Page 1 of 4 1234 LastLast
Results 1 to 13 of 42

Thread: sizing boiler?

  1. #1
    Join Date
    Aug 2002
    Posts
    391
    When installing a new hot water boiler, what is more important when selecting size. Heat loss of the house or the btu output of the existing base board? Will assuming a base board out put of 600 btu per foot x total lenth of basebord decide the boiler btu output?
    The obvious is obvious

  2. #2
    Join Date
    Apr 2003
    Location
    Eugene, Oregon
    Posts
    1,209
    First order is load calculation of the home, then sizing existing baseboard capacities. You then need to decide if you have enough baseboard to get the job done. Then size the boiler accordingly.
    Proud supporter of Springfield Millers and Oregon Ducks.

  3. #3
    Join Date
    Sep 2004
    Posts
    654
    Never base it on existing baseboard capacity. What if the HO wants to add a room on the house? Or heat the garage, or whatever...that would require changing out the boiler then.

    Do a heat loss calc and go one size larger. Good rule of thumb that pays future dividends.


  4. #4
    Join Date
    Apr 2003
    Location
    Eugene, Oregon
    Posts
    1,209
    The only time you should use your thumb is to hold onto something, and never assume either.
    Proud supporter of Springfield Millers and Oregon Ducks.

  5. #5
    Join Date
    Jan 2002
    Location
    New Hampshire
    Posts
    1,285

    Do NOT go one size larger

    That shortens the life of the boiler, costs more to buy, and costs more to run.

    Size it to the heat loss. Period.

    http://www.slantfin.com/he2/

    Noel

  6. #6
    Join Date
    Sep 2004
    Posts
    654
    Originally posted by millerman
    The only time you should use your thumb is to hold onto something, and never assume either.
    Oversizing slightly is very applicable, I see it every day and it flatout works. I've seen too many times where a 3000 sq ft house has maybe 100,000 btu of heat loss so a 100k btu boiler is installed. In no time, the boiler is half dead and sometimes, can't heat the house since the heat loss is more than the calcs came up with. Realize, heat calcs are typically done without even seeing the actual construction, done well before a single nail is hammered, and assumes correct installation. We all know how that works out.

    Tell the HO he needs to buy a new boiler if he wants to add just a smidgen more heat somewhere (or put on an addition) and you won't be in business long.


  7. #7
    Join Date
    Jan 2002
    Location
    New Hampshire
    Posts
    1,285

    I'm not going out of business soon

    AND I stand by what I said.

    I spend a major portion of my day explaining to homeowners of contractor installed equipment why the thing short cycles so badly, why condensation is running out of the chimney cleanout, and why controls die so young.

    You do what you want to, in your new construction jobs.

    Noel

  8. #8
    Join Date
    Apr 2003
    Location
    Eugene, Oregon
    Posts
    1,209
    "Kick it up notch BAM" Go Emeril
    Proud supporter of Springfield Millers and Oregon Ducks.

  9. #9
    Join Date
    Jan 2002
    Location
    New Hampshire
    Posts
    1,285

    It's no different than furnaces....


  10. #10
    Join Date
    Aug 2002
    Posts
    391
    This house is built out with no additions in it's future. I can find no real technical information on which way to go.
    The obvious is obvious

  11. #11
    Join Date
    Jan 2002
    Location
    New Hampshire
    Posts
    1,285

    You're not trying hard enough

    I'll post it again for you.

    Here it is.

    http://www.slantfin.com/he2/

    Noel

  12. #12
    Join Date
    Aug 2002
    Posts
    391
    Just to be clear this is an oil fired hot water boiler. I think some of the coments here are for gas.
    The obvious is obvious

  13. #13
    Join Date
    Jan 2002
    Location
    New Hampshire
    Posts
    1,285

    Which comments?

    Flue gas condensation occurs worse (gummy mess that's flammable) on oil than on gas.

    Noel

Page 1 of 4 1234 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event