Low water boiler cutoff help


Old 10-25-17, 08:09 PM
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Low water boiler cutoff help

My low water cut off says there is low water but there is water. I cleaned the probe on my guard dog Mcdonnell & Miller 24 v.a.c lwco, replaced it and still shows low water. I just bought the house so I'm not sure about the maintenance of it and was wondering what needs to be done.

Last edited by PJmax; 10-25-17 at 08:29 PM. Reason: added more text
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Old 10-25-17, 08:30 PM
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Welcome to the forums.

I brought your info over from your PM to me. I'll need to look up your cut off system and possibly someone will jump in too with further help.
Old 10-25-17, 09:01 PM
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What is the model number of the LWCO and is it a manual or auto reset. Do you have a water feeder or do you do it manually.

You indicated 24V so that tells me you have a gas boiler and not oil.

When you say you have water, what is the level. Is the water over the probe.
Old 10-25-17, 09:39 PM
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Replace it... They go bad ..

You can bypass the wiring to get the boiler to run. ( often the two yellows to where its connected to interrupt the circuit...

Is it the 120v model or 24 v model

Old 10-28-17, 04:29 PM
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Those old MM low water cutoffs get full of mud, and they have to be opened and cleaned out once in a while, and of course blown down once a month.

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