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Boiler Selection

jac34jac34 Member Posts: 25
I've been doing quite a bit of research on boilers as I am switching over to propane from oil.
Lochinvar Knight KHL fire tube or the Weil McClain Ultra series 4?

It will be connected to a hot water cast iron radiator system that I'm considering breaking up into 2 zones; right now it's on one. I'm looking to go as green/efficient/smart as possible but want to make sure I'm not missing anything here. I'm no expert and don't no all the little things to consider so any input is appreciated!

Thanks in advance!


  • BrewbeerBrewbeer Member Posts: 509
    Consider doing a room by room heat loss calc and emitter survey. If maximizing efficiency is the primary driver, you will want a system that returns the lowest temp water possible from the radiators to the boiler.
    Hydronics inspired homeowner with self-designed high efficiency low temperature baseboard system and professionally installed mod-con boiler with indirect DHW. My system design thread:
    System Photo:
  • HVACNUTHVACNUT Member Posts: 1,712
    LP in my area is buku $$. Look into the Energy Kinetics Resolute. 90+% efficient oil, and can be converted to gas in the future if you decide to do so.
  • ZmanZman Member Posts: 4,566
    Compare different energy cost in you market by plugging in market prices and efficiency.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • ratioratio Member Posts: 1,768
    What does your installer suggest? As he's the single biggest determining factor of a reliable, efficient install, the ones he's most familiar with will be the best.
  • SeymourCatesSeymourCates Member Posts: 162

    One gallon of propane contains 65% of the energy of 1 gallon of fuel oil. Therefore, the propane cost must also be 65% of the fuel oil cost in order to break even. Even when the additional efficiency of the new propane machine is factored into the equation, I highly doubt that you can breakeven on this conversion when the capital costs are considered.
  • jac34jac34 Member Posts: 25
    Thanks all.

    I hear ya on the propane vs oil but the versatility is what I’m after. We are putting in a standby generator and a propane fireplace insert. Oil can only heat so I’m making the switch over.

    We are able to get into a large neighborhood buying group that gets a nice wholesale discount.

    Sounds like the brand is not crucial?
  • delta Tdelta T Member Posts: 703
    My personal favorite would be the Lochinvar, but it will really depend on what is better supported in your area. Is there someone who really knows Lochinvar boilers to service and install the system? Are parts readily available near you?

    Cast iron radiators can be an ideal match for a condensing boiler, utilizing constant circulation, TRVs on the rads, and an outdoor reset. If you are really looking for the most efficiency out of your system, this is the route I would go. To do this right will mean doing a heat loss calculation, and an emmitter survey to see what the design paramters will be for the pumps and the boiler size. Do not be surprised if the correct boiler is 1/2 to 1/3 the btu input as your current boiler. It will still work (assuming the math is done correctly!).

    More important than the boiler you select is the contractor you select to install it. Will they do all the design work necessary to make the system run well? If not, you will not be happy with the performance, and the boiler (whichever you choose) will not last as long as it should.
  • HenryHenry Member Posts: 848
    Lochinvar or HTP would be good boilers after a heat loss study. Both will condense with cast iron radiation and will be super due to modulation. Maintenance is the big difference between a propane fueled and an oil fired boiler. The propane boiler you can have serviced every second year!
  • jac34jac34 Member Posts: 25
    I've been getting some quotes from both HVAC companies and fuel suppliers.

    Is one considered better than the other? I'm just trying to understand who the true experts are in the field.

    Fuel suppliers seem to be way lower priced for the same systems and work. But I'm ok paying more if they are more proficient and understand the install better. Surprised how much of a swing there is between the two.

    I'm a true believer in "pay for what you get" but I also don't want to get ripped off!
  • SuperTechSuperTech Member Posts: 546
    Since you are going with LP if I had my choice I would installed an Energy Kinetics Accel CS condensing boiler. The ones I've seen were easy to work on and seemed to be built to a high quality standard that seems lacking in other mod cons.

    Out of the two you mentioned I would get the Lochinvar, I never liked Weil McLain.

    I would probably recommend a nice cast iron boiler or steel EK-1 frontier or Resolute with a conversion burner over any mod con. AFUE isn't the best way to judge energy efficiency. And I'd rather my customers have a reliable system that doesn't require model specific parts. That way I can be confident that I can get the heat fixed at 1 a.m with what I stock on my truck. But I have honestly only had one emergency call on an EK conversion burner. And it was a quick fix, they are a very stout boiler. I think in terms of real world fuel usage the difference between these boilers and a mod con is minimal. And you will have a boiler that is more reliable and definitely longer lasting.
    No I don't work for Energy Kinetics. I'm just a service technician that has become a fan of their equipment over the years.
    If you decide you must have a mod con give the Accel CS some thought. I'd stay away from mod cons with the Giannoni heat exchanger and I stay away from Weil McLain NTI Trinity. Too many issues...
  • flat_twinflat_twin Member Posts: 178
    We did an oil to natural gas conversion in 2016. We're very happy with the Weil Mclain Eco 110. It's a simple fire tube boiler, not a coiled water tube like the WM Ultra.
    This is in a 170 year old house with 10 cast iron radiators, 2.5 inch main pipes on a single zone. The one zone system makes it easier to keep the boiler running continuously at low fire.
    If you do the numbers (heat loss and emitter survey) and find your radiators are capable of making far more heat than you need, a mod con is a good match for your home.
    Comparing two mild winters back to back and adjusting for a small difference in heating degree days, we saved 45% in heating costs with the modcon over the fuel oil boiler.
  • SteamheadSteamhead Member Posts: 12,536
    flat_twin said:

    Comparing two mild winters back to back and adjusting for a small difference in heating degree days, we saved 45% in heating costs with the modcon over the fuel oil boiler.

    Was the oil boiler suffering from lack of proper maintenance, with a lot of soot and sulphur accumulation inside?
    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.
  • flat_twinflat_twin Member Posts: 178
    The oil boiler was a 12 year old Tempstar rated at 110 btu. I don't know what size nozzle was used. It was cleaned and serviced annually by a heating contractor except for one year when I skipped the service call. The tech showed me how much accumulated in two years so I didn't do that again.
    While we had the fuel oil boiler we used a programmable thermostat. It was set at 65 while we were at work and at night, otherwise 69. With the modcon boiler we keep it at 72 and no setback.
    Winter of
    2015-16 Fuel oil $1760 @ $2.20- 2.40 gal. We considered this heating season a bargain compared to previous years when fuel oil was well over $3 per gallon and at times was pushing $4

    2016-17 NG $980 heating only. IWH installed late May '17
    NG $1.12 per CCF
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