Output/Fan will not turn no matter what setting the speed control dial is on. Blue light and green light go on when humistat knob is turned. I purchased this humidifier in November and it was working just fine until last week. I have cleaned filter and water tank and base as per instructions in manual and still no fan. I think there is something wrong with the motor.

I would look at the floating switch actuator. It's common for the float to bind up in the holder which keeps it in place. If the actuator is floating free, then look at the switch itself. Could be corroded or otherwise malfunctioning.

They are talking about the Humidistat which is separate to the Humidifier. Turn the power off to the furnace and that will disconnect any power to the humidifier. Turn the water off to the Humidifier if you have to remove it from the plentum. Then go ahead and install your new evaporator. If you are looking for the humistat follow the T-stat wire and see where it goes from the water valve of the humidifier...... But they may not have installed one and are useing a different way to turn the Humidifier on in the heating cycle.....

Yes when you turn the dial on the humidistat 24 volts gets sent to the solenoid valve and it will click open and allow water to flow through it.

The higher the % of RH, (relative humidity), the more humid the house will be. I would disregard the temp part of the dial, and focus more on your comfort. Adjust it up daily until you reach a satisfactory humidity level. Hope this helps

There is normally a capacitor to prevent surges across the motor it might the short circuit.# and preventing the motor from starting.

the solinid may be stuck or the humistat is wired wrong

There is a 0 setting on the fan speed setting knob ...

There is a devise called a current sensing relay (a little black box that hangs on a blower motor wire that senses current from that wire) If you have such a devise it should hang from the white (common) wire. Loop the wire through twice.

Turn the control knob to the test/reset position untill the change water panel light blinks to reset the change panel timer. Make shure the furnace is running calling for heat.Turn control knob to prior setting after resetting timer. Hope this helps.

Make shure the 24 volts is hooked up to power that is only powered up when the blower is running. Some furnaces have a HUM terrminal on control (make shure the HUM is 24 volts some are 120 volts then you must use the transformer supplied with the AP 600). You can use a RP # 50 relay that senses current only when the furnace motor is running on the heating speed. Hope this helps