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Propane Boiler

ScottMcNab
ScottMcNab Member Posts: 50
Thanks in advance for any help. I recently had a propane boiler installed. Just trying to figure everything out and get the right settings. A little background. The circulation pump is controlled by the house thermostat and the boiler is controlled by a low limit aquastat. What temperature should I set the low limit and the differential (5 degrees to 30 degrees). Seems like a waste of propane this time of year keeping the water hot when the home doesn't call for heat that often. Daytime highs are around 7 degrees. Would an outdoor reset control be worth the money? The boiler is only used for home heating as I have a separate electric water heater. Just seems like it runs quite a bit. I'm used to an oil Boiler so maybe I'm overthinking things.

Comments

  • Zman
    Zman Member Posts: 7,561
    What model boiler?
    What type of radiators?
    How do you heat domestic water?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • ScottMcNab
    ScottMcNab Member Posts: 50
    Biasi B-4 propane boiler. Slant fin baseboard rads. Separate electric hot water heater. Boiler is only for home heat
  • DZoro
    DZoro Member Posts: 1,048
    The larger temp difference will help stop short cycling of the burner. I'm not sure why you would be set up as a hot boiler. That will waste gas. I would have the thermostat go to TT on the boiler, which then will control pump and the boiler. Yes get the ODR control hooked up.
  • ScottMcNab
    ScottMcNab Member Posts: 50
    Heating guy said it's to prevent the boiler from getting cold and causing stress with temperature fluctuations. Condensate might be the other issue
  • HVACNUT
    HVACNUT Member Posts: 5,804
    True, you dont want the flue gasses to condense with a cast iron boiler, but that shouldn't really be a problem unless there's a large water content. With normal heat cycles, the water temp should stay above 135.

    What type of aquastat is on the boiler?
    Which burner?
    Was a chimney liner installed?
    Did they do a combustion test?
  • ScottMcNab
    ScottMcNab Member Posts: 50
    This time of year the water would go to zero if no call for heat correct?
    Honeywell L4006A
    Riello 40
    Aluminum chimney liner installed
    Not sure on the combustion test
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506

    Heating guy said it's to prevent the boiler from getting cold and causing stress with temperature fluctuations. Condensate might be the other issue

    If piped for boiler protection, and circ hold off provided by aquastat, it won't be a problem. With the low water content it will get above 140° pretty quickly.

    Plus, on your next cleaning, you would see signs of condensation in the heat exchanger/chamber.

    This time of year the water would go to zero if no call for heat correct?

    Honeywell L4006A

    Riello 40

    Aluminum chimney liner installed

    Not sure on the combustion test

    Room temp at best...not 0. Pressure may drop.

    Do you only have a high limit aquastat on the boiler? You should have another control (unless thats your low limit attached to the circulator).
    Picture time :)

    steve
  • ScottMcNab
    ScottMcNab Member Posts: 50
    It's wired up as a low limit aquastat. Let's say I set the aquastat to 135 degrees Fahrenheit and differential of 30 degrees. The boiler fires at 135 and shuts off at 165. Circulator pump has its own relay that is controlled by the house thermostat. When the call for heat is needed then the circ pump kicks on.
  • DZoro
    DZoro Member Posts: 1,048
    So why on a beautiful sunny day is your boiler maintaining 135 - 165* of hot water. Which is probably migrating up into your home, which is already warm, and the windows are probably open. Well at least the pump isn't running....
    Makes no sense, leave the boiler off until you need heat. When the stat calls for heat it starts the boiler, water warms up, pump comes on at 140* and gives you heat when you actually need heat in the home.
  • HVACNUT
    HVACNUT Member Posts: 5,804
    The L4006A is a HIGH limit, open on temp rise aquastat.
    If you set it to 170 and 30 on the white wheel differential, the temp will drop to 140, then go back up to 170.

    So what you've got is ok for condensate protection, but not great for saving $$.

    I'm not positive but I thought the Biasi B boilers came with a Hydrostat 3250 Plus or the Beckett Aquasmart.
    Both are standard with Boiler Reset that will regulate water temperature using thermal targeting.
    Also, both offer an Outdoor Reset option. The Beckett OD sensor is wireless.

    In NY its code to have either ODR or boiler reset when the boiler does not have a tankless coil, which yours does not.
  • ScottMcNab
    ScottMcNab Member Posts: 50
    The way it's wired though is you set the aquastat at 140 and 30 on the white wheel. So when water temperature drops to 140 burner comes on and goes to 170 and shuts off. With what I have currently, would I be able to have the burner controlled by the home thermostat to come on when a call for heat and the circ pump controlled by the aquastat to come on no earlier than 140 water temperature?
  • HVACNUT
    HVACNUT Member Posts: 5,804
    Yes, by installing a Hydrostat or Aquasmart.
    With either of those, the thermostat controls the burner and circulator.

    You're confusing yourself though. The L4006A is, and only is a high limit no matter how its wired.
  • ScottMcNab
    ScottMcNab Member Posts: 50
    Oh I see. So the 5-30 degrees above the set temperature of say 140 would be the high limit? Is it an expensive job to switch to what we're talking about?
  • ScottMcNab
    ScottMcNab Member Posts: 50
    Let's say I leave the boiler how it is for now. What is the best and most efficient water temperature to set and differential? Considering daytime highs outside are 7 degrees Celsius and nighttime lows about 0 degrees Celsius. The circ pump rarely if ever runs as the boiler hot water makes its way back up the pipes to the rads without pumping. Save on hydro I guess.
  • pecmsg
    pecmsg Member Posts: 4,776

    Let's say I leave the boiler how it is for now. What is the best and most efficient water temperature to set and differential? Considering daytime highs outside are 7 degrees Celsius and nighttime lows about 0 degrees Celsius. The circ pump rarely if ever runs as the boiler hot water makes its way back up the pipes to the rads without pumping. Save on hydro I guess.

    So on warm days that's also happening?

    Get it installed and set up properly!
  • ScottMcNab
    ScottMcNab Member Posts: 50
    Yes. Everyday
  • HVACNUT
    HVACNUT Member Posts: 5,804
    edited October 2018
    Let's use 170° limit with a 30° differential.
    The burner will start, bring the temp to 170° (high limit).
    Boiler temp drops to 140° and the cycle starts again.
    The circulator only runs on a space heat demand and will run as long as theres a call for heat, regardless of boiler temperature.
    During the heat call from the thermostat, the boiler temperature will drop, and once it hits 140° (30° differential), the burner will come back on to raise boiler temp to 170°.

    There will be condensate protection because boiler temp stays above 135°, the approximate dew point of the flue gasses.

    There will also be a poor mans freeze protection of the heat pipes by the circulator running even if the burner fails to fire.

    I think you should start with 170° limit and a 30° differential.

    On real cold days, if the house wont reach the desired temperature, you can raise the limit by 10° increments. But do not go over 200°.

    If the baseboards are getting warm without the circulator running, then the installer did not provide a flow check valve and you'll need to call him back to correct it.
  • ScottMcNab
    ScottMcNab Member Posts: 50
    Sounds good to me. Thanks HVACNUT for all your expertise and walk through. The way it's set up will help with certain things and dead of winter will need to be that hot so no real waste of propane anyways. I'll change those settings when I get home. Do you suggest piping insulation in an unfinished basement or let the heat from the pipes radiate in the basement? Thanks again
  • ScottMcNab
    ScottMcNab Member Posts: 50
    How much propane will the Riello40 burn? I was used to oil so Gph. I'm sure the propane burner isn't using as much as I'm thinking since it should be more efficient.
  • HVACNUT
    HVACNUT Member Posts: 5,804
    The insulation question is up for debate, but if it was me, I'd insulate.
    Nobody except Mother Nature knows how much propane you'll use, but where I'm from, Long Island New York, BTU to BTU, fuel oil is way cheaper, even against a 90+% efficiency boiler.
    You mentioned celcius so I assume your in Canada and cant even guess.
    Habs?
    Leafs?
    Jets?
    Canucks?
    Oilers?
    Flames?
    Nordiques?
    Maroons?
    Oh wait, never mind.
  • ScottMcNab
    ScottMcNab Member Posts: 50
    I was just curious how much that burner would go through say in an hour. I'm hoping in the end that making the switch is worth it. I'm definitely a leafs fan! And yes from Southern Ontario
  • ScottMcNab
    ScottMcNab Member Posts: 50
    See how this winter goes and might have to look into having the boiler set up different for next heating season if I go through crazy amounts of propane. Last winter cost me about $2500 in furnace oil.
  • ScottMcNab
    ScottMcNab Member Posts: 50
    What's the harm without a flow check valve and the water backing up to heat the rads without the circ pump? It's heating the house decent and using no hydro for the pump.