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RBM
 
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Default Weird noise from thermostat

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



"Theo" (reply w/o spam) wrote in message
...
"RBM" wrote:
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.


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