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Coal boiler installation questions

Linkman24Linkman24 Member Posts: 10
Hi,
I just moved my coal boiler out of my basement into a room off a newly built attached garage and I have some questions on what I need to change to hook it back up into the system since it is now 80 ft from the main heating loop. I originally have 1 inch pex connecting this boiler to the system but think I may need to go to a larger size pipe. Also, I have questions as to whether I can use the current pump, which is a Bell and Gossett NRF-22. The coal boiler is rated for 144K BTU and the house is a well insulated 2700 sq ft. Let me know if you need any other information.
Thanks.

Comments

  • hot_rodhot_rod Member Posts: 11,889
    If in fact it is a 144K output, you want to move around 14 gpm.

    Do you need that much heat energy? A load calc would be the only way to know for sure.
    A WAG would be 25 btu/ sq. ft X 2700 sq. ft = 67.5K.
    Boiler may be twice the size you actually need?

    Some times a buffer tank is needed to simmer them down or the idle cycle can be creosote forming monsters. You may have the burn procedure down, fire it to the load if possible.

    Manufacturers have capacity charts for pex on their websites. If you only need 67K or less the 1" pex would move that load.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Linkman24Linkman24 Member Posts: 10
    A heat calc was done on the house a few years ago and I was told I could get away with a boiler that had the equivalent of 125K output. I was in the market to replace my old Weil Mclain, which was my back up boiler as it would not keep up with demand once I put an addition on my house to make it 2700 sq ft. I live in the finger lakes region and it gets cold here. The coal boiler is much bigger than needed to heat the house and worked just fine with 1 inch pex when it was in the basement 10 ft from the main loop. I don't think that is going to cut it being 80 ft from the main loop now.
  • GroundUpGroundUp Member Posts: 639
    Is the house missing a wall? Odds are VERY slim the heat load is anywhere near 46 BTU/sq ft. How big was the WM that couldn't keep up? With any sort of envelope, the 7-8 GPM you can squeeze out of 160ft of 1" pex should be great plenty to heat the place- but the NRF-22 will not get you that with 1". No harm in upsizing the piping, this is one of the instances where more can be better
  • Solid_Fuel_ManSolid_Fuel_Man Member Posts: 1,715
    Consider that I heat 3200 square feet with 47,000 btu/hr when its -20F here.

    Even if you double that to 100,000 btu/hr.

    I'd reconsider your heat loss. How much fuel do you burn per winter?
    Serving Northern Maine HVAC, and Controls
  • Linkman24Linkman24 Member Posts: 10
    Thanks for the responses. I burn around 5 1/2 tons of rice in a season keeping the house at 70 degrees. The old boiler is a Weil Mclain GV-4, rated for around 90000 btu/hr output. I am going to revisit the heat loss calculation. If I upsized the piping to 1 1/4, could I use the NRF-22?
  • HVACNUTHVACNUT Member Posts: 2,569
    How does rice coal compare to carbon fossil coal emissions wise? Just curious. I didn't know rice coal was a thing. And I love my Uncle Ben's. Is the WM operating? Do you still plan on replacing it with a new backup?
    What about a dual fuel?
  • hot_rodhot_rod Member Posts: 11,889
    You really need to determine how much heat you actually need to move. If the old 90K boiler heated the home, then 9 gpm from the coal boiler should also do the job.

    If you want or need to move the full output 0r 144K, probably need larger tube.

    Here is an example of then pressure drop charts for 1 & 1-1/4"
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Linkman24Linkman24 Member Posts: 10
    HVACNUT-The rice coal is actually small sized Anthracite coal. I am keeping the coal boiler but going to replace the back up propane boiler since it is not big enough to keep up with the heat demands of my house after I put on a 1000 sq ft addition that increased the size of the house to 2700 sq ft.
  • Linkman24Linkman24 Member Posts: 10
    Thanks hot rod. The old boiler is going to be replaced next year because it cannot keep up heating my house after I put a 1000 sq ft addition on to bring up the sq ft to 2700. I am going to take a crack at heat loss calc. Do you know a good web site to go to for the calculation worksheet. Another question, go with Pex or copper?
  • DZoroDZoro Member Posts: 903
    How many btu's of radiator capacity do you have?
    D
  • pecmsgpecmsg Member Posts: 909
    Linkman24 said:

    HVACNUT-The rice coal is actually small sized Anthracite coal. I am keeping the coal boiler but going to replace the back up propane boiler since it is not big enough to keep up with the heat demands of my house after I put on a 1000 sq ft addition that increased the size of the house to 2700 sq ft.

    Somethings wrong with the equipment or setup!
  • pecmsgpecmsg Member Posts: 909
    Got pictures of the piping on the LP boiler?
  • Solid_Fuel_ManSolid_Fuel_Man Member Posts: 1,715
    To be completly honest, the only downside to larger 1-1/4 PEX is the initial cost. The lower flow restriction will pay for itself with the use of a smaller circulator.

    PEX is also more restrictive than copper for the same nominal size. I'd go with the larger regardless of the heat load and use an ECM circulator for the greatest savings over the long term.

    Also, at the very least measure your radiation, if baseboard, total length and model. I'll bet there is less than 100,000 btu/hr total capacity anyway. Most houses have far less radiation capacity than boiler.

    The more information (and pictures!) the better we can help with sizing etc. It pays big dividends in the end, a few hundred dollars now saves thousands over the life of the equipment.
    Serving Northern Maine HVAC, and Controls
  • Linkman24Linkman24 Member Posts: 10
    Sorry for the length of time to reply but I have been busy all weekend insulating my garage to get it to the point so I can install the coal boiler to heat the house before it gets real cold. In reply to the question of how many feet of heating fins for the house, I have 96 ft of baseboard in the original house and 1500 ft of pex with heat shields in the radiant floor heating in the 1000 sq ft addition. I have also attached some pics of the original coal boiler set up before I moved it and of the current set up for the propane boiler. Let me know if you have any questions.
  • Linkman24Linkman24 Member Posts: 10
    Forgot the pic of the coal boiler. Here you go:
  • Linkman24Linkman24 Member Posts: 10
    A couple other things that I was told by a local guy that uses this website and suggested I reach out. He told me that since I was moving the coal boiler, he would replace all the copper from the boiler to the main feed and return lines with black iron. He also said to get replace the air scoop with a spirol vent and upgrade the expansion tank from 30 lbs to 60 lbs. The reasoning for this was the distance the water was moving to help get the air out.
  • Jamie HallJamie Hall Member Posts: 11,227
    On heat loss -- the above is correct on measuring the radiation to figure out just how much heat you can dump into the house. The radiant floor is a bit more problematic -- but anything over 25 to 30 BTUh per square foot is kind of optimistic.

    And for calculation, there are a number of easy to use heat loss calculators out there on the wed. I happen to prefer the Slant/Fin one, but it's not the only one out there.

    And one last thought -- the larger expansion tank is a good idea. Not to get the air out -- the expansion tank size has nothing to do with getting air out -- but because you will now have a greater volume of water heating and cooling, and that is what matters with expansion tanks.
    Jamie

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • DZoroDZoro Member Posts: 903
    That GV is known for clogging pumps and H/E water flow especially in the pipe configuration that you have. Age is hurting your btu output. The rated capacity is just fine. Boiler flushing and chemical cleaning of the H/E should be done. At the same time that is a pretty old GV.
    I'd stick with copper piping, but that's just my opinion, agree with the other ideas spirovent will do a good job of air removal.
    D
  • mikeg2015mikeg2015 Member Posts: 990
    On a hot water system, a boiler is only too small of the flow rate is too low or it fails to reach setpoint. Other wise a larger boiler just costs more and waste fuel short cycling.


    Was in a house last week. A triangle tube 110k boiler. Only 40’ of baseboard. I estimated 30k at Even 190f water. Over pumped to squeeze what we could out if it Delta T was 8f. House needs about 40k on the oldest days.
  • Linkman24Linkman24 Member Posts: 10
    HI guys, I am back. I have the drywall up in the garage and want to finalize what is needed to hook up this boiler. A few things I found out along the way. The boiler has a net btu output of 122K btu. The heat loss calc according to the slant fin app was 65981. I calculated total available heat load at 86560 (96 ft of baseboard and 1120 ft of radiant floor heating). I came up with a flow rate GPM of 8.656 and a longest run in supply loop of 105' calculating a pump head of 6.3. Judging by these numbers, I think I need the 1 1 /4" pex for the supply line or 1" copper. Any idea of pump size and brand? Do I double the pump head # since the loop for the supply is 208'. I want to get this right so your help is much appreciated!!
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