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Small boilers?

Aaron Gibson
Aaron Gibson Member Posts: 15
in THE MAIN WALL
I'm in the process of renovating a small (540sq ft) camp into a four season residence for myself. I've got a few panel radiators from a supplier for almost free and I would like to use them in the house. Since I'm only dealing with 540sq ft , my heat load is around 15,000 BTU. Should I use a direct vent water heater(not my favorite idea) or is there a small wall hung MOD/CON that I havent heard about? I suppose I could just
buy an Empire or a Rinnai, but that would really stink.

Since I'm self employed and poor, price is an issue, but my labor is free.

This forum is great!

Comments

  • ALH_4
    ALH_4 Member Posts: 1,790
    Bradford White

    Bradford White makes a combination water heater that would work.
  • Aaron Gibson
    Aaron Gibson Member Posts: 15


    I did see those,actually. I was trying to find something a bit more efficient and maybe electronic ignition. State has a similiar tank with an HSI that looks pretty decent and its even got side tappings for space heating.If I could find a more affordable version of the Polaris tank, I would be all over it.

    Thanks,
    Aaron
  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    Triangle Tube has a combo unit too

    Modulating burner and nice controls, it looks like.

    Boilerpro

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Aaron Gibson
    Aaron Gibson Member Posts: 15


    Yes, I did check the Prestige out, but as I recall it modulates from 15,000 - 150,000 BTU. If my load is 15,000 BTU @ -20 , then the boiler will never really modulate which really defeats the purpose of spending the money. I'm starting to think that a wall hung Takagi piped as a closed system might be the trick? I wonder how long it would last?

    Aaron
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    I understand "self-employed and poor" quite well. Sometimes though you have to scrimp in some places to get something truly appropriate in others...

    If you want high efficiency, safety and DHW in a single unit search out "combi-boilers" that are condensing/modulating. Surely at least a few are available in the U.S.

    If you want lowest possible cost, a "water heater" with appropriate controls and safeties will do the job at the expense of efficiency. Please don't however use such for both space heating and DHW! I know that the Polaris is a high efficiency "water heater" but I don't believe it's designed to separate space heating from DHW like the Bradford White model suggested.

    For comfort and efficiency consider TRVs on your panel rads. Really not difficult to make a sweet little system using a "water heater". You'll take an efficiency hit, but comfort/versatility will be high and you'll have the benefit of a buffer...
  • ALH_4
    ALH_4 Member Posts: 1,790
    heat load

    The load is just so small, and that even seems relatively high for that floor area. Is it log construction?

    I know of nothing that modulates less than 15MBH, and that is the "design" load. You will probably be nowhere near that 90% of the time. Keep in mind, the less fuel you burn, the less high efficiency products will save you and the less the return on investment will be. That is why I suggested a tank-type water heater. It has some mass to mitigate cycling and also has a dual use.
  • Aaron Gibson
    Aaron Gibson Member Posts: 15


    I guess I should have mentioned that I'm a poor self employed master plumber when I first posted. I see a lot of Home owners buying water heaters for both heat and domestic without a heat exchanger all the time. I think Cross connections are a real issue with online companies selling "direct".Fortunately, I haven't heard of anyone getting sick yet.

    Even if I used an instant water heater as a boiler, I would run it as a closed system since I'm on well water and I'm sure the passages in the heat Ex's are pretty small.

    Maybe I could just use an old cast iron rad with a small hand held torch as a boiler? I'll even put it outside just to be safe :>
  • Dave_4
    Dave_4 Member Posts: 1,405
    Is electric an option?

    If your electric rates aren't too high, you might want to consider a 5KW Thermolec electric boiler - it'ss the perfect size and it modulates.

    http://www.thermolec.com/boilers.htm
  • ALH_4
    ALH_4 Member Posts: 1,790
    electric

    Or a Laing EPR 6. I think these Laing heaters are the coolest thing since sliced bread for small heating loads. (I'm sure we have all tried heating with sliced bread. On second thought, maybe that isnt the best analogy.) They are the whole package and come with lots of control options. I have designed a few systems with these heaters, and have had no problems at all.
  • Aaron Gibson
    Aaron Gibson Member Posts: 15


    Electricty is pretty expensive here (VT). Solar thermal is a possibility if I have a large enough array I guess. Thats another reason why the Polaris tank is so attractive. If I did a two tank system with solar as a pre heat and the polaris as a boost I might have something.

    How about a Tekmar two stage stat running circ from a large thermal storage tank (250 gallon) as H1 and if the temp in the tank drops, then the second stage would kick in and start a circ pumping through a Takagi turning the burner on?

  • Brad White_167
    Brad White_167 Member Posts: 12
    Your Plight

    illustrates what many of us have asked for: Smaller mod-con hydronic boilers.

    Absent hydronics (yes, I know you have the radiators), my choice would be room heaters such as by Monitor or Rinnai.

  • Aaron Gibson
    Aaron Gibson Member Posts: 15


    My big question is why can't the boiler companies make a smaller unit? I'm seeing a trend towards smaller houses here in the NE, so maybe we will see something in the future?

    If I could find a boiler that starts at 5,000 BTU and ramps to
    50,000 ,I would buy it. Rinnai's are nice, but they don't hold water.........
  • [Deleted User]
    [Deleted User] Posts: 0
    Munchkin T50 wall mount...

    50K for space heating, 80K for DHW production and modulation down to around 12,000 minimum.

    Congrats on your licensure.

    ME
  • Aaron Gibson
    Aaron Gibson Member Posts: 15


    Thanks Mark! I've been looking at the Munchkin online and with your glowing endorcement, I'll see what the pricing is like. The Munchy sure is a cute little guy.
    I picked up the install Manual for the Takagi T-Kjr yesterday and read through it last night. Takagi has piping diagrams for use as a heating plant, so maybe its worth a shot for Giggles. My local supplier offered me one for under $600 and a slightly damaged Triangle tube smart tank for almost free. Maybe if I run it as a closed system,The JR will last a bit longer and not plug up.

    So Mark, if I went the Munchkin route, would it be worth doing a blend/buffer tank to get longer run times? As I recall you used an Amtrol tank in reverse and liked it. Care to expand on that for me?

    Thanks guys!

    Aaron

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