Continental Refrigeration 4-840

HEATER DEFROST COIL (250W 20 1/2X3 1/4)

Various coils are used in restaurant equipment componentry. An electromagnetic coil is an electrical conductor such as a wire in the shape of a coil, spiral or helix. They are used in electrical engineering, in applications where electric currents interact with magnetic fields, in devices such as electric motors, generators, inductors, electromagnets, transformers, solenoid valves, and sensor coils. Either an electric current is passed through the wire of the coil to generate a magnetic field, or conversely an external time-varying magnetic field through the interior of the coil generates an EMF (voltage) in the conductor.

In refrigeration equipment, the "condenser coil" dispels hot air to the outside of the space. The refrigerant then loops back to the compressor, gets cold again, absorbs heat and disperses it to the outside. As long as the compressor is running, the refrigerant keeps up this continuous loop. Extracting heat from the storage space and transferring it to the refrigerant is the function of the "evaporator coil".

In dish washing machines, the steam coil preheats incoming water, reducing the energy needed to heat the water used in the sanitizing rinse.

The defrost mechanism in a refrigerator heats the cooling element (evaporator coil) for a short period of time and melts the frost that has formed on it. The resulting water drains through a duct at the back of the unit. Defrosting is controlled by an electric or electronic timer: For every 6, 8, 10, 12 or 24 hours of compressor operation it turns on a defrost heater for 15 minutes to half an hour.

A defrost thermostat opens the heater circuit when the evaporator temperature rises above a preset temperature, 40°F (5°C) or more, thereby preventing excessive heating of the freezer compartment. The defrost timer is such that either the compressor or the defrost heater is on, but not both at the same time.

A heating element converts electrical energy into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element. This process is independent of the direction of current.