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removed from the compressor contactors shutting down
the compressor. Auto restart will not occur since manual
reset is required. A fault lockout will automatically occur
after the micro attempts 2 more starts with the MP con-
tacts open. Manual reset is accomplished by removing
115VAC control power from the micro panel after the
motor sensors have sufficient time to cool. Details re-
lating to operation of the Motor Protection Module can
be found on page 18.
The Mechanical High Pressure Cutout protects against
excessive refrigerant discharge pressure and is set to
405 PSIG (28 bar). Auto-restart will be permitted after
shutdown on discharge pressure, when the pressure
drops below 330 PSIG (23 bar) and the cutout contacts
close. A fault lockout will result if safety thresholds are
exceeded three times in a 90 minute period.
Low Evaporator Temperature Cutout (R407C Only):
S Y S
1
L O W
S Y S
2
L O W
The Low Evaporator Temperature Cutout is to pro-
tect the evaporator from freeze-up with R-407C. This
safety uses the Cooler Inlet Refrigerant Temp Sensors
to monitor evaporator inlet refrigerant temperature on
each system. These sensors are only installed on R-407C
units. If the refrigerant temperature falls below 21°F
JOHNSON CONTROLS
E V A P
T E M P
E V A P
T E M P
(-6°C) in water cooling mode, the system will be shut
down. If the refrigerant temp falls 19°F (11°C) below
the leaving chilled liquid temp in glycol cooling mode,
the system will shut down. Also, if the cooler inlet re-
frigerant temp sensor reads out of range low, the system
will also shut down.
2.7
PRINTOUT ON FAULT SHUTDOWN
If an optional printer is installed, the contents of His-
tory Buffer 1 will be sent to the printer any time a fault
shutdown occurs. This will allow record keeping of
individual faults, even if they do not cause a lockout of
the system. This information may be useful to identify
developing problems and troubleshooting.
The No Run Permissive fault messages will not be stored
in the History Buffer and will not cause an auto printout.
Due to extreme operating conditions or sys‑
tems where control deficiencies
are present, occasional faults may
occur with the corresponding auto‑
matic printout. This is not a cause for
concern.
FORM 201.18-NM7
8
141
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