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Converting to nat gas-a case study

Hello all,

New home owner here and new to heating systems, let alone steam systems - other than blindly using them.  My current system is heating oil, steam one pipe with an external above ground tank.  210 btu (corrected) McWeil Lain.  house ~ 2600 sq ft.  Photos of radiators and boiler, pipes attached.

I solicited estimates from various people to convert and was bothered that none of them seem to do any calculations after having a look at my radiators, if they looked at all, and all of them came up with the requirement of a unit about the same btu as I currently have. 

I had a terrific home inspector (Kyle Kubs-Benchmark Home Inspection here in NJ) and he recommended the "We Got Steam Heat!" book to me, so I knew a little about what to look for after reading it in its entirety.  I found another company (Joe at Ecuacool in NJ) via the heating help website here, and he came out and was diligent about doing the computations.

The system I am scheduled to move to is a 120k btu with this boiler and this gas burner - links pasted below.   The idea is to ultimately achieve 87% efficiency.

I have some trepidation about the ability to go down to 120k btu and heat the house with efficiency (though know that this is all new to me), and Joe has agreed to let me post my situation here and that he would walk through it with me on this board so we could see how this transition could be accomplished.  The benefit to me is that others who frequent these boards and seemingly are passionate and wise about such systems will see it and perhaps chime in with their thoughts and the proposed solution.

This is new to me and I'm sure I've left out some important information that is required.  I believe Joe will chime in with my radiator sizing since he has the measurements.  My hope is to learn how this transition can be accomplished and whether or not I should be worried about it, and hopefully this thread will be of use to others also.

Proposed new equipment:

<a href="http://www.smithboiler.com/html/series8.asp">http://www.smithboiler.com/html/series8.asp</a>

<a href="http://www.carlincombustion.com/gas-oil-burner-products/burners/residential-burners-gas-fired/ez-gas-burner/">http://www.carlincombustion.com/gas-oil-burner-products/burners/residential-burners-gas-fired/ez-gas-burner/</a>

thanks so much for any input.  (the stick in the photos is 13"-14" long)



  • Steamhead
    Steamhead Member Posts: 16,736
    The Smith 8/Carlin EZ-Gas combination

    is a very good choice. And I think Joe will install it properly. So it should work well for you.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • BobC
    BobC Member Posts: 5,473
    Good combination

    I just had a Burnham v75 steam boiler replaced with a Smith G-8-3 with the EZgas burner in October. I've only used it for a few weeks but everything looks good. That Burnham v75 was much to large for my system, the new setup is still a little big but a lot better matched than the old setup was. The gas gun works well and is a little louder than my oil burner was but not by any appreciable amount.

    You have a bigger house than mine but as long as the installer knows what EDR (sq ft of radiator surface area) he is feeding you should be fine. just make sure the installer follows the Smith Piping instructions as a minimum, anything he does above and beyond will only make things better.

    There are a lot of folks who have installed this specific combination on this forum. If you have any concerns you can get answers here.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Bio
    Bio Member Posts: 278

    You are in good hands, not to many contractors in NJ know how to do a conversion using a power gas burner and with the smith boiler you are getting top quality boiler, the man knows his stuff, he recently installed a new boiler for me and I'm happy with the results
  • TRob
    TRob Member Posts: 20
    EDR worked for me

    Four years ago we had a new gas steam boiler installed. I read the 'books' and calculated the closest boiler match.  My installer agreed to follow my specs even though the selected boiler was just a bit smaller than the calculated total EDR.  The system has worked just fine and we never regretted going "one step smaller".
  • JStar
    JStar Member Posts: 2,752

    We came up with about 363 square feet of radiator load. The mains are mostly insulated, so I added 15% pickup, plus 15% for efficiency loss, and came up with a boiler input right near 120K. I believe the old 568 boiler is actually rated up to 210,000 BTUH. We see a lot of shocked faces when we go into a house, offering to install a boiler that is half the size of the old one. I mean, the old one worked, right? Yeah, and it could have also heated your neighbor's house. If I were in the business of selling fuel, I'd oversize my boilers, too. And then we talk about high 85-87% efficiency, and people don't believe it. Old habits die hard. Old steam habits die hard, come back, and haunt us for decades.

    The installation will include the boiler, oversized drop header, Vaporstat, maxxed out main venting, and a whole house radiator vent upgrade. I can't wait to compare the annual fuel savings.
  • ST2012
    ST2012 Member Posts: 4

    Thanks for all the comments, and thanks Joe.

    So 210k to 120k, so intuitively shouldn't the old boiler be running about half as much as the new one? is that inefficient due to starting/stopping?  Aside from the savings in gas vs. oil, I'm trying to understand where the savings comes from in terms of other efficiencies.

    1)  is the short cycling the big problem with having an over sized boiler, and is that what burns excess fuel with no benefit?

    2)  would you expect the house to warm up quicker with an oversized boiler?  it doesn't seem to warm up all that quickly as it stands
  • BobC
    BobC Member Posts: 5,473
    Slow venting

    My oversized boiler did build steam faster because it was almost 3X to big, but it would short cycle badly because it built pressure so quickly. that short cycling wastes fuel. The old boiler came up to steam in 8 minutes, the new one takes 10 and both take about 6 more minutes for the radiators to start getting hot. My venting back pressure is about 1.6 OZ while the main is venting.

    If the present boiler is not heating quickly enough it's probably because of inadequate venting.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Bio
    Bio Member Posts: 278
    Mtching EDR

    At 210k you will be firing at a higher btu (burn more fuel) filling all the Radiators unnecessarily fully hot and quick with many cycles and if you add a vaporstat will cycle even more, the rooms will get uncomfortable hot compared with a Boiler matching the houses edr you will burn less fuel, running at ounces of pressure, radiators no completely full but satisfying thermostat (most radiators are oversize for their room they're in why, waste fuel fill them complete)

    My system this morning ran with no cyles, at 1oz of pressure I have all Homnn40 and dont make any sound, it stays quite and all heat up evenly and 3/4 of the radiators got hot before themostat shut it off and never shut off on pressure
  • ST2012
    ST2012 Member Posts: 4
    Mtching EDR

    Thanks very much.  I've only about 4 weeks of experience with this system but I've noticed that most radiators don't fill up very much - maybe 1/4 to 1/2 depending on how cold, and then the unit cycles off when the appropriate temp is reached.  The main floor is a little cooler than we'd like it -small radiator in that area, and likely we have issues with our radiator vents which Joe is going to deal with also, particularly in one room where it doesn't even really come on, and turns out is the most critical room for us to heat.

    Thanks again.
  • Bio
    Bio Member Posts: 278
    Balancing the System

    So "Balancing the System" is also needed and Joe mentioned it on is post, you in the right track" remember "Vent Main Fast and vent radiators slow but complete" this make even, efficiency and comfortable heating
This discussion has been closed.