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Condensing Ol Boilers

Wayco Wayne_2
Wayco Wayne_2 Member Posts: 2,479
on Oil fired condenser boilers? I had a customer ask me about them the other day and I had to plead ignorance. The last I heard they had issues with corrosive wastes and byproducts. Are there any updates or experiences out there on The Wall?? WW

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  • Constantin
    Constantin Member Posts: 3,796
    I asked the same question a while back

    ...both here and over at OilTechTalk. Currently, the only company I know of to offer condensing oil boilers in the US is Monitor, with their FCX line. Other manufacturers that have condensing oil systems like Viessmann (VitolaPlus) are keeping them out of the US market.

    The consensus seems to be that the US fuel oil is still too contaminated to deal with the marginal benefit of a condensing design. That is, the sulfur will eat the secondary HX for breakfast, no matter what you make it of. Perhaps if the EPA has its way and lowers the allowable sulfur contamination in fuel to EU levels will we see more condensing boilers over here.

    I considered the FCX for a long while, as two units would give me ample heating capacity both for the house and the IDWH. Plus, besides their own modulation via the heatwise burner, the two-boiler setup would allow further "modulation". Alas, at $5,000 a pop, I'd have to boil a lot of water before the incremental efficiency improvement over a Opus O2 would make itself felt. Pity.
  • Robert O'Connor_6
    Robert O'Connor_6 Member Posts: 299

    What did you settle on?
  • Constantin
    Constantin Member Posts: 3,796
    No decision yet...

    ... I have a very open mind when it comes to equipment. As some folks at OilTechTalk pointed out, it pays to buy something the local maintenance techs are familiar with...

    I have further refined the HVAC-Calc numbers which the calc'ed heat loss to 107kBTU on the design day. Assuming that hydronics allow a 10% reduction in losses over what HVAC-Calc calcs for air-based systems, that brings us down to a DOE output rating of 97kBTU for the boiler. That opens a wide field.

    Hence, I am considering the following (in no particular order):
    • QHT Biasi SG3
    • Buderus G115-34
    • Burnham Opus O1-90 or V84
    • Viessmann Vitola VB2-33
    • Dunkirk DPFO-4
    All of these units can reach 86%+ efficiency while not condensing. Our installer will have to get back to me soon with some numbers regarding his heat loss calcs, equipment recommendations, and suggested cost...Then we'll make a decision.

    However, considering a 50' chimney, a interior liner of choice, radiant heat throughout, etc. is there a particular reason to chose one unit over the other?
  • Robert O'Connor_6
    Robert O'Connor_6 Member Posts: 299
    If it

    were my house it would be The Buderus with control and Carlin Oil Burner. Oil service is my business.

    I think Buderus has substantial equipment and has made a real investment in the US. I have installed quite a few.

    I can't comment on the Viessman my market doesn't support their sales.

    Burnham V_8 is a great boiler . I just wouldn't want to see any pin style in a cold start application.

    Biasi almost same AFUE as the Buderus but less cast iron. So probably thinner walls etc. Biasi has made no capital investment here and you are dependent on the importer. They are inexpensive and in my neighborhood guys love em.

    Opus i only know what i read . Good efficiency. Burnham and New Yorker have always made a good quality steel boiler.
    Interesting control strategy. Delivery and removal will present challenges.

    I would talk to the manufacturers about that chimney height. I have sen a couple that want no more than 45 ft. . I can't imagine the Buderus and Biasi not condensing at that height. Condensation will lead to rotten liners. Maybe one of those insulated liners is the answer. Or that may be a point for the Burnham V-8 with a warm start approach (It will have a slightly higher stack temp).



  • Wayco Wayne_2
    Wayco Wayne_2 Member Posts: 2,479
    Thanks for the replys

    guys. I've beeen using he Buderus G-115 with the Riello burner for my oil jobs. Hard to go wrong with that, but I just wanted to throw the question out in case I've missed somthing. I'm more familiar with gas and use the Munchkin when I can. I'd like to see the new Buderus condensing gas boiler. So many toys to play with and so few customers with boilers that need replacing. (; WW

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  • Constantin
    Constantin Member Posts: 3,796
    Thank you for your thoughtful comments!

    .. that narrows the field down to:
    • Buderus G115-34
    • Burnham Opus O1-90
    • Viessmann Vitola VB2-33
    • Dunkirk DPFO-4
    I had a lark calling Viessmann in the US some time back and asking the phone rep when they're planning on bringing the VitolaPlus to the US market. The rep didn't know what I was talking about (and that's OK, it's not sold over here).

    I explained the secondary HX to the rep and then asked whether Viessmann might offer it as a retrofit kit in the future (when sulfur levels are lower for #2 fuel in NA). Naturally, the poor guy had no idea either. On the other hand, what would prevent me from "smuggling" such a kit into the US? ;)

    Anyway, the chimney situation is aggravated somewhat by the horizontal distance to the chimney (about 10 ft from where the boiler will be installed) even though the exhaust tube can be installed at an angle of up to 30°. From the ceiling in the basement to the tip of the house (about the height of the chimney) it's another 35 feet. I'll forward your comment though to the contractor and see if the usage of ventinox+insulation solves that problem.
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