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Stick w/ Oil? Convert to Gas? If latter - convert or new boiler? Costs? Thanks for the help!

We have 10 year Weil Mclain. Would appreciate advice and costs on options.

We're in PA - about 25 miles North of Philly. We've got a 10 year old Weil Mclain boiler that is way oversized - 240K. The crooks who sold/installed it to the previous owner put in a full 2 gallon nozzle! It was there when we bought 4.5 years ago. We can finally get gas now and I've placed the order w/ PECO - finally we'll have a gas cooktop!

So ... we've got options! Let's say that I kept the boiler as is - and downsized the nozzle to put out say 100K btu (acceptable nozzles are listed on the side of the boiler and this falls into the range) - how much oil might I save if I did NOT mess with anything at all for the boiler?

I've done several detailed heat loss analysis workups and I get about 82000, while trying to be at least a bit conservative. The structure is 1875 - mostly brick, except for an addition put on the back about 40 years ago). The house is also a twin so one wall is shared with the house next door - except the addition off the back (open on 3 sides and it's 2 stories). 2950 total square feet, not counting full basement - most of which is completely underground. We did a lot of air sealing and insulating this past spring (we did a full energy audit w/ blower test). This past summer was much more comfortable than prior years.

Most of the house is 4 levels and 2 zones (zone 1 is front of house, zone 2 is middle of house. zone 3 is ONLY for the addition off the back - 2 stories over the basement. But zone 3 is currently drained out empty. A few years ago we installed a high end Fujitsu dual mini split heat pump and have been using that for heating/cooling for the rear addition, and it works pretty well.

I'm trying to get some quotes from local guys here and would appreciate some basic figures, parts and labor separately - if we go with the following:

- Carlin EZ conversion

- Outdoor reset

- (optional) indirect water heater, perhaps a 40 or 50 Amtrol? They seem to be less expensive and ppl say good things about them (current boiler doesn't seem to have integrated connections for this so if we do go w/ one vs. a standalone gas water heater we'd need a small separate circuit built for that). There is plenty of room next to the boiler.

What about sticking w/ oil heat, downgrading the nozzle to something sensible and installing an outdoor reset?

Also - does anyone have really good figures on recovery value for an indirect water heater vs a high recovery 50 gallon stand-alone gas water heater? We can get a Rheem 42vr50-40f for under $600 delivered. I kinda like the idea of a standalone gas water heater so that we have hot water regardless of what happens w/ the boiler.

That aside, if we did go with simply "a new gas boiler" that can be directly vented (to avoid lining chimney), any cost estimates? (there is an external wall in basement for direct venting). And that aside ... the high efficiency stuff is directly vented w/ pvc but they seem really expensive - it would take a LONG time to get payback on 90% vs 80% when one is already saving on gas.

Thanks very much in advance, for your assistance!



  • Zman
    Zman Member Posts: 6,539


    To compare the costs of various fuels I like this

    You just put in your local costs and boiler efficiency. The oversized boiler will reduce your present efficiency.

    I don't think you are a good candidate for a conversion burner. Your boiler is just too big.

    I am not much of a fan of the amtrol . They have small exchangers and often calcify on the domestic side

    The rheem water heater you are looking at is 62% efficient and will have a BTU output of 24,800.

    A good properly sized indirect tank will have the same efficiency and output as the boiler.

    My personal preference is the triangle tube prestige boiler with a heatflo indirect.

    The TT110 looks like a good fit.

    One of the rules on this site is "Don't discuss pricing..."

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • HomeOwner1
    HomeOwner1 Member Posts: 134
    We had an almost identical situation

    We chose to go with a Navien CH-240 combi boiler. Worked really well and was extremely reasonable on the budget. About the same cost for us as putting in a 82% boiler.

    We have a similar heat loss and 3 full baths with a bigger home then yours in New Jersey.
  • Zman
    Zman Member Posts: 6,539

    Whatever Navien is paying you, It is not enough!

    Keep up the good work.

    I am trying to sell some AC units to Eskimos. I could use your help.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • HomeOwner1
    HomeOwner1 Member Posts: 134

    For our boiler, PVC up the chimney and cold air supply vent out the side of the house.

    Don't go the exhaust out the side of the house method. Condensing boilers put out a cloud of moist smoke when running.
  • Zman
    Zman Member Posts: 6,539


    Do you work for Navien?

    This question has been asked before with no response.

    It sure seems like you are more than a compulsive homeowner and you are essentially posting advertisements for Navien (rule 3).

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • HomeOwner1
    HomeOwner1 Member Posts: 134

    What's your beef against combi systems?

    We got tired and very frustrated with most of the installers we had out for quotes telling us that our installation was not ever possible, with any of the combi brands. Most didn't even bother to even investigate any combi units and dismissed them immediately.

    Almost all of them attempted to steer us into the cast iron 82% efficiency direction with a natural gas switch and 75 gallon hot water heater with Chimney liner.

    Others tried to explain to us that our only option to have a high efficiency system involved a condensing boiler with an indirect costing us at least four times the amount we actually wound up paying.

    For a similar effort and price as the cast iron, hot water heater and liner installation, we have a high efficiency unit. Granted, for a couple grand more it could be a more recognized brand name, but still even then, half the amount to what most installers were telling us was our only high efficiency option workable.

    We have no problem running the Kia of the boiler world and not the Rolls Royce.
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