Thermostat/AC Won't Turn On - in FL!

[buck]

Hi,

We have a Ranco J10-821 Humidistat installed between our thermostat and the central a/c.

Usually, it's set to around 40% which means that if humidity is less than 40%, there is no power to the thermostat and the screen is blank. If humidity rises above 40%, the thermostat gets power and turns on the a/c.

This afternoon the a/c was running and running and the humidity was at 40% so I turned the humidistat down the tiniest bit and the ac turned off. That was fine. BUT since then, we can't get the a/c to turn back on. We can't get power to the thermostat - screen is blank.

No circuit breakers were thrown but we switched them off and on again for good measure and still nothing.

I've turned the humidistat all the way down which means the thermostat should just be on constantly and it's not.

I don't know what to do at this point. The humidity and temp level is rising in the house and it's getting uncomfortable.

Please help?

Thank you.
Buck
PS I've checked all over the internet for an instruction manual hoping to find there is a reset button or something and have found nothing.

[buck]

<update>

Midnight. Had to call A/C company - found thermostat to be dead (exactly 5 years 30 days after purchase w/5yr warranty). Replaced with new one. $280 later... A/C is back on and humidity has dropped from 60% to 40%.

[HayZee518]

since the humidistat is in series with the thermostat, next time just jumper out either device to see which one affects the circuit. this will be your bad device.