Mystery motor - heat component?


I have an approximately 415 watt mystery motor that I have not yet identified with certainty. I believe that it is a group of motors coming on at the same time related to heat. Heat is provided by a propane fired Weil Mclain GV propane boiler. There is a blower motor to bring in combustion air, two small Taco circulator pumps within the boiler cabinet, and five Grundfos circulator pumps outside the cabinet (two larger and three smaller). My best guess is that this “motor” is actually a particular group of some of these motors coming on at once. It’s too large to be a refrigerator or freezer and its run times don’t relate to my clothes washer, dishwasher, or dehumidifier. I’m out of ideas for other relatively large motors. And the run times are not consistent with heat and I cannot isolate this device by turning my boiler emergency switch off (it does indeed power down all of the pumps if I do it).


I’ll add that Sense has found what is definitely the ignitor for the boiler (approx 270 watt heat element that runs for 22 seconds and linked to boiler starting up)


Do you have a well by any chance, or a pressure boosting pump? That looks somewhat like a water pump signature to me - the way it runs in tightly clustered groupings. Unless it is missing a lot of runtimes, the time pattern doesn’t look right for a heat component.

If you really want to rule out heat, shut your boiler system off for a day (when it’s warm out) and see if the device runs during that time.


Thank you; we are fortunate enough to have superb low cost municipal water. There’s no booster pump; the only water pumps would be the disposal, the clothes and dish washers, the circulators, and the hot tub. The tub is not the type that is kept filled; it is a Roman tub that is just filled and used on occasional evenings and is shut down and dry the rest of the time. You can see why I’m stumped so far!


Sounds like your theory may be sound. Can you isolate one or more of the smaller circulating pumps (either electrically or mechanically) so they don’t actuate and see if the signature changes?


Thank you luterra and dgeist. I think that I’ll just let it remain a mystery. As for isolating pumps it’s not worth pulling apart wiring just to identify a device in Sense. Same for shutting down the system for a day - not likely with a house full of girls and women. The hot water is supplied from one of the boiler’s zones via an indirect fired water heater so we’d give up hot water to shut down for a day. Oh well, I’ll just have to let this one go for now.

closed #7

This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.