SYSTEM FOR AUTOMATICALLY STOPPING TRIAL HEATING OPERATION

PURPOSE:To enable water to be fed to an entire heating water circulation circuit by a method wherein a water level in an expansion tank is detected, a timer starts to count from a time when the water reaches a set water level, the water level more than the set water level is kept continuously and as the set time elapses, the heating trial operation is automatically stopped. CONSTITUTION:In the event that a heating trial operation switch is not turned on under a heating trial operation mode, water is filled in a heating water circulation circuit under a heating trial operation, a water level in an expansion tank 6 is increased, the water level within the expansion tank 4 is detected by a water level sensing switch 6 and a timer starts to count from a time when the water level reaches a predetermined set water level. As a water level within the expansion tank 4 is kept continuously at a level exceeding the set water level and as a predetermined set time T elapses, the heating trial operation is automatically stopped. As the water level within the expansion tank 4 is decreased lower than the set water level, the counting in the timer is stopped and then the timer starts counting from the time when the water level newly reaches the set water level.