Sequence Flow Charts; A) Refrigerator - Hoshizaki Commercial Series Service Manual

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1. Startup/Cool Down
Slight
Delay at
Startup
Power on
EvapFM energized
MH energized
PH energized
Refrigerator Sequence Flow Chart
2. Cool Down Achieved
3. Cool Down Restart
CTh cools
to 3°F (1.7°C)
below setpoint.
Factory default
36°F (2°C)
CTh in control
2-min. Comp off
2-min. Comp on
timer starts
timer starts
Comp energized EvapFM energized
ConFM energized MH energized
EvapFM energized PH energized
MH energized Comp de-energized
PH energized ConFM de-energized
Note:
Legend:
a) EvapFM de-energizes when door is opened on FS and when
Comp-compressor
ConFM-condenser fan motor
b) 2-minute minimum Comp on timer starts when Comp energizes.
CTh-cabinet thermistor
c) 2-minute minimum Comp off timer starts when Comp de-energizes.
DTh-defrost thermistor
d) 2-minute temperature display delay timer starts when defrost
EvapFM-evaporator fan motor
MH-mullion heater
e) 20-minute minimum defrost time.
PH-perimeter heater
f) 1-hour maximum defrost time.
4. Defrost
CTh warms DTh cools to
to 3°F (1.7°C) 8.6°F (-13°C)
above
setpoint
DTh in control
EvapFM energized
MH energized
PH energized
Comp de-energized
ConFM de-energized
upper door is opened on HS.
termination temperature is met.
5. Defrost Termination
DTh warms to
40°F (4.4°C)
-min. temperature display
2
delay timer starts
Comp energized
ConFM energized
EvapFM energized
MH energized
PH energized