An orange light keeps appearing on the off and on switch, what does that indicate? How can I make it go away and get my humidifier to work again?

If this is an ultrasonic humidifier, in the bottom of the humidifier is a little disk that vibrates to turn water to vapor. This gets covered in mineral deposits and won't vibrate properly. They usually suggest something like vinegar to clean it. I found that this didn't work for me. What did work was cleaning it with my Waterpic on the highest setting. It chipped away the deposits and allowed it to work. HOWEVER, once you get it running again, buy the slant fin mineral absorption pads to keep it running. If you have mineral-rich water like me, you'll go through them quickly, but you also won't have white deposits on your walls anymore.

It's not uncommon for duct work in an older home to Bang as the furnace cycles due to age. The humidifier banging while turning on and of is mostlikely the solenoid valve; if the solenoid is bad it is actually to your benefit to replace the entire humidifier as the solenoids are very expensive, 50%+ of a new humidifier. Plus you get the 5 year parts warranty on the new unit instead of just one year on the solenoid. If you don't want to replace the entire unit you can replace the Humidistat, and that should fix the on/off cycling, however a new humidistat is included with a new unit, which again is more cost effective. They are easy enough to replace as a do it yourselfer, especially when replacing an existing unit. I hope this helps you.

There is probably a calcium buildup in the lines from the tank to the humidifier. You will need to take it apart to lean it. 50/50 White Vinegar should do the trick, Then flush the system with clean water, before using it as a humidifier again. In the future try using Bottled Spring Water or Distilled Water instead of tap water. Especially if your source of water is a well.

First off, you should not have lime buildup if you used distilled water and NOT TAP Water. If some build up occurs, cleaning should be done using VINEGAR solution. Check the float valve and gaskets. Replace any filters. Clean nozzles or exit ports where mist is spewing from.
These units are low cost devices and repairing them is not economical.

Turn it off for a few minutes then turn it back on. If it it works for a short time then turns orange again you need to clean the heating element. It will have a brown crust that builds up over time.

From the troubleshooting section of the manual (http://www.crane-usa.com/manuals/HumidifierManual2008.pdf):
Problem Humidifier power light is staying red and not turning green Humidifier is working than stops: ? Solution Ensure that water level sensor is assembled properly. ? Clean water float ? Call service center and request replacement water float ? If humidifier does not work at all: ? Ensure it is properly plugged into a power outlet. ? Check that the switch is in the ON position. ? If Power On indicator light does not come on, bring to authorized service station.

Turn the unit off, lift the fan assembly off the base, and push the connector together that goes to the float switch on the bottom of the fan motor. If you hold the switch in with your finger (careful not to get into the fan blades) and turn the unit on, the F indication should go away. F (as in Fill), apparently, means the base has no water. The plastic tube that sticks up out of the base floats on the water and pushes the switch. Put it back together, it should work!

Poor design, buy a different brand, I have owned two, they are junk.

Is there a manual on were prces go

The water sensor is a float in the mister area of the base. The float is off in one corner with a little plastic barrier around it and translucent cap over it. Make sure the float can more freely. If the float can move up and down but the light stays on, the reed switch (a switch controlled by a magnet built into the float) inside the unit might have been knocked loose, damaged or disconnected. The switch is actually inside the post that the float slides on, but it can only be accessed from the underside - inside the unit.