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Oil to Gas Conversion-New Forced Hot Water Boiler + HW Recommendation??

wolfetone Member Posts: 8
Hi guys,

So I am located in MA, and I am converting from oil to gas for a 3200 sq foot home which currently has an oil boiler and HW from the boiler. Nothing wrong with the oil system, its been solid and in place since the 90s I would say, but we got gas and looking to free up space in the basement where the oil tank is and stop filling up with oil.

Any recommendations for a new Forced Hot Water Boiler?

I am big against Chinese or Asian manufactured parts and then assembling it in the USA and calling it American. I am not against European stuff of high quality either.

Budget is not an issue, just looking for an efficient and reliable well built system. We have hot water currently off the boiler, not against other options, im here to take everyones advice. We have a 45 Gallon Superstor, we have a 5 bedroom home, full house with kids. Superstor capacity has been an issue at times of high demand ie washer and dishwasher on and a shower at same time coincidence!
We have old school cast iron radiators.

I had read a lot in the past about Viessmann Vitodens but my plumber had a bad experience with a brand new one a customer got and was without heat and hot water in New England winter in January for 6 weeks! So he had a bad experience with them.

The gas is from the mains!


  • lchmb
    lchmb Member Posts: 2,997
    I've done many Viessmann and never had an issue where a client went more than a weekend waiting on a part. If it were down for more than a week in harsh climate I think I'd have pushed them to be on site and fix it or put in a new one. The superstor is a good brand. I run mine at 150 degrees and mix down. Have someone size it based on total load. Your install and start up are a huge part of any system you install. I've done IBC, System 2000 (which is US and I like) and many other's. If set up to spec and serviced properly you can get years of happy heating. If done wrong........ Ask for references, ask for pictures of install's they've done... do your homework now...
    HVACNUT Member Posts: 4,594
    Baseball, hotdogs, apple pie, and Energy Kinetics Accel CS.
  • newagedawn
    newagedawn Member Posts: 586
    get a buderus they are top of the line, and i have heard alot of bad things about viesman also, i personally dont like or use them, i converted a customer 4 yrs ago from oil to gas with a buderus and they rave on the efficiency and low bills, something to consider
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
  • flat_twin
    flat_twin Member Posts: 318
    We replaced our oil boiler with a natural gas modcon two years ago and later added an indirect water heater. Very pleased with the results. 45% less to heat in the winter and 30% less electricity with the indirect WH.
    We have cast iron radiators and large iron pipes that only require boiler water temps of 85 to 128 degrees so the boiler is condensing all the time and running very efficiently. If I could do it over I would have selected a 70k btu Weil McLain Eco boiler instead of the 110k Eco boiler the contractor insisted on. I figured our heat loss is about 60k with a Slant Fin heat loss app (after the boiler was installed, duh). The smaller boiler would have a lower minimum firing rate of 14k btu vs 20k btu and cycled a little less when temps are in the 40's and up. Still, it doesn't short cycle due the mass of the water and iron radiators all on one zone. The WM Eco is a very simple modcon with simple controls for one zone and domestic hot water. It's made in North Carolina. The stainless steel firetube heat exchanger is made in europe.
    You should calculate your home's heat loss. Also calculate the btu output potential of your cast iron radiators to determine what boiler water temperatures will be required. Also the minimum heat requirements of your smallest zone (if more than one). Be sure your water is within spec for the new boiler too.

    Our indirect water heater is 38 gallons set at 140 degrees and mixed down to 122 before it goes to the faucets. It's just two of us with one bathroom and we never run out of hot water.


    http://www.columbiaheatingsupply.com/page_images/Sizing Cast Iron Radiator Heating Capacity Guide.pdf
  • hot_rod
    hot_rod Member Posts: 16,315
    Have the contractor do a load calculation to size the boiler correctly. A mod con with outdoor reset would be a good choice.

    I would go with the installers brand recommendation as he will be the one to service and repair if ever needed. Generally that have taken factory training for the brands they install.

    I'd suggest all 70 or so brands of mod cons have good products out there. Stay with a brand that is popular in your area and has parts and support locally.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream