Service Manual

11
II. Sequence of Operation and Service Diagnosis
The steps in the sequence are as outlined below.
A. Sequence of Operation Flow Chart
1. UR/WR: Refrigerator
Legend: Comp-compressor ConFM-condenser fan motor CTh-cabinet thermistor DLT-defrost lockout timer DT-defrost timer (cumulative) DTh-defrost thermistor EvapFM-evaporator fan motor
Note:
a) 2-min. minimum Comp on timer starts when Comp energizes b) 2-min. minimum Comp off timer starts when Comp de-energizes c) 5-hr. cumulative compressor run-time defrost timer d) 5-min. minimum defrost time e) 55-min. maximum defrost time f) 1-hr. minimum between defrost cycles (DLT)
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1. Startup/Cool Down
Comp energized ConFM energized EvapFM energized
5-hr. DT starts
Comp de-energized ConFM de-energized EvapFM de-energized
UR/WR - Refrigerator Sequence Flow Chart
2. Cool Down Achieved
4. Defrost
CTh above setpoint
CTh cools to setpoint
CTh above
setpoint
Defrost Termination: 45°F (7.2°C) achieved or 55 min. maximum DT terminated.
CTh in control
1-hr. DLT terminates
Evap. temp. at or below -4°F (-20°C) or 5-hr DT terminates 5-min. min. DT starts 55-min. max. DT starts Comp de-energized ConFM de-energized EvapFM energized
Defrost: Temperature or Time achieved. DTh achieves -4°F(-20°C) or 5-hr. DT terminates
Power on Yellow LED On (10-sec. Delay)
Evap. Temp. achieves 45°F (7.2°C) or 55-min. DT terminates, Defrost Terminated 1-hr. DLT starts 5-hr. DT starts Comp energized ConFM energized EvapFM energized
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DTh in control
5. Defrost Termination
3. Cool Down Restarts
5-min. minimum and
55-min. maximum
DT starts
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Red, Yellow, and Green LEDs Cycle
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Red and Green LEDs on Yellow LED off
Green LED on Red and Yellow LEDs off
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