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Low water cutoff control module

Dave_23 Member Posts: 190
Hi there. A while ago, during a plumbing service call, I was advised by a contractor to consider replacing the McDonnell LWCO electronic control module attached to my LWCO probe. The reason given was "...it's good practice to replace the module every 10 years, even if it's still working..." I have a WM EG-35, steam trim, with a McDonnell electronic probe-type LWCO, all of which were installed new in 2001 by a very qualified steam plumber.

(Interesting note on the installation: My steam plumber gave me two options during the boiler installation: Pay full price for the install which included himself and a helper, or pay a discounted price, with me (homeowner) working as the helper and at the same time, learning about the system from an expert...I can't remember how many five gallon pails of skim I carried to the basement sink, btw...My steam plumber falls into the category of Master plumber with extensive experience in residential, commercial and industrial steam...Glad to know him...I chose the discount + learning opportunity)

Back to the original point, being of the mindset "if it ain't broke, don't fix it" I don't believe I should replace the LWCO module. Thoughts?


  • KC_Jones
    KC_Jones Member Posts: 5,431
    I just removed a perfectly functioning 32 year old probe type LWCO from my boiler (was doing a complete boiler replacement). I would agree if it ain't broke don't fix it. That LWCO should be pulled and cleaned and tested every year for sure, but personally I wouldn't change it "just because". Just another homeowners opinion. Oh and you have a very "cool" contractor to be willing to teach you and save you money at the same time. I admire you as a homeowner for wanting to learn! There needs to be more of us like that!
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,512
    This what McD Miller says

    Maintenance schedule
    • Maintenance and service must be performed by skilled and
    personnel only.
    • Replace probe when PFA insulator is cracked or worn or probe is loose.
    • Test the low water cut-off annually.
    • Remove and inspect the self-cleaning probe every
    five years

    • Use a non-abrasive cloth and rinse with clean water when the probe requires
    cleaning. Do not use sharp instruments to remove accumulations of rust or scale.
    • Replace probe every ten years.
    • Replace the low water cut-off control box every 15 year
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • KC_Jones
    KC_Jones Member Posts: 5,431
    Apologies I have a hydrolevel and they don't mention anything (that I could find) about replacement like that. Same basic instructions for cleaning and testing though. That is interesting though.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15