| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric floor heating system for preventing the abnormal temperature rise of the surface of a floor which may occurs during continuous energization for a long time by lowering a duty factor and for preventing the temperature rise of the floor, not intended by a user, during operation in the condition of lowering the duty factor when the user changes a floor heating level to be lower. SOLUTION: When operation in a normal operation mode continues for a long time of four to eight hours, a control circuit of a controller 20 automatically reduces the duty factor by 5% or 10% or so at a time when a predetermined time passes. Under operation circumstances where the duty factor is automatically reduced, when the user selects an duty factor which is lower than an duty factor previously selected with the operation of the controller 20, if the selected duty factor is higher than or equal to the duty factor during operation, a means provided for the controller 10 does not change the duty factor into the selected duty factor. COPYRIGHT: (C)2007,JPO&INPIT
|
