Weird noise from thermostat

My garage has a studio with electric baseboard heat in one room and an electric wall heater in the entryway. It's expensive to run - something like 22 kW - so I mainly use that room in warm weather.
The entryway thermostat is an "Electromode Model M7-D double line break" with a huge bimetallic strip. At random intervals, a kind of screeching/hissing sound comes from it. (At least, I think that's where it comes from. It never happens when I'm right near it.) I pulled the double breaker than powers the baseboards, and turned the thermostat built into the wall heater all the way down. So there shouldn't be any current flowing, right? So where does the noise come from, and can I do anything about it w/o cutting wires?
Thanks!
Theo
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Your info is a little sketchy. Does the wall thermostat control all the heat? Is there only one breaker that feeds all the heat? The wall heater most likely is not 22KW, but probably has a blower in it, which could squeal on occasion. It's also possible that bad contacts in an electric heat line voltage thermostat, could make a hissing sound when closing. If so, I'd have it replaced.

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"RBM" wrote:

squeal
have
Sorry about that. As far as I can tell, that thermostat only controls the wall heater, which is a fan unit - probably 2 kW or so. The thermostats that control the big baseboards don't seem to squeal.
I actually need to keep that wall system working in the winter to keep some pipes from freezing, or I'd just disconnect it. If it might be the thermostat contacts, I'll try cleaning them with a point file or emery paper, or just replace the unit. BTW, the sound lasts about 3-5 seconds, and sounds like sandpaper on metal.
Thanks-
Theo
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That actually does sound like a bad thermostat. The bi-metal plate should bend slowly, then quickly snap the contacts closed or open. If it doesn't snap, but slowly closes its contacts, it'll hiss and spark at the point that they begin to make contact

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Theo wrote:

I would guess the contacts are burnt and you will need a new one.
--
Joseph Meehan

Dia duit
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