Johnson Controls 40 25 TON, Installation Operation & Maintenance

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JOHNSON CONTROLS
5276178-JIM-C-0118
5
the
“OCC ZONE COOLING SETPOINT”
plus 5°F
the Unit Controller will enter the COMFORT VENT
COOLING mode and initiate compressor operation.
If the
“SUPPLY AIR TEMP”
is equal to or less than
the
“OCC ZONE HEATING SETPOINT”
minus 5°F,
the Unit Controller will enter the COMFORT VENT
HEATING mode and initiate heating operation.
The Unit Controller will terminate COMFORT VENT
mode if:
•
The
“SUPPLY AIR TEMP”
is less than the
“OCC
ZONE COOLING SETPOINT” minus 5°F for 5
minutes.
•
The “SUPPLY AIR TEMP” is greater than the
“OCC ZONE HEATING SETPOINT” plus 5°F
for 5 minutes.
•
The unit switches into the OCCUPIED HEAT-
ING OR OCCUPIED COOLING mode as a result
of a space sensor demand for cooling or heating.
SYSTEM PUMP DOWN CONTROL
This feature is not available on this product.
HIGH DISCHARGE PRESSURE UNLOADING
This feature is not available on this product.
LOW AMBIENT LOCK OUT
The Unit Controller will allow compressor operation
down to 0.0°F for each refrigerant system that has a
discharge pressure transducer and a condenser fan VFD
installed. If the refrigerant system does not have both a
discharge pressure transducer and a condenser fan VFD,
the minimum outdoor temperature is 50.0°F. However
the decision can be made to prevent compressor
operation above this minimum allowable setting; 0.0°F
when discharge pressure transducers and condenser fan
VFD’s are installed or 50.0°F when discharge pressure
transducers and condenser fan VFD’s are not installed.
For low ambient operation the Lock Out Temperature
( “MECH CLG LOCKOUT TEMP” ) value is
programmed under the SETPOINT key, COOLING
subsection of the User Interface. THE “MECH COOL
LOCKOUT TEMP” can never be set lower than 0.0°F.
The addition of a condenser fan VFD is programmed
through “LOW AMBIENT PKG” which is under the
OPTION key, COMP SYSTEM 01 or 02 subsection
of the User Interface. The addition of discharge
pressure transducers is programmed through “PRESS
TRANS PKG” which is under the OPTION key, COMP
SYSTEM 01 or 02 subsection of the User Interface.
Both
“PRESS TRANS PKG”
and a
“LOW AMBIENT
PKG” can be programmed for NONE or SYS 1.
The Unit Control will derive an “ACTIVE MECH
COOL LOCKOUT TEMP”
value based on the following
criteria:
•
If the Discharge Pressure Transducer is unreliable
the “ACTIVE MECH COOL LOCKOUT TEMP” is
the higher of the “MECH CLG LOCKOUT TEMP”
or 50.0°F.
•
If the Outdoor Temperature sensor is unreliable all
compressor operation is prohibited.
•
If the Discharge Pressure Transducer and the Out-
door Temperature sensor are reliable the “ACTIVE
MECH COOL LOCKOUT TEMP”
will be the
higher of the “MECH CLG LOCKOUT TEMP” or
0.0°F.
•
If a “PRESSURE TRANS PKG” or “LOW AMBI-
ENT PKG” is not installed and the Outdoor Tem-
perature sensor is reliable the “ACTIVE MECH
COOL LOCKOUT TEMP”
will be the higher of
the
“MECH CLG LOCKOUT TEMP”
or 50.0°F.
If the Outside Air Temperature is less than or equal
to the “ACTIVE MECH COOL LOCKOUT TEMP”
for 10 seconds the Unit Control will turn off all the
compressors for the system.
If the Outside Air Temperature is greater than or equal
to the “ACTIVE MECH COOL LOCKOUT TEMP” plus
2.0°F for 10 seconds and the compressor minimum off
time has been satisfied the compressors will be allow
to restart.
During the time the Low Ambient Lock Out is active the
STATUS display of the User Interface will show
“LOW
AMB INHIBIT”
under the COMP SYS (1 or 2) STATUS
subsection. The SYSTEM STATUS subsection of the
COMPRESSOR SYSTEM (1 or 2) key will also show
“LOW AMB INHIBIT”.
LOW AMBIENT FAN CONTROL OPTION
If the refrigerant system is configured for low ambient