Evaporator Defrost cycle

When three-position selector switch is enabled defrost, solenoid and pilot solenoid valve D close as hot gas valve C and evaporator-pilot valve B open. This allows the hot gas to enter the evaporator. Valve D currently serves as a back-pressure regulator, pressure keeping above freezing point. After an adjustable delay, preferably closer to the end of defrost cycle, the time delay relay allows water solenoid open. This results in a spray of water through evaporation, melting ice, may be filed between the coils and brainwashing pan.

If the evaporator is defrosted, the system returns to the cooling cycle is turning a three-position switch. Hot gas solenoid (valve C) and integrated pilot valve (E) close as the liquid solenoid (valve) opens.

This system can be fully automatic replacement of manual switch with electric time. Table 10-2 lists some of the valve sizing for the low-temperature system.

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