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Need to make quick decision on replacing oil burner with gas

jhalljhall Posts: 3Member
Been putting off replacing a very old oil burner for too long, now its late November, and my oil burner is on its last legs, and need to make a quick decision before it gets any colder. Am pretty sure we want to switch to gas, as its already in the house (currently using for stove and water heater), and that part seems like a no-brainer

Have talked to one plumber I have used before, as well as rep from a supply company, and have one more heating guy coming out tomorrow. But just some quick specs, and a few questions to the board, so I know what questions to ask

Specs. House is 1928 era, about 2200 square feet, and mostly old hot water radiators on a single zone. There is a second zone with some baseboards in a new addition.

We love the heat from the old radiators, and want to make sure the new system runs them as effectively as our 35+ year old Weil-McLain old burner, even if not the absolutely most effecient setup

So some questions:

1) People I've talked to so far all suggest that we should avoid very high-efficiency gas, as they are known to be problematic. Also, where the current furnace is located is adjacent to chimney, but not on an outside wall, so may be problematic for direct vent. Do people concur?

2) Is there any reason a gas furnace would be less reliable in heating a system with old hot water radiators than our current oil system?

3) First plumber mentioned brands Burnham and Buderus. Both seem to not have the greatest of reviews online. What is the view of those brands?

4) Chimney has an old clay liner that we have been told should be replaced, but we have been holding off because we weren't sure whether we would be going oil or gas. What type of liner do I need for a gas furnace.

5) Both people who have been out have measured the radiators, but didn't do a heat/loss assessment. How necessary is this. We don't have the best of insulation.

Any other specific questions I should be asking before making a decision?

Comments

  • Jamie HallJamie Hall Posts: 10,182Member
    In no particular order. Heat loss is the first item on the agenda. Only that way can you come even close to the correct boiler.

    Both Burnham and Buderus have proven to be good reliable units. I wouldn't trust most online consumer reviews... far more important that the exact brand is the skill and competence of the people who install it and will then stand behind it and maintain it.

    You will need a chimney liner.

    A gas boiier will be just as reliable as the oil boiler.

    However, I would ask if you have enough gas. You do have gas, true -- but you may not have enough capacity. This must be checked.

    As regards high efficiency (that is, mod/con) boilers vs. some of the older style units -- you do gain some in running cost, particularly in the shoulder seasons, if you have enough radiation in the building to be able to run low enough temperatures (see the heat loss -- compare each room to the installed radiation). However, you also have higher maintenance costs. The jury is still out -- so far as I am concerned -- on relative longevity, which also plays into the cost equation.

    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
  • jhalljhall Posts: 3Member
    Thanks Jamie. First plumber said yes there should be plenty of capacity on the gas line/meter. Will confirm with second. Also will ask for them to do heat loss assessment.
  • HVACNUTHVACNUT Posts: 1,974Member
    You can do the heat loss calc yourself so you know what you need. Download the Slant/Fin heat loss app. Simple and free.
    If you go with a gas mod con with outdoor reset and large rads, it might take a few return trips from the installer to correctly dial in the parameters for the shoulder months. Especially if its a boiler with a 10:1 turn down ratio. Or learn to do it yourself. Make sure they leave ALL the manuals.
    Gas is cheaper now, but #2 fuel smells like.. Victory!
    Sorry, I'm an oil guy at heart.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,514Member
    @jhall , good luck with the heat loss request. I'll bet you a coffee they will tell you you don't need one. You can download the Slant Fin app and do it yourself at least as a check against your quotes.

    Other than that @Jamie Hall is spot on with his advise. Two most important things are a heat loss and a qualified contractor.

    Depending on your location you may find someone under 'find a contractor" on this site
  • captaincocaptainco Posts: 424Member
    When replacing just the burner the burner is sized for the boiler not the house. Can't put a 2-cylinder engine in a truck because you are going to drive slow and not carry anything. The boiler has a mass that must be heated. Boiler reset controls take care of the heating load.

    Mod-Cons are the best boiler replacement but not sure if they are that effective on cast iron radiators.
  • newagedawnnewagedawn Posts: 549Member
    natural gas is the way to go, the bills are so much cheaper,
    as far as boilers go buderus is top of the line, but mod cons are great for large water content systems, there excellent on cast iron radiator systems and definitely line the chimney with the same size as the flue from your pick, except you dont need a liner with a mod con boiler, something to consider, spend the extra money on a good model mod con you wont regret it
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
  • John Mills_5John Mills_5 Posts: 889Member
    Aren't mod-cons good for cast iron radiation since they tend to run cooler than copper fin tube?
  • jhalljhall Posts: 3Member
    edited November 2017
    Yeah none of the plumbers wanted to do the heat loss. Answer from the one I like best is "Heat losses are done on new construction or remodels. By measuring all your baseboard and radiators that was your heat loss there....because it’s from the original house. And it came out exactly what I thought between a four and five section and we bumped it up to a 5 section more than enough." Both of the other guys just measured the radiators too.

    Both guys also recommended 5 section boilers: One is recommending Buderus, the other Weil McLain. Both traditional gas boilers. No one seems to be recommending we do high-efficiency with our radiator setup.

    Other variable that concerns me, is one guy says we don't need a chimney liner. The other says we absolutely do, and it would be unsafe to install without. Our chimney is pretty old and we had been told previously by a chimney company that we need a new liner. Just had been putting it off till we decided whether we were definitely switching to gas, cause it would be a different liner than if we stuck with oil.

    So at this point I'm leaning toward the Buderus-liner guy vs the McLain-no Liner guy even though he's pricier.

    One other variable on water heating: 40 gal SSU Super-Stor Tank vs. 52 gal SS Laars indirect fired HW heater.

    Thoughts?
  • gschallertgschallert Posts: 170Member
    jhall said:

    No one seems to be recommending we do high-efficiency with our radiator setup.

    That tells me no one you're dealing with understands high efficiency modcons. Your high mass hot water radiators are absolutely perfect emitters for a high efficiency modcon.
    jhall said:

    1) People I've talked to so far all suggest that we should avoid very high-efficiency gas, as they are known to be problematic. Also, where the current furnace is located is adjacent to chimney, but not on an outside wall, so may be problematic for direct vent. Do people concur?

    LOL, high efficiency boilers are only "problematic" for clueless installers. The existing chimney may be able to be used as a chase (providing you don't have any other appliances venting from the same flue) if you don't want to line it. If not modern direct vent appliances tend to have plenty of flexibility to route to an outside wall if necessary.
    jhall said:

    5) Both people who have been out have measured the radiators, but didn't do a heat/loss assessment. How necessary is this. We don't have the best of insulation.

    Give both a pass and find a more qualified installer, emitter capacity is only part of the information needed to properly size a boiler. Have you checked this site's find a contractor?
    https://heatinghelp.com/find-a-contractor/
  • Jamie HallJamie Hall Posts: 10,182Member
    As @gschallert suggested none too strongly... a heat loss on the building is almost essential to properly size the boiler for a hot water heating system. In fact, I don't see how you could do it without one.

    Find someone who knows what they are doing.
    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
  • BrewbeerBrewbeer Posts: 571Member
    @jhall if you can use a tape measure, you can do the heat loss yourself with one of the free online calculators. It will take a few hours to do correctly. If a heat g pro does it, expect to pay them for the time it takes to do it.
    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: http://forum.heatinghelp.com/discussion/154385
    System Photo: https://us.v-cdn.net/5021738/uploads/FileUpload/79/451e1f19a1e5b345e0951fbe1ff6ca.jpg
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