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Riello 40 Start-Up burnout??

Hilly Member Posts: 427
Has anyone ever witnessed a primary board burn out like such (see picture) on a Riello 40 F5 burner during initial start-up? I'd certainly like to troubleshoot this before attempting to fire a replace primary controller. This burner is piped with TigerLoop supplied with #2 Fuel Oil from a top outlet Roth Storage Tank. The burner is being controlled by a Honeywell L7248C Aqaustat. Not sure what other information I can provide that may help solve this issue. Thank you in advance for anyone that takes the time to read this, whether you have a solution or not I do appreciate your time.



  • Jamie Hall
    Jamie Hall Member Posts: 23,438
    Classic overheating. Something somewhere is either shorted or picking up voltage it shouldn't. Check all you wiring -- not just connections, but damaged insulation etc.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Hilly
    Hilly Member Posts: 427
    We were thinking a faulty ground or reversed L/N were the problem too. It was a friend's place. He is going to go through the wiring tomorrow. Could there be any other damage to look for or will he be able to replace the primary control and fire away?
  • Hilly
    Hilly Member Posts: 427
    Thanks Jamie, essentially I'm pretty sure you're also saying... Double check all the wiring. I don't believe anything else in the system was damaged so there may likely be a short in the line from the aqaustat to the burner. I just hope he'll be able to get a primary controller replacement.
  • BobC
    BobC Member Posts: 5,479
    Did anyone look at the top side of that circuit card to see what kind of damage occurred. If the area has power problems it might be wise to add some surge control on that circuit.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • icesailor
    icesailor Member Posts: 7,265
    edited January 2015
    Way back when, just after the Pleistocene Era, you could use a single pair of Romex as a switch leg, and not have a neutral on a switch box if the box was used for a switch that controlled an appliance. Like the safety switch for an oil burner. On new modern work in the 21'st century, you're supposed to tape the white wire with black tape, showing that it is a "hot leg" for the switch leg. And run two pairs of conductors to the switch. The whites are all the neutrals, and the blacks are the feed.

    Its always been my understanding that Riello uses a DC transformer so there must be some sort of rectifier circuit on that board. I'd be looking for some power on a neutral, getting in somewhere.

    I'd be starting with putting my Multi-Tester on some white wires to cold water pipe connections. See if I had any voltage on any neutrals. If the house service is fed with aluminum into the panel. and it hasn't been done in the last few years, I'd be having Sparky come and crank down on the buss bar terminals like I understand is supposed to be done with aluminum wired services. Aluminum wire expands and contracts.

    And be sure that you don't have any reversed polarity issues.