Robertshaw Commercial Defrost 8047-20

The Robertshaw 8047-20 is a commercial defrost timer for 208/240 volt circuits, used to control defrost cycles in refrigeration systems.

Defrost control schemes differ in how the cycle is started and how it is ended, and understanding the distinction is central to diagnosing defrost faults.

Time initiated defrost begins the cycle at fixed intervals set on the timer. Time terminated defrost ends it after a fixed duration. A purely time initiated and time terminated arrangement is simple, but it is inherently a compromise: the interval must be short enough for the worst conditions and the duration long enough for the heaviest frost, which means most cycles are longer and more frequent than necessary.

Temperature termination improves on this. A termination thermostat on the coil ends the defrost as soon as the coil has cleared, with the timer providing only a fail-safe maximum duration. Cycles then take only as long as they need to.

Which arrangement a given timer supports determines how it is wired and what additional components the system requires.

Where defrost problems are reported, establishing which scheme the system uses is the necessary first step before adjusting anything.

Applications include commercial refrigeration, walk-in coolers and freezers, and display cases.

Brand

Robertshaw

SKU

8047-20

Category

Defrost Timers

Weight

2.95 lbs

Dimensions

7.80" x 4.40" x 3.00"

Price

$160.00

Availability

In stock

Rating

5 / 5.0