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Help with timing device for a humidifier.

innocent victim

New Member
I have a small humidifier that I use during the winter. It works well, except for one thing; when it reaches the humidity set point, it cycles on and off and on and off and on and off and so on. It's VERY annoying! I would like to put in a small circuit that will sense power in the neutral leg of the motor, and then open that leg for, say, five minutes and not allow it to come back on again until the timer times out. Building this circuit will be easy for me, but designing it is beyond my capabilities. I'm thinking just a way to sense the power, perhaps with a coil of wire around the neutral lead of the motor, and then a 555-based timing circuit and a relay. All I need is a schematic, and I'll take it from there.
Anyone able to help a guy out?
 

gophert

Well-Known Member
Most Helpful Member
Can you take apart the control humidistat? It may be possible to just add a little positive feedback - depending on the type of the sensor.
 

gophert

Well-Known Member
Most Helpful Member
Post a photo of the humidistat circuit if you can easily get to it. Don't take apart any sealed up potting that keeps the humidistat safe from users if any exists. We'll just go your route with a timer.
 

innocent victim

New Member
Can you take apart the control humidistat? It may be possible to just add a little positive feedback - depending on the type of the sensor.
I can't do so without seriously damaging the unit. It's not exactly tinker-friendly, like so many things these days. I should have mentioned that the sensor is on the line cord for the unit. I don't want to interrupt anything there, as doing so would entail resetting the control electronics each time it interrupted, i.e., I'd have to reset the humidity level, power level, etc.
 

innocent victim

New Member
I'm not sure, but from the name, it sounds like it might. I'll have to take another look at your link in the morning; I was just headed for bed. Thanks!
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
Without it, it blew fuseholders to bits on a power glitch. Thermostats now have it built in. This was a mechanical thermostat on a whole house AC.
 

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