Electric heat popular on the unfreezing of the low-temperature evaporators. Heating coils are installed in the evaporator, around him, or in the refrigerant passes. One method uses a wire resistance heating elements are mounted under the evaporator, under the drain pan and drain pipe. The timer stops of the refrigerating unit and closed in the liquid line. Then he pumps refrigerant from the evaporator. Then, fans and heaters are turned on.
Heaters melt the frost from the evaporator and the water flows. Evaporators was warm enough to make sure that all the frost is gone. Thermostat evaporator returns the system to normal operation. "Pumping" is the control system. Thermostat works solenoid in the liquid line. At the same time, low-pressure switch compressor is running. To prevent the flow of liquid refrigerant from the evaporator to the compressor. This is especially important in cases of electric defrost.
When the thermostat is satisfied, he opens and liquid line solenoid is closed. The compressor continues to work and remove refrigerant vapour at the outlet of the evaporator and the suction line.
When properly low pressure is reached, the low pressure switch opens and stops the compressor. There should be Very little refrigerant in the compressor oil. When the pumping system is used for each cycle, crankcase heaters may be needed to drive the refrigerant cycle.
"Pump out" systems have additional relay is wired into the compressor circuit in parallel to the normal relay. It is connected to the thermostat circuit. Additional relay operates the start button on the normal starting relay. Compressor, therefore, may not resume until the thermostat points close.
In another electrical defrosting system, electric immersion heater heats a charge of refrigerant. Warm circulates the refrigerant in the evaporator when the unit is turned off, freezing the system. Another way of using electric heater freezing the system of double-tube evaporator. In the evaporator, the refrigerant passes through the passage between the pipes in the process of cooling. Electric heating elements inserted in the center of the tube, the defrosting system stops and electric heating elements are included. Thus, the reason tube evaporator defrost from the inside.
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