CSZ EZT-570i, Technical Manual

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EZT-570i Technical Manual
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System 1B Pumpdown Switch (I31):
This input is a control input for pumpdown (if equipped). There is
no user indication for this input. When refrigeration system
requires pumpdown, this input is wired to a low pressure switch
on the suction line of system 1B compressor. When the
pressure rises, the switch closes and turns on the input.
The EZT then turns on the system 1B compressor output (Q46)
until the input turns off. When the input turns off, indicating that
the compressor has pumped down, the EZT turns off the system
1B compressor output. During pumpdown, the system 1B
solenoids output (Q45) remains off in order to isolate the low
side of the refrigeration system so it can be pumped down.
Sys ‘A’ Oil Pressure Safety (I33):
The system ‘A’ oil pressure safety input is used to indicate that
the system 1A or system 2A compressor oil pressure is below
the proper operating range (if equipped). This input is active low,
i.e., the input must be off in order for the alarm to be indicated.
When active (input off), the EZT shuts down the chamber until
the alarm is acknowledged (silence button pressed on alarm
monitor screen) and the input is on (requires manual reset of oil
pressure safety).
Sys ‘A’ Protection Module (I34):
The system ‘A’ compressor protection module input is used to
indicate that the system 1A or system 2A compressor protection
module has detected an improper phase condition/loss or the
compressor motor windings have overheated (if equipped). This
input is active low, i.e., the input must be off in order for the
alarm to be indicated. When active (input off), the EZT shuts
down the chamber until the alarm is acknowledged (silence
button pressed on alarm monitor screen) and the input is on
(automatically resets after built-in timeout period).
Sys ‘B’ Discharge Thermostat (I35): The system ‘B’ discharge thermostat input is used to indicate
that the system 1B or system 2B compressor discharge
temperature has exceeded the maximum operating range (if
equipped). This input is active low, i.e., the input must be off in
order for the alarm to be indicated. When active (input off), the
EZT shuts down the chamber until the alarm is acknowledged
(silence button pressed on alarm monitor screen) and the input is
on (automatically resets after allowed to cool down).
Sys ‘B’ Oil Pressure Safety (I36):
The system ‘B’ oil pressure safety input is used to indicate that
the system 1B or system 2B compressor oil pressure is below
the proper operating range (if equipped). This input is active low,
i.e., the input must be off in order for the alarm to be indicated.
When active (input off), the EZT shuts down the chamber until
the alarm is acknowledged (silence button pressed on alarm
monitor screen) and the input is on (requires manual reset of oil
pressure safety).