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Report on Savings w/ Buderus G-115 After One Year

Weezbo Member Posts: 6,232
And increase the stack temp slightly and or the return water temp...you would have even better numbers plus the equipment will live longer.

Trust me on this one *~/:)


  • D107
    D107 Member Posts: 1,852
    The Wall was a big help with this

    Well I have good news to report after one year of operation of new Buderus G-115/21 boiler, Riello F3 40 burner, R2107 control, ST-150 HWH, 5inch stainless steel chimney liner and Roth 275 gal tank.

    Including Degree Day adjustments, overall savings total usage: 36% or 461 gallons.

    Prior setup was:
    1975? Hydrotherm Boiler Model 0A 154 Aquarius, 1.10 GPH (154K btu firing rate), Gross DOE Output 116.8Kbtu/hr, Net Output 101.7KBtu/hr; 1965 Tankless HW HX Taco 2004T gravity flow into 66gal stone-lined John Wood tank with Watts Mixing Valve

    Prior System Total Annual Usage was: 1254 gallons.
    DD per oct 25-05 to oct 25-06 = 4626

    New system used Total 784 gallons
    DD per oct 25-06 to oct 25-07 = 4527.
    Heating only 662gal/4527 DD = .146DD/gal (hope I divided correctly).
    HW use 16% = 122 gal

    Obviously as the oil prices rise, dollar savings become even higher with the fuel savings. Saving 461 gal this past year at an average of about $2.534gal = $1168 savings. At $3gal, it will save almost $1400.

    Of course it's hard to truly compare apples to apples. Had the old boiler/burner been fully maintained over the years it might have been 10% more efficient but that could be easily negated by future high maintenance costs.

    At .60gph firing rate, if the burner fired 24/7, it would use only 14.4 gal/day. I doubt it ever used more than 10 gallons a day probably less--even when temp was in the single digits, so that means to me it's 30-40% oversized even though it's Buderus' smallest oil-fired unit. So many contractors recommended much larger units. The difference between the 47K heat loss and 77KDOE output (slightly overfired) is almost 40%. If back porch temp was kept at 70 instead of 64, that would show a slight usage increase. Since cycling tends to be on the short side, I believe a buffer tank would be a benefit.

    1-Due to pumping away, a few rads now get fully hot that were sporadic before.

    2-Problems: Roth suction line got plugged. Tubing was replaced, and tiger loop was added and pump pressure raised 10 psi to 155. Ok since then.

    3-Could have saved more if R2107 had morning boost could keep curve lower. R2107 setting was Offset 2, 74 daytemp, 63 nighttemp; main zone t-stat set for 72 day and 63 night. 2nd zone T-stat c (unused porch) set for constant 64.

    4-See attached photo of soot and ash on inside of firebox at annual tuneup. Much of that probably came from that suction line problem. I'd say loose ash totalled about 1-2 quarts volume.

    5-This is a two-filter system, one at tank, one 10 micron at burner.

    6-Buderus and Riello tech support was a big help. I do wish a lot of the tips and advice that has come out online would be incorporated into an updated manual.

    I thank the Wall for all the advice, for helping to find the installer and for followup for later adjustments.

  • great news

    great news on the saving david except that boiler looks awful dirty with all the oil fired buderus that i have installed i have yet to see one that was set up and running correct look that dirty even after more thenm a year running peace and good luck clammy
  • D107
    D107 Member Posts: 1,852
    yes, burner setup could be better

    I am hoping that the dirt in the photo arises from the plugged suction assembly that occurred last February and the need to raise pump pressure from 145 to 155. Burner had trouble going from pre-purge to full fire. Alot of carbon in the endcone if I have my terminology right.

    Aside from that, I will have to make an effort to get the company's service dept. to re-tune to raise stack temp from 300 to 350. On original install the baffles had to be taken out to reach the 350; then they were put back in after the burner repair. It's not easy to find the two-hour annual tuneup out here.

    Thanks Weezbo and Clammy for your replies,

  • Robert O'Brien
    Robert O'Brien Member Posts: 3,541
    Nice to hear

    some actual field results.I've had better results leaving the baffles in and increasing firing rate to get the stack temp up to acceptable levels

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