I'm running an application with an industrial heater, basically you
apply 120V to the unit, it blows hot air. I've built a 24VAC relay
controlled by a smart thermostat so that the thermostat powers on and
off the unit.
The Issue I have is that I think there's a dead spot on the blower motor
of the heater, so about 1/20 times, the heater won't start when 120v is
applied. If the power is cycled on and off a few times, then the motor
will start. The unit is smart enough that it won't start the heat if
the fan isn't running, but the thermostat isn't smart enough to know
that it's not actually heating and cycle it.
I can tell when the unit isn't running because I have a temperature
probe on the output air of the unit, and when it drops below ambient
temperature, I know that the Louvers drawing outside air are open, but
there is no heat being produced. Then I can Manually go in and cycle
the thermostat on and off a few times, and the unit will start working.
I'm trying to figure out a way to automatically cycle the unit if a
temperature reading is below a set point. It would need to be something
programmatic, like
IF Temperature is Below SETPOINT for longer than 4 minutes, THEN CYCLE
power for 5 seconds, REPEAT.
The blower motor does draw about 1600W, so a 120v relay needs to be at
least a 20A relay, a low voltage switch interrupting the 24VAC would be
easier.
I was wondering if something like this already existed. I could
read/switch based on temperature from a packet flux, but I don't think I
can do the timings without external scripts. Would this be simple with
an Arduino? I've never used one before.
I hope the collective might point me in the right direction to start
looking.
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