York MAXE YST, Wiring Diagram

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JOHNSON CONTROLS
6
FORM 160.67-PW2 (1007)
LD06825
FIG. 7 – REMOTE/LOCAL CYCLING DEVICES
(CONTROLLED SHUTDOWN)
REMOTE/LOCAL CYCLING DEVICES
(CONTROLLED SHUTDOWN)
The closure of an automatic reset device across this
input will permit the unit to operate in all operating
modes. Conversely, an opening of the device contacts
will inhibit the unit from operating; the OptiView
™
Con-
trol Center will then display the following massages:
"CYCLING SHUTDOWN - AUTO RESTART" and
"SYSTEM CYCLING - CONTACTS OPEN".
A "Controlled Shutdown" initiated by
the opening of these contacts while the
chiller is running causes the speed to
be reduced, the compressor pre-rota-
tion vanes to close, and the hot gas
bypass valve to open prior to tripping
the turbine. A subsequent closure
of these contacts will initiate a start
sequence.
CONDENSER FLOW SENSORS
The chiller is supplied with a thermal conductivity type
fl ow sensor factory installed in the condenser liquid
outlet nozzle.
The Thermal-Type fl ow sensor interfaces with the
microboard. The paddle type fl ow sensor or Differential
Pressure Switch interfaces with the I/O board.
For the program to read the appropriate inputs for the
fl ow sensor status, the actual fl ow sensor type used must
be entered at the keypad using Service Access Level.
Enter "Analog" for thermal-type or "Digital" for paddle-
type or differential pressure switch. Refer to Operation
manual 160.67-O1.
With any of the fl ow sensors, when condenser liquid
is fl owing, the Flow Switch contact will close. Open-
ing of the condenser liquid fl ow switch contacts for
30 continuous seconds will cause unit shutdown. The
Flow Switch Status is checked 45 seconds into "System
Prelube" and continuously thereafter. The OptiView
™
Control Center will display the following message:
"CYCLING SHUTDOWN - AUTO RESTART" and
"CONDENSER FLOW SWITCH OPEN".
THERMAL TYPE FLOW SENSOR
When the Thermal-type fl ow switch is used, the fl ow
switch uses the cooling effect of liquid to sense fl ow.
When the fl ow of liquid is sensed, the solid-state re-
lay output is turned ON conduction current through
the microboard load resistor to the +5Vdc Applying
>+4Vdc to the microboard input J7-16.
When no fl ow of liquid is sensed, the solid state re-
lay output is turned off, this results in <1Vdc to the
microboard input and a unit shutdown after a 30 second
delay.
J7-
MICROBOARD
THERMAL-TYPE FLOW SENSOR
11
1
TB4
LD9133
FIG. 8 – CONDENSER FLOW SENSORS
I/O BOARD PADDLE-TYPE FLOW SENSOR
OR DIFFERENTIAL PRESSURE SWITCH