How many minutes do you need to set the defrost timer?
In most cases you will set this to a maximum of 20 minutes. This timer consists of six terminals, a motor to run the clock, and a defrost termination solenoid (Figure 1). With the most common timer, there will be a copper jumper between terminals 1 and 2.
What kind of control is needed for low temp defrost?
LOW-TEMP DEFROST. It is necessary that another control be supplied at the evaporator that is wired to the X terminal to facilitate defrost termination. This thermostat is known as the “defrost termination-fan delay stat,” which is an SPDT (single-pole double-throw) thermostat. When the defrost solenoid is energized,…
When do you turn off the defrost on a refrigerator?
In off-cycle defrost, the defrosting of the evaporator is performed whenever the cold control (thermostat or low pressure control) is satisfied and the compressor is turned off. The evaporator fans continue to operate, blowing air through the evaporator quickly, causing the evaporator to warm up to the product temperature.
What should the temperature be for a refrigeration system to defrost?
The evaporator fans continue to operate, blowing air through the evaporator quickly, causing the evaporator to warm up to the product temperature. Because most short-term product storage will be maintained at between 33° and 38°, this temperature is sufficient to completely defrost most systems.
What happens at the end of the defrost cycle?
The defrost sequence is as follows: (1) Timer starts defrost cycle. (2) Liquid line solenoid valve closes, evaporator fans stop, and the defrost heaters are energized. (3) After pumping down, the compressor stops. (4) The heaters warm the coil, melt the frost, and trip the termination thermostat at the set temperature.
What’s the correct temperature for a defrost thermostat?
The defrost thermostat should be in the closed position when cold. Check to be sure the thermostat is opening at the correct temperature by placing it in water and slowly heating the water. Defrost thermostats are designed to open between 40 degrees and 90 degrees Fahrenheit.
How often does an evaporator coil need to be defrosted?
After a run period of approximately 6 hours, the evaporator coil will be frosted and require a defrost. Four defrost cycles per day are programmed at the factory (4 a.m., 10 a.m., 4 p.m., and 10 p.m.). It may be necessary to change the defrost cycle times to fit your work schedule.
What to do when your defroster stops working?
Solution: When the engine and radiator are cool, top up the coolant. Then warm up your vehicle and see if the defroster starts working better. If the coolant level is low due to a leak, have a mechanic find it and fix it. Without enough coolant, your engine will eventually overheat, leading to a much more expensive repair.