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electrical interference

Steve Ebels_3
Steve Ebels_3 Member Posts: 1,291
I probably would have replaced the transformer first.

PS: AFTER checking all the grounds, all the way back to the box.

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Comments

  • Bill_55
    Bill_55 Member Posts: 11
    electrical interference

    I have an oil-fired WeilMcLain hot water boiler (around 100,000 BTU's) that I use to heat my home (baseboard heat) as well as to preheat domestic hot water before it goes to my electric water heater. The unit is pushing thirty years old but looks like new.

    My problem is that when the aquastat calls for the burner to fire, before the firing takes place, you can hear a hissing noise in the aquastat. It lasts for several seconds and sometimes stops and starts again before the burner fires. At the same time as the hissing noise, there is electrical interference through the entire house on all circuits in the form of static on cordless phones and on older television sets. This can last from a few seconds to twenty or thirty seconds as which point the burner fires and the noise and interference stop.

    The burner is on a separate 15 amp circuit and all wiring on that circuit is new except the cable to the emergency switch at the top of the stairs. I have a 150 amp service, CH breakers, and have no trouble with any other appliance. I've had this looked at by at least four service techs and no one can solve the problem. In the course of the last two years, the following parts have been replaced: triple aquastat, burner motor, primary control, thermostat. There's not much left to replace except the transformer and the electrodes.

    Any thoughts on this problem?
  • Dick Carlson
    Dick Carlson Member Posts: 13


    jumper across the T-T. If the problem goes away, it's external (end switchs/T-stat).
  • Bill_55
    Bill_55 Member Posts: 11
    to Steve re transformer

    I've wondered about that but the techs keep saying the transformer is fine. One replaced the primary and the aquastat on a no-heat call; the burner motor was replaced by a tech who thought there might be a dead spot in the motor.
  • Bill_55
    Bill_55 Member Posts: 11
    to ****

    I should have added that this happens as often or even more often outside of the heating season when the thermostat isn't calling for heat but instead, the aquastat is calling for the burner to fire because the temperature in the boiler is low, either due to heat loss over time or due to water flowing through the domestic water coil. That rules out the thermostat, doesn't it?

  • steve_93
    steve_93 Member Posts: 37


    Had the same thing happen recently, found to be the electrodes arcing to ground.

    Check them and see if there is any burn spots.
  • Randy_12
    Randy_12 Member Posts: 9
    control

    Replace the aquastat control(Probably a Honeywell L8124A), that will fix the problem.
  • J.C.A._3
    J.C.A._3 Member Posts: 2,980
    Bill,

    In my experience, I've seen the micro-switches in the "block type" aquastats cause this many times...but have also found the transformer to be the culprit a few times.

    The newer high voltage transformers a bit more so than the old iron core models, but rarely. I'm going to impart a bit of wisdom that was given to me when I first started....It's the GREEN wire dummy! Check all grounds from the panel to the boiler and burner, and make sure they are both tight and in the proper place. Chris
  • Dick Charland
    Dick Charland Member Posts: 178


    Replace the aquastat, probably an L8124 control, the contacts aren't making cleanly in the block. Usually it acts very intermittently and is difficult to catch.
  • Rusty Powers
    Rusty Powers Member Posts: 30
    My Vote

    is the transformer, it's the newer solid state style right?
    We've seen it once in about 20 years of service work. Doesn't it feel good to be pre-disastered?
  • Steve Ebels_3
    Steve Ebels_3 Member Posts: 1,291
    Here's another one..........

    We have an undercounter Sony AM/FM/CD player in the kitchen. A few days ago I noticed it buzzing when I was getting some iced tea from the frig. The wife had it on one of her favorite stations, 88.3 FM. I realized that the buzz quit when I shut the frig door. Playing with it a little further revealed that when the light was on in the frig, the radio buzzed. It's a standard incandescent 25W appliance bulb. I also determined that it buzzed only on that particular radio station.

    Now here's the wierd part. Later my wife came home and I was going to duplicate this for her. Turned on the radio, set to 88.3 and opened the door. Nothing, just music. While I was standing there getting one of those "Sure honey, and pigs fly" looks, the compressor in the frig turned on. The bloody thing started buzzing like all get out. But if I closed the door or manually turned off the light it wouldn't buzz even if the compressor was running.

    So now my wife doesn't think I'm quite so badly demented any more and I know that on 88.3 the radio buzzes when the light in the frig and the compressor are both on.

    Other than that, I am stumped for an explanation.

    Got any?
  • Tom M.
    Tom M. Member Posts: 237
    I agree with Randy.

    If it's before the burner starts, I suspect the low limit contacts. If it's during the run, I suspect the transformer or the primary.
  • Dick Carlson
    Dick Carlson Member Posts: 13
    To Bill

    I have seen aqua stats on hot water makers make cleanly and cause chattering relays. Phase 3 comes to mind.
    ****
  • Dick Carlson
    Dick Carlson Member Posts: 13
    To Bill

    I have seen aqua stats on hot water makers make cleanly and cause chattering relays. Phase 3 comes to mind.
    ****
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