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Two Replacement Boiler Questions

ajc Member Posts: 5
The point about the standing pilot is dead on. An electric ignition system should only be used if an indirect water heater is used with the boiler. This way your boiler would run all year. An electric ignition boiler in a damp cellar will turn to a rusted mess faster than you can imagine. I doubt that you will find a millivolt system, most likely it will be a 24 volt system that needs power. Also be very careful with the vent damper. It should be left open because with a smaller boiler and a closed vent damper, your chimney will cool in the winter during off cycles. When the boiler fires it will cause condensation on startup and ruin your chimney liner real quickly. The best route is to power vent or line your chimney with a metal. liner.


  • CK_3
    CK_3 Member Posts: 4
    Replacement Boiler questions

    Hi, I'm needing to replace a steam heat boiler (radiators) for a 1750 sq ft one-story home in upstate NY and am looking at quotes from different contractors. Two questions:

    1) One contractor recommends a standing pilot instead of intermittent electric ignition, saying that the benefits of slightly higher fuel efficiency are outweighed by the fact that the area around the pilot will be kept dry in the non-heating months. Is this a significant enough advantage to merit getting a standing pilot boiler? The basement does not flood but it can certainly be humid in the summer.

    2) Contractors differ somewhat significantly on calculating sq ft of radiation on the radiators, which affects the choice of boiler size. We don't want to oversize or undersize. Each contractor seems to be referring to a different multiplier chart. I'll post my calculations here and hope that someone will be able to confirm a square footage. Heat loss in the basement seems to be minimal (old asbestos insulation still in place, attic and walls recently insulated), and the one-story house might mean somewhat less overall loss.

    All radiators are 38 inches high. The tubes are 34 inches from top to bottom and 4 inches off the floor. Each section of tube is 2.25 inches wide and 7.5 inches deep. Each section forms a loop. If I thread a cloth measuring tape around an individual pipe, it has 8 inches of girth. There are 9 radiators in the house, and a total of 67 sections. If I use girth times [(width plus depth) times two] for the surface area, I get 4.61 sq ft per section (308 for the whole house). One contractor uses a multiplier of 3.67 per section (246 sq ft for the whole house). The boilers we're looking at are at 254 and 317 levels. What do you think?
  • Gene_2
    Gene_2 Member Posts: 59

    What is your location? We are located in the Capital District. We would be more than willing (and able) to help you.

    Darin - Comfortable Home Technologies
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Couple of Thoughts

    1. Standing Pilot: Point about condensation is well taken and is a subject of sometimes intense debate... It may cost you more in energy than you realize because use of a standing pilot may preclude you from using a vent damper. If you do have a standing pilot and a vent damper there is a small punch out button designed to vent those pilot products of combustion.... A slight defeating of the purpose.

    I will leave it to others who handle the service side of these (and see the insides after years of such operation). Happily will I defer to their opinions and experience.

    One really good feature is that the standing pilot and an assumed milivolt system, will allow you to have heating during a power outage. Not sure if that is a big deal where you live, but it is an advantage.

    Radiator sizing: Good info, not enough time to compare. Suggest you get a copy on-line of Burnham Boiler's Heating Helper download. It has a nice chart of common radiator makes. Who knows, you may come up with a third number-

    Question to ask the high-estimated contractor: Did they add in anything for piping? Can you ask both to see their work and tables on which they made their assumptions?

    A photo of a typical radiator may help also. The differences are wide enough to ask.

    And by the way- you are to be commended for preserving your steam system. Stick around here to get lots of info as to how to do it right. We hope your contractors lurk or participate here also...

    My $0.02

  • Brad White_9
    Brad White_9 Member Posts: 2,440
    I second that

    Give Darin and Mark a call.
  • CK_3
    CK_3 Member Posts: 4

    We're near Seneca Lake, and near the top of a hill (or glacial drumlin, if you prefer) so the basement moisture issue is about humidity. The sq ft issue is of more concern.
  • CK_3
    CK_3 Member Posts: 4

    Thanks, Brad! I downloaded Burham's htghelper.pdf and our radiators are "obsolete cast iron radiators" of the 7.5 wide, 38 inch high variety, which uses a sq ft multiplier of 4 (a little under my tape measure estimates). 4x67 is 268, so that suggests we should get the boiler rated *317*, not the one rated *254*. Those figures take the other piping into consideration, it says.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    Yes, 2-column 48" high radiators do have 4 square feet of EDR per section.

    As to boiler sizing, you and your contractors are definitely on the right track sizing via the radiation. The square foot ratings of steam boiler do consider "typical" piping.

    As long as the system is intact, e.g. no removed radiators, it seems hard for me to believe that 5% undersizing would be a problem as the piping sounds to be reasonably insulated.
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Don't forget the number of tubes (\"columns\")

    in each section not to mention the number of sections, of course... Some manufacturers had 3 tubes in under 8 inches, albeit smaller tubes... but I suspect you know well what you have!

    The boiler capacity data in EDR does allow for piping and should clearly say so which I believe you have discovered. You may be right on the edge in that if your piping is well insulated (as it should be) you just may get by with the 254... if in doubt, get other opinions. Not to confuse you but just so you know. The "overage" for piping and pick-up may be conservative....

    This is almost fun is it not?

    I have to emphasize the importance of the near-boiler piping, how critical this is to performance, quality of steam, efficiency, speed of heating and how quiet it will be... nearly silent if done right. This is why you should hang out here a bit and ask more questions....
  • the new boiler

    Brad is 100% correct about the new boiler near pipings as the pipings itself become part of boiler... Another thing to look for is ur main venting , without it or not working, system won't work as whole... If were you, buy a book from this website " You got steam" . The book will help you understand the whole aspect of steam heating system and I credited you for keeping it... Keeps them questions coming..
  • CK_3
    CK_3 Member Posts: 4

    Thanks, everyone, for your thoughts and suggestions! I think I'm better prepared to approach the contractors who have given quotes.
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