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Any Riello Experts?

BornForDying
BornForDying Member Posts: 40
I was out on a service call with a Buderus G115 with a Riello F3 a few days ago.

Unit was installed in the late 90s.

Unit was having an intermittent problem as follows:

Would run through pre-purge fine, and light. After 5-10 seconds, the flame would go out, but the motor would continue to run through a pre Purge cycle, after which the burner would re light. This cycle would continue.

Hate to say it, but between the other tech and I, we threw every part at this thing with no luck. Tested everything per Riello troubleshooting guide. Nothing.

Call up Tech support, he says without question, it's an issue with low sulfur fuel oil. Recommended an electrode adjustment, and fuel pressure increase of 20 pounds. Customer hasn't called back yet.

What's the deal here? Anybody have an understanding of why the low sulfur oil causes this problem, and why this fix works?

Comments

  • GW
    GW Member Posts: 4,544
    Hard to believe the oil is to blame but anything is possible

    Yes in the old days (your system is Old Days) jacking the pressure was the ticket. Now the G115s come cranked up. Not too many years ago it was set for 150.

    Are you lifting oil? Did you check vacuum? Excessive draft? Too much draft pulls the flame off the head
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • newagedawn
    newagedawn Member Posts: 586
    change the strainer
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,695
    edited January 2018
    Without knowing the rest of the numbers, I would check for too much air, then ohm out the coil for the fuel pump.
    Could also be very cold oil, or something in the fuel line. What was your vacuum number?
    steve
  • BornForDying
    BornForDying Member Posts: 40
    No lift on oil system. About 20 ft of 3/8 coated. Dual filtration. No reading on vacuum gauge at spin on filter. Customer has annual cleaning done where filters, strainer, and nozzle are changed. Always nice and clean. System is well taken care of.

    According to customer, issues started 6-8 years ago. I found out later NYS mandated the switch to ULSD in 2012.

    If the flame was going off on flame sense (lost flame) wouldn't it trip reset? This condition never does.

    Coil was within spec. Tried a new one just to be sure. No change in faulty condition.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,695
    I've been using/delivering/selling ULSD w/wo bio for at least that long, never had a problem. In fact I think things have improved-heat exchangers cleaner.
    I'm disappointed tech support would say it's the fuel, then tell you to adjust the electrodes, jack up the pressure. Did they spec a different nozzle?
    What were all your combustion numbers-draft (OF/OB), air/head settings, nozzle, pump pressure?
    steve
  • Jamie Hall
    Jamie Hall Member Posts: 18,977
    We've had a somewhat similar problem with a Carlin -- prepurge, start, 15 seconds, fuel cutoff. Run through the purge, restart and run just fine. Only did/does it once in a while. Never managed to actually catch it in the act. Never did figure out why...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,451
    Flame isn't stable when ignition drops out. Usually over aired or cold oil. Needs to be setup with analyzer
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    Grallert
  • Jamie Hall
    Jamie Hall Member Posts: 18,977

    Flame isn't stable when ignition drops out. Usually over aired or cold oil. Needs to be setup with analyzer

    That's what we figured. Been over the whole thing with a fine tooth comb, good analyzer readings (one of the experts on the Wall does that for me). Still puzzled...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,024
    Maybe a slight suction leak. Burner lights the first time but has some slight foam or air, shuts off recycles and has solid oil the second time around just a guess.

    Maybe check flame signal or cad cell resistance on a cold start and see if it changes when it warms up
  • rick in Alaska
    rick in Alaska Member Posts: 1,362
    I bet this is direct vent? The only time I see this happen is with this setup, and a concentric vent. If there is s slight wind, the combustion air intake draws the exhaust right back in, and since the riello responds so well to a lack of flame, it flames out and goes right in to recycle.
    If this is the case, all you can do is run separate exhaust and intake lines with better separation on them.
    Rick
  • BornForDying
    BornForDying Member Posts: 40
    Chimney vent. FYI, still no call back after the tech support recommended adjustments.