Service Manual

11
II. Sequence of Operation and Service Diagnosis
A. Sequence of Operation Flow Charts
1. Refrigerator
3. Cool Down Restart
1. Startup/Cool Down
2. Cool Down Achieved
CTh in control
Slight Delay at Startup
CTh cools to 3°F (1.7°C) below setpoint. Factory default 38°F (3°C)
CTh warms to 3°F (1.7°C) above setpoint
4. Defrost
5. Defrost Termination
Note:
a) EvapFM delays energizing if DTh above 50°F (10°C). b) EvapFM de-energizes when door is opened on -FS models and when upper door is opened on -HS models. c) 2-min. minimum Comp on timer starts when Comp energizes. d) 2-min. minimum Comp off timer starts when Comp de-energizes. e) 5-min. minimum defrost time. f) 1-hr. maximum defrost time. g) "dEF" displayed during defrost. h) 15-minute temperature delay timer starts when Comp/ConFM energize. i) MH and BH de-energizes when Comp and CondFM de-energize on PT2A, RN2A, and RT2A models.
Power on
2-min. Comp off timer starts
2-min. Comp on timer starts
2-hr cumulative compressor run or 2-hr continuous compressor run defrost timer terminates
Legend: BH-bottom heater Comp-compressor ConFM-condenser fan motor CTh-cabinet thermistor DTh-defrost thermistor EvapFM-evaporator fan motor MH-mullion heater TXVH-thermostatic expansion valve heater
5-min. minimum defrost
DTh in control
DTh warms to 44°F (6.6°C) or 1-hr maximum defrost timer terminates
Comp energized ConFM energized EvapFM energized MH/BH energized (PT2A, R_2A)
Comp de-energized ConFM de-energized MH de-energized (PT2A, R_2A) EvapFM de-energized (60-sec. delay before de-energized)
EvapFM energized Comp de-energized ConFM de-energized MH/BH de-energized (PT2A, R_2A)
Comp energized ConFM energized EvapFM energized MH/BH energized (PT2A, R_2A)
Cycle Steps
Refrigerator Sequence Flow Chart
MH energized TXVH energized (R2A Models)
2-hr cumulative compressor run or 2-hr continuous compressor run defrost timer starts