas appliance there.
  • icesailor
    icesailor Member Posts: 7,265
    edited November 2010
    Reno loads:

    Renovations are always like that. What you start out wanting to do, always get changed.

    Three boilers are the way to go though. I have a place where I did this. A control to run one or all boilers as needed and they change sequences. It's too bad you can't find someone with a pragmatic approach to this problem and develop a long term approach to solution. It would be an interesting project.

    The heating mechanicals always take a back seat to everything else. Out of site, out of mind.

    If it is possible, a clever, imaginative type may be able to see a way to tie these two systems together for now. The smaller boiler can be set to run and take the load of the whole building with an assist from the larger one. As the load goes up, the larger one takes more and more of the load. It's a piping and control issue. If you have the resources there, it is just up to someone to figure out how to use them effectively.
  • Grumpy_Guy
    Grumpy_Guy Member Posts: 17
    Reno loads:

    Before buying the building I was a commercial tenant, hence why I bought the building was to renovate were the owner would not. Doing the store fronts were not schedule until next year, but after two out of 4 windows being broke I figured why not now.$$$

    It's too bad you can't find someone with a pragmatic approach to this

    problem and develop a long term approach to solution

    One of the reasons I'm here, looking for guidance from people with experience and desire for hydronic solutions. I may try connecting the back with the existing 1.25" pipe from the front boiler as a test, after all I can separate them with shut off valves. I guess I need a zone pump to tell the front boiler when the back needs heat.
  • dragonsunited!

    sounds like an interesting and worthwhile project. as you say, you can always undo any changes, or valve them off.

    why not post a diagram of the building layout, and the piping to make it easier to visualize what changes could be made. as far as controlling the dragons, probably a control from tekmar will keep them firing right. as far as i can see the pumping may have to be triggered by the call for heat, and the burner controlled by water-loop temperature. if the building is picturesque, post a picture of that as well.

    if you have some fun things to do in your area [fishing, curling], maybe one of the experts could be tempted to pay a visit and give an opinion!--nbc
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