JOHNSON CONTROLS
14
FORM 160.84-OM1
ISSUE DATE: 9/21/2017
SECTION 1 - SYSTEM FUNDAMENTALS
The control center continually monitors the system op-
eration and records the cause of any shutdowns (Safe-
ty, Cycling or Normal). This information is recorded in
memory and is preserved even through a power failure
condition. The user may recall it for viewing at any
time. During operation, the user is continually advised
of the operating conditions by various status and warn-
ing messages. In addition, it may be configured to noti-
fy the user of certain conditions via alarms. A complete
listing of shutdown, status, and warning messages is
attached in the Display Messages on page 88 of this
manual.
The control center includes capabilities for remote con-
trol and communications. Common networking proto-
col through the Building Automation System (BAS) al-
lows increased remote control of the chiller, as well as
24-hour performance monitoring via a remote site. An
optional circuit board called the SC-EQUIP provides
Johnson Controls and YORK mechanical equipment
such as the YMC
2
chiller with building automation
system (BAS) networking connectivity.
The chiller also maintains the standard digital remote
capabilities as well. Both of these remote control capa-
bilities allow for the following standard Energy Man-
agement System (EMS) interfaces. The actual connec-
tion details are in the Field Connections section of the
Wiring Diagram (Form 160.84-PW1 and PW3):
• Remote Start
• Remote Stop
• Remote Leaving Chilled Liquid Temperature
Setpoint adjustment: BAS coms, Analog signal,
(0-10VDC, 2-10VDC, 0-20mA or 4-20mA) or
Pulse Width Modulation
• Remote Current Limit Setpoint adjustment: BAS
coms, Analog signal, (0-10VDC, 2-10VDC,
0-20mA or 4-20mA) or Pulse Width Modulation
• Remote “Ready to Start” Contacts
• Safety Shutdown Contacts
• Cycling Shutdown Contacts
The OptiView™ panel can be used to control the cus-
tomer chilled and condenser liquid flow. A set of con-
tacts exists to initiate flow for each shell. Details are in
the Field Connections section of the Wiring Diagram
(Form 160.84-PW2 and PW4). The chilled water pump
contacts close immediately upon execution of a chiller
start command. They open coincident with the receipt
of a stop command or a fault other than those below:
A. LEAVING CHILLED LIQUID - LOW TEM-
PERATURE cycling shutdown.
B. MULTIUNIT CYCLING - CONTACTS OPEN
or SYSTEM CYCLING - CONTACTS OPEN
(Only if Chilled Liquid Pump Operation is set to
ENHANCED)
C. LEAVING CHILLED LIQUID FLOW SWITCH
OPEN cycling shutdown
The Condenser Pump contacts close immediately upon
execution of a chiller start command. They open coin-
cident with receipt of a chiller stop command or fault
other than CONDENSER-FLOW SWITCH OPEN cy-
cling shutdown.
If the chiller is Stopped and the Condenser Pump con-
tacts are open (flow off), the contacts close when Satu-
rated Condenser Temperature is less than 35.0 °F. This
helps mitigate condenser freeze due to plant issues in
brine applications.
If the contacts are closed only due to the Saturated
Condenser Temp, they are opened when Saturated
Condenser Temperature returns above 40.0 °F. If the
existing logic calls for them to be closed, they remain
closed.
Some screens, displayed values, programmable
setpoints and manual controls exist for Service Techni-
cian use only. They are only displayed when logged in
at SERVICE access level or higher. The setpoints and
parameters displayed on these screens are explained in
detail in YORK YMC
2
Service Manual (Form 160.84-
M2). These parameters affect chiller operation and
should never be modified by anyone other than a quali-
fied Service Technician. The advanced diagnostics and
troubleshooting information for Service Technicians
are included in YORK YMC
2
Service Manual (Form
160.84-M2). Also included in the Service manual are
detailed descriptions of chiller features, such as Capac-
ity Control, Refrigerant Level Control, Variable geom-
etry diffuser, and Magnetic bearing controller.
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