Bypass and monitoring circuit for refrigeration system

摘要

Described herein is a refrigeration defrost cycle monitoring and bypass circuit which monitors the condition of the defrost terminator switch. More specifically, the circuit monitors whether the defrost terminator switch is stuck in either the open or the closed position. This is accomplished using timers to determine the period of time of the defrost cycle and the period of time the terminator switch is open. If either of these times exceed preset values, the defrost terminator switch function is eliminated from the circuit and the control it normally performs is substituted by predetermined times. This occurs by providing a resettable ground to the defrost relay so that it can sense the need to defrost and initiate a defrost cycle. After a defrost cycle is initiated, a user selectable timer ends the defrost cycle after the selected time.