The effect of the defrost thermostat is to control the heating temperature of the heater. Through the defrost thermostat control refrigerator freezer inside the defrost heating wire, So that the refrigerator freezer evaporator frosting will not stick, To ensure that the refrigerator freezer to work properly. There are bimetallic and mechanical defrost thermostats.
    Through the temperature control tube to detect the temperature inside the refrigerator to control the compressor start and stop, So that the refrigerator temperature control in a certain range so that the refrigerator to normal use(All the refrigerators have a thermostat).  Defrost timer:Through the computer board memory chip or mechanical gear timing to control the refrigerator freezer inside the defrost heating wire work, So that the refrigerator freezer evaporator frosting will not stick, Leaving the refrigerator freezer to work properly (only air-cooled refrigerators have defrost function).

The thermostat can set the defrost temperature range;Also said that when the refrigerator temperature is lower than you set the temperature, The defrost relay closes and begins to defrost. For example,  you set the defrost temperature to be -15 ° C, When the temperature of the refrigerator is below -15 ° C, Start defrosting.

Of course,  some of the thermostat is based on the thermostat or compressor accumulated working hours began to defrost, That is,  defrost cycle T1, The defrost period T1 can be set by the user. Such as 6 hours,  10 hours.

  When the refrigerator to the defrost, The lower part of the evaporator heating tube to heat, Start defrosting. After the ice on the evaporator is melted, Will flow along the following water pipes, To reach the bottom of the water tray, When the evaporator temperature reaches zero about 8 degrees, Defrosting stopped. Will not produce water vapor, But defrosting due to a little longer downtime, The temperature inside the box will be slightly increased, But the overall performance of the refrigerator has no effect.