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FIG. 16 – AUXILIARY SAFETY SHUTDOWN INPUT
AUXILIARY SAFETY SHUTDOWN - The closure of a
Momentary or Maintained N.O. Switch or Relay Contacts
will cause the unit to shutdown and display: "SAFETY
SHUTDOWN - MANUAL RESTART" and "AUXILIARY
SAFETY - CONTACTS CLOSED". The unit may NOT be
restarted until the contacts open and the keypad COMPRES-
SOR switch is moved to the "STOP-RESET" position ( O )
and then to the "START" ( ◄ ) position.
I/O BOARD
PADDLE-TYPE FLOW SENSOR
OR DIFERENTIAL PRESSURE SWITCH
12
1
TB4
MICROBOARD
THERMAL-TYPE FLOW SENSOR
J7-
FIG. 17 – EVAPORATOR FLOW SENSORS
EVAPORATOR FLOW SENSORS - The chiller is sup-
plied with a thermal conductivity type flow sensor factory
installed in the evaporator liquid outlet nozzle.
The Thermal-type flow sensor interfaces with the Microboard.
The Paddle-type flow sensor of Differential Pressure Switch
interfaces with the I/O board.
For the program to read the appropriate inputs for the flow
sensor status, the actual flow sensor type used must be en-
12
LD04399
EVAPORATOR
LIQUID
LD13187
tered at the keypad using the Service Access Level. Enter
"Analog" for Thermal-type or "Digital" for Paddle-type or
Differential Pressure Switch. Refer to the Operation Manual
160.67 O1.
With any type of Flow Switch Sensor, when the Evaporator
Liquid is flowing, the flow switch contacts will close. If
the flow switch opens for 5 seconds, the unit shuts down
and displays " CYCLING SHUTDOWN" and "LEAVING
CHILLED LIQUID - FLOW SWITCH OPEN". The chiller
may be restarted when the switch again closes. The flow
switch status is checked 10 seconds (programmable up to
60 seconds) after the turbine slow roll has been completed
and the chilled liquid pump contacts have been closed, and
continuously thereafter.
THERMAL-TYPE FLOW SENSORS - When the
Thermal-type flow switch is used, the flow switch uses the
cooling effect of liquid to sense flow.
When the flow of liquid is sensed, the relay output is turned
ON conducting current through the microboard load resistor
to the +5VDC applying >+4VDC to the microboard input
J7-14.
When NO flow of liquid is sensed, the relay output is turned
OFF, this results in <1VDC to the microboard input and a
unit shutdown after a 5 second delay.
FIG. 17A – PADDLE-TYPE FLOW SENSOR
PADDLE-TYPE FLOW SENSOR - If desired, a paddle-
type flow sensor can be applied. Flow Switch - Johnson
Controls type F61MG-1C, max. 150 psi (YORK P/N 024-
26116-000) is available at an additional cost.
FORM 160.67-PW2 (1007)
LD04400
JOHNSON CONTROLS
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