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Weird ?

RayH
RayH Member Posts: 98
A recent service call I went to the customer claimed that the boiler would fire for about 4-5 seconds then shut off. Shortly later it would come on and run normally. He said it has been happening since it was installed about 5 yrs ago. It is a Pensotti oil boiler with a Riello burner. Hydrolevel Aquastat set to 160 - 180 on the limit. Taco 501 relay. I checked all the wiring for loose wires. Made sure the pump pressure was at 170 psi. Bleed the system for any air in the line. I found nothing wrong. He always had heat and the boiler worked fine the entire time I was there. The customer was curious and so was I. Any ideas out there ???

Comments

  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    edited March 2018
    Assuming you checked all factory settings and are close to the original set up, might be too much combustion air. What were combustion numbers, draft, and smoke number?
    Could also be a slight vacuum leak, going into recycle on first fire, then running ok.
    Did you ohm out the coil? Check terminals 1 & 2 for 1350 ohms +- 10% (1215-1485 ohms).
    You could also just pop in a new cad cell eye.
    Do you have a Riello service card? Just follow the flow chart. Seems like 99% of the problems that don't have a proven source (electrically with your VOM end with "replace the control box".
    steve
  • ratio
    ratio Member Posts: 3,616
    Did it come back? If not ya fixed it.

    I can fix things like that too. In fact (literal fact, not hyperbole) I can fix things like that over the phone—just calling me makes it better.

    No lie.

  • kcopp
    kcopp Member Posts: 4,419
    Taco zone valves?
  • A "delay on make" relay that powers the pump to prevent boiler condensation? Like a car thermostat.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • newagedawn
    newagedawn Member Posts: 586
    bad t stat wire, shorting out
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
  • DZoro
    DZoro Member Posts: 1,048
    I had a R8184 control do the same earlier this year. Not sure what control you have. Also had the "new electronic control" do similar thing on another system, but that turned out to be the old T87 stat.
  • MartinBarry
    MartinBarry Member Posts: 2
    If the burner ran of 5 sec's, this did not have time for the primary safety control to energize, I would be looking at the t-stat, or other wiring most likely the low volt side.
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    edited March 2018

    If the burner ran of 5 sec's, this did not have time for the primary safety control to energize, I would be looking at the t-stat, or other wiring most likely the low volt side.

    Huh? It's a Riello burner, that's not how the primary works.
    DZoro said:

    Not sure what control you have...

    It's a Riello burner.
    steve