Defrost Time Clock Wiring Diagram

A defrost time clock is an essential tool used in refrigeration systems to ensure that the evaporator coil is not frozen. It works by turning off the compressor and turning on the defrost heater at regular intervals to melt the ice on the coil. To understand how to install or repair a defrost time clock, you need to have a good understanding of its wiring diagram. This article will provide you with a comprehensive guide on how to wire a defrost time clock.

What is a Defrost Time Clock?

A defrost time clock is a device that controls the defrost cycle of a refrigeration system. It is designed to turn off the compressor at regular intervals and turn on the defrost heater to melt the ice on the evaporator coil. The defrost time clock is typically set to operate every 6, 8, 10, or 12 hours, depending on the refrigeration system’s needs.

The defrost time clock is an essential component of refrigeration systems that use electric defrost heaters. It helps to minimize the energy consumption of the system while also maintaining the ideal temperature of the refrigeration unit.

Defrost Time Clock Wiring Diagram

The wiring diagram of a defrost time clock consists of three main components: the timer motor, the defrost termination switch, and the defrost heater. These components are wired together to ensure that the defrost cycle is activated at the appropriate time.

The timer motor is responsible for turning the dial on the defrost time clock. It is powered by the same source that powers the compressor. The timer motor is typically wired to a set of contacts that control the defrost termination switch and the defrost heater.

The defrost termination switch is wired in series with the defrost heater. It acts as a safety device that ensures that the defrost cycle ends when the evaporator coil is completely defrosted. The defrost termination switch is typically located on the evaporator coil and is wired to the timer motor contacts.

The defrost heater is wired in parallel with the defrost termination switch. It is responsible for melting the ice that builds up on the evaporator coil during the cooling cycle. The defrost heater is typically located on the evaporator coil, and its wiring is also connected to the timer motor contacts.

Timer Motor Wiring

The timer motor is connected to the line voltage that powers the compressor. It is typically wired to a set of contacts that control the defrost termination switch and the defrost heater. The wiring diagram for the timer motor is as follows:

Wire Color Description Terminal
Black Line Voltage L1
White Neutral L2
Red Contacts (1) NO
Orange Contacts (2) NC

The black wire is connected to the line voltage that powers the compressor. The white wire is connected to the neutral wire. The red wire is connected to the normally open (NO) contact of the defrost termination switch. The orange wire is connected to the normally closed (NC) contact of the defrost termination switch.

Defrost Termination Switch Wiring

The defrost termination switch is connected in series with the defrost heater. It acts as a safety device that ensures that the defrost cycle ends when the evaporator coil is completely defrosted. The wiring diagram for the defrost termination switch is as follows:

Wire Color Description Terminal
Red Contacts (1) NO
Orange Contacts (2) NC
Blue Defrost Heater (1) NO
Yellow Defrost Heater (2) NC

The red wire is connected to the normally open (NO) contact of the defrost termination switch. The orange wire is connected to the normally closed (NC) contact of the defrost termination switch. The blue wire is connected to one of the terminals of the defrost heater, while the yellow wire is connected to the other terminal of the defrost heater.

Defrost Heater Wiring

The defrost heater is connected in parallel with the defrost termination switch. It is responsible for melting the ice that builds up on the evaporator coil during the cooling cycle. The wiring diagram for the defrost heater is as follows:

Wire Color Description Terminal
Blue Defrost Termination Switch (1) NO
Yellow Defrost Termination Switch (2) NC
Black Line Voltage L1
Red Defrost Termination Switch (1) NC

The blue wire is connected to the normally open (NO) contact of the defrost termination switch. The yellow wire is connected to the normally closed (NC) contact of the defrost termination switch. The black wire is connected to the line voltage that powers the compressor, while the red wire is connected to the normally closed (NC) contact of the defrost termination switch.

FAQs

What is the purpose of a defrost time clock?

A defrost time clock is designed to ensure that the evaporator coil in a refrigeration system is not frozen. It works by turning off the compressor and turning on the defrost heater at regular intervals to melt the ice on the coil.

How often should a defrost time clock operate?

The defrost time clock is typically set to operate every 6, 8, 10, or 12 hours, depending on the refrigeration system’s needs.

What is the defrost termination switch?

The defrost termination switch is a safety device that ensures that the defrost cycle ends when the evaporator coil is completely defrosted. It is wired in series with the defrost heater.

Where is the defrost termination switch located?

The defrost termination switch is typically located on the evaporator coil in a refrigeration system.

What is the defrost heater?

The defrost heater is a component of a refrigeration system that is responsible for melting the ice that builds up on the evaporator coil during the cooling cycle.

Conclusion

In conclusion, the wiring diagram of a defrost time clock consists of three main components: the timer motor, the defrost termination switch, and the defrost heater. These components are wired together to ensure that the defrost cycle is activated at the appropriate time, preventing the evaporator coil’s freezing. By following the wiring diagram, you can easily install or repair a defrost time clock in a refrigeration system.