Report "I have had a new honeywell humidifier installed. The problem is the control H8908B. HE INSTALLED IT FIRST TIME ON A DUCT RIGHT NEAR THE FURNACE AND IT FEEL OFF . Melted . Then came in and moved it away from the furnace but still on a heat vent and the same thing happened 2 days later. It appears that it should go on a return duct upsream from the humidifier. Can it also be mounted on a wall. By just felling the ducts when the furnace is on can I tell which is the return air duct ? Thanks for your time and as you can tell I am not very mecanical Jim Phelan"