18FOR PREPARATION OF HEATING("HOT KEEP")"HOT KEEP"is operated in the following cases.When heating is started:In order to prevent blowing out of cool wind, the indoor unit fan stoppedaccording to the room temperature which heating operation is started. Waitfor approx. 2 to 3 minute, and the operation will be automatically changedto the ordinary heating mode.Defrosting operation (in the heating mode):When it is liable to frost. the heating operation is stopped automaticallyfor 5 to 12 minutes once per approx. one hour, and defrosting is operated.After defrosting is completed, operation mode is automatically changedto ordinary heating operation.When the room thermostat is actuated:When room temperature increases and room temperature controller actu-ates, the fan speed is automatically changed to stop under low temperaturecondition of indoor heat exchanger. When room temperature decreases,air conditioner automatically changes over to ordinary heating operation.WARMING OPERATIONHeat pump type warmingDefrosting operationAtmospheric temperature and warming capacityPeriod of warm-upWith the heat pump type warming, the mechanism of heat pump that concentrate heat of outdoorair with the help of refrigerant to warm the indoor space, is utilized.When a room is warmed with a heat pump type air conditioner, frost accumulates on the heat ex-changer of outdoor unit along with the drop of indoor temperature. Since the accumulated frost re-duces the effect of warming, it is necessery to automatically switch the operation to the defrostingmode. During the defrosting operation, heating operation is interrupted.Warming capacity of heat pump type air conditioner decreases along with thedrop of outdoor temperature.When the warming capacity is not sufficient, it is recommended to use anotherheating implement.Since the heat pump type air conditioner employs a method to circulate warmwinds to warm the entire space of a room, it takes time before the room tem-perature rises.It is recommendable to start the operation a little earlier in a very cold morning.