Examined unit. Checked all wires for wear and burns. All good. checked inside box with heat and humidity elements and found axial fan burnt. Connection burnt as well. Will order part for repair. Note: Left unit unplugged and advised. 3-24-17 Replaced fan in unit. When doing so bulb broke off thermostat for air heat. Made temporary repairs to get customer in service. 4-10-17 Disassembled and found new control looked different than the existing one. Called Hatco to confirm I had the correct one. Replaced thermostat, filled with water and tested. Both air and humidity controls work. Reassembled.