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low water cutoff

tmc Member Posts: 12
Anybody having problems with McDonnell miller pse 802 probe type low water cut offs? installed 4 burnham independence steam pin 4 and pin 3 boilers and all are shutting off on low water when there's plenty of water in glass. I removed probes which all looked clean but wiped them off anyway, reinstalled and still had same problem. Boiler will fire for about 1 min low water red lite will flash boiler will shut down, water level rises from condensate, boiler fires and then repeats cycle. Once again, this happens with water level above probe.


  • Through a glass emptily

    Could the initial cutting oil+ return rust have clogged the gauge-cocks, so the glass is not showing the true level? A new install has a lot of junk floating around in the system.

    Could the probe be electrically insulated with Teflon tape?--NBC
  • MDNLansing
    MDNLansing Member Posts: 297

    Ditto NBC. Make sure the probe is grounded (no tape on threads). Been there, done that.
  • tmc
    tmc Member Posts: 12
    low water cutoff

    doubtful guage cocks are clogged, this happened right from initial start up, but i'll check it out. As far as Teflon on probe as I mentioned on last post they were cleaned.I have a feeling there may have been a bad batch of low water cut offs. any other ideas?
  • Dirty power?

    Those probes are so electronic. Could there be a power problem: bad grounds, etc?--NBC
  • JStar
    JStar Member Posts: 2,752

    Make sure the factory jumper is screwed down tight. Check the other wiring connections as well. I've had a loose jumper from the factory before. It would run for a minute, then rattle loose and shut down.
  • tmc
    tmc Member Posts: 12
    problem solved

    replaced low water cutoffs with new ones, all 4 boilers working perfectly.
  • BobC
    BobC Member Posts: 5,470
    Good to hear

    Did the counterman say anything about a defective batch?

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
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