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ps801-24 lwco not sensing low water

hi on a new residential slant fin steam boiler i cant get the lwco to react to draining the water out of the boiler. if i take the probe wire off the red light comes on and boiler shuts off and feeder feeds. i have replaced unit and probe and same condition happens. cant leave people with heat while this condition continues any help alan


  • Steamhead
    Steamhead Member Posts: 16,714
    Is it possible

    there's some dirt inside the boiler that's shorting the probe out?

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  • alan simon
    alan simon Member Posts: 4

    boiler has been flushed for about 100 gallons in and 100 gallons out but condition remains alan
  • Boilerpro_3
    Boilerpro_3 Member Posts: 1,231
    I have found

    that often times the splashing of the water around in the boiler keeps the boiler running when the water is much lower in the gage glass. And this is in clean boilers... Ever notice how much higher a probe type lwco is located on a boiler than the same boiler with a float type? There is often several inches difference. The thing I always check is to make sure the boiler shuts down before the water reaches the minimum safe water level...usually just above the bottom of the gage glass but sometimes lower. this is generally lower than the probe.

  • Alan

    If you have already changed the complete control and it is still doing the same thing, I would suspect that the control may have a wire swapped around on the harness to control connection or that the polarity of the incoming voltage may be backward.I would start with the incoming polarity first and then trace the wiring using their I&O manual. Hope this helps.

    Glenn Stanton

    Manager of Training

    Burnham Hydronics

  • alan simon
    alan simon Member Posts: 4

    i drained the total water from boiler after first putting the gas valve topilot
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