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LWCO and feeder maintenance

jw1848hjw1848h Member Posts: 8
I have a 10 year old steam boiler, with 24v McDonnell & Miller LWCO and automatic feeder. The only routine maintenance I had been doing is weekly draining the sludge, the installer did not tell me about the recommended annual cleaning of the water feeder filter. This winter the boiler overflowed, I presume due to a speck of dirt or similar in the water feeder valve and the water trickled into the boiler and eventually the mains and through the air vents. I will be replacing the feeder. I am now aware of additional manufacturer recommended maintenance: Inspect the LWCO probe annually and replace every five years, replace the complete LWCO unit at fifteen years, and replace the complete water feeder unit at ten years. My questions are: 1) when someone in the trade comes across these, does anyone actually routinely replace these parts at these intervals, or do they only get replaced when they fail? 2) Does anyone really routinely inspect the probe? 3) I tried removing the probe with a monkey wrench and a pipe as an extension, but couldn’t. Any reason I shouldn’t use an impact wrench to remove it?


  • PrecaudPrecaud Member Posts: 311
    24V is the voltage. What's the actual model number?

    1950's Bryant boiler in a 1-pipe steam system at 7,000 ft in northern NM, where basements are rare.
  • jw1848hjw1848h Member Posts: 8
    LWCO is PS-802-24, feeder is WFE-24
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 7,058
    Yes, you can use an impact if you have a new probe handy.

    Low water cutoffs should be serviced yearly. Other than that parts usually only get changed when they fail
  • jw1848hjw1848h Member Posts: 8
    Thanks. I won’t replace the probe which works fine, I’ll just inspect it annually, starting now, using an impact wrench to get it out. Hopefully subsequently it will remove more easily. But a couple of new questions pop up: by “inspecting” it what exactly am I looking for on a unit that works; what could I find that would make me want to replace it? Maybe I should rinse off the tip in clear water, or maybe soak in CLR to remove any stubborn rust?
  • gerry gillgerry gill Member Posts: 2,977
    We do pull, inspect, and clean the probes annually. We will use an impact wrench if our 3/4” drive ratchet can’t handle it.

    We only push the time interval replacement if the units really in nasty condition. Otherwise we just inform the customer.

    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • jw1848hjw1848h Member Posts: 8
    I actually read the boiler manual, and found the probe inspection and cleaning procedure: "inspect for scale and sediment buildup," "remove light deposits with damp cloth soaked with vinegar," and "remove stubborn deposits using diluted phosphoric acid"

    Attached is a picture of the probe, after simple rinse with water. Looks pretty clean to me, it's even shiny under what I think is the "self-cleaning" dohinky at the tip. Is it safe to assume that this is just fine, no need to replace now (or maybe never so long as this clean condition is maintained) even though it has reached the manufacturer's recommended ten-year replacement milestone?

  • gerry gillgerry gill Member Posts: 2,977
    It looks pretty good. I would just recommend cleaning to a shine the section of probe shaft between the insulation and the spin cleaner. Technically not necessary but advisable.

    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • jw1848hjw1848h Member Posts: 8
    Can't hurt, I cleaned it with steel wool. I also soaked the tip in CLR for a few minutes, now the entire length is clean.

    Thanks to those who responded.
  • dopey27177dopey27177 Member Posts: 299
    Use chemical boiler water treatment and you will never collect sludge in the lwcf or see dirt on the probe.

    Been out of the business 20 years so I can not tell you what the boiler water chemical is.

    I used to use steam master but it is no longer available.

    When using any chemical in the boiler it is a bit tricky.
    Usually the instructions are a bit over kill. Use about half of what is recommended and test for PH. PH should not exceed 9.

    My recommendation is to use a chemical that colors the water.
    Steam master colored it blue or light purple. When the color disappeared t was time to drain the boiler and install new water and chemical.

    I did my own home once ayear.

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