JOHNSON CONTROLS
11
SECTION 1 - FIELD CONTROL MODIFICATIONS
FORM 161.01-PW2
ISSUE DATE: 7/18/2018
1
THERMAL TYPE FLOW SENSOR
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 solid state relay
output is turned on conducting current through the mi-
croboard load resistor to the +5VDC applying greater
than +4VDC to the microboard input J14-7.
When no flow of liquid is sensed, the solid state relay
output is turned off which results in less than 1VDC
to the microboard input and the OptiView™ Control
Center will display the following messages:
• CYCLING SHUTDOWN – AUTO RESTART
• CONDENSER FLOW SWITCH OPEN.
PADDLE TYPE FLOW SENSOR
If desired, a Condenser Liquid Flow Interlock can be
applied. The following two flow switches are avail-
able, at an additional cost:
• McDonnel type F61MG-1c, max. 150 psi (YORK
Part No. 024-26116)
• McDonnel type FS7-4W, max. 300 psi (YORK
Part No. 024-12144)
If Paddle-type (Digital) is selected and no condens-
er flow sensor is used, a jumper must be installed
between TB2-1 and TB2-11.
LD23515
Condenser
Flow Switch
Condenser
Flow Switch
Thermal-type Flow Sensor
TB2
Paddle-type Flow Sensor
To 24 VAC Supply
11
1
8
7
4
2
J14-
1
3
I/O
Board
Microboard
FIGURE 12 - CONDENSER FLOW SWITCHES
CONDENSER LIQUID PUMP RUN (TB5-150/151)
Contacts close coincident with “MBC Startup” and
open in coincidence with the receipt of a chiller STOP
command or any fault other than CONDENSER-
FLOW SWITCH OPEN cycling shutdown.
Contacts also close when Saturated Condenser Tem-
perature is less than 35.0 °F (1.7 °C) . This helps miti-
gate condenser freeze due to plant issues in brine ap-
plications. If the contacts are closed only due to the
Saturated Condenser Temp, they are opened when
Saturated Condenser Temperature returns above 40°F
(4.4 °C).
If it is desired to supply the dry contacts with 115VAC
power from the OptiView™ Control Panel to control
the Condenser Pump Motor Starter, a field installed
wire must be connected from TB9-22 to I/O Board
TB5-150. Then connect I/O Board TB5-151 to the
Condenser Pump Motor Starter.
FIGURE 11 - CONDENSER LIQUID PUMP RUN
LD23514
TB5
DO
150
151
I/O
Board
CONDENSER LIQUID FLOW SENSORS
The Thermal-type Flow Sensor interfaces with the
Microboard and Paddle-type Flow Sensor 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 entered at the keypad OPERATIONS Screen
using Service Access Level. Enter “J14” for Thermal-
type or “TB” for Paddle-type. Refer to YZ Operations
and Maintenance (Form 161.01-OM1).
When flow is sensed, the flow sensor contacts are
closed. Opening of the flow sensor contacts (no flow)
for 30 continuous seconds causes a cycling shutdown
displaying CONDENSER - FLOW SWITCH OPEN.
The flow sensor status is bypassed for the first 30 sec-
onds of “System Run”.
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