Section 2 - Energy Management Systems - York YZ Wiring Diagrams

FORM 161.01-PW2
ISSUE DATE: 7/18/2018

SECTION 2 - ENERGY MANAGEMENT SYSTEMS

YZ chiller design allows with an ease to interface
with the Energy Management Systems (EMS). The
OptiView™ Control Center includes unit status con-
tacts, provisions for remote control inputs and provi-
sions for remote setpoint reset of leaving chilled liquid
temperature and current limit for EMS interfacing (see
Note 7 on page 18).
Five sets of unit status contacts are factory furnished
through a field wiring terminal board in the Optiv-
iew™ Control Center. Each set of contacts are by de-
fault open, single pole, rated at 5 AMPS resistive at
240VAC. The following Chiller status contacts are pro-
vided for the unit:
• Remote Mode Ready to Start – See Figure 1 on
page 8
• Cycling Shutdown Alarm – See Figure 2 on
page 8
• Safety Shutdown Alarm– See Figure 3 on page
8
• Run (System Operating) – See Figure 4 on page
9
• Warning Alarm – See Figure 5 on page 9
Three sets of inputs are available to the EMS, allow-
ing for remote control of unit operation. Input device
contact rating shall be 5 mA at 115VAC. Field wiring
terminal board in the OptiView™ Control Center per-
mits connection for the following operation:
• Remote Run/Stop Contacts TB3-7 and TB3-1 –
See Figure 6 on page 9
• Remote/Local Cycling TB2-13 and TB2-1 – See
Figure 8 on page 10
• Multi-unit Cycling Shutdown TB2-9 and
TB2-1 – See Figure 9 on page 10
Chiller cycling by the Energy Management System
should be minimized. It is possible to limit the com-
pressor motor amp draw indirectly or directly by the
following methods:
1. Application of Sequence Control Kit: only one
unit is running, when a single unit can carry the
cooling load.
JOHNSON CONTROLS
2. When multiple unit installations are controlled by
an EMS, remote Run/Stop con tacts are available
to start and stop each chiller, see Figure 6 on page
9. Contact rating shall be 5 milliamperes at
115VAC.
3. The OptiView™ Control Center has a program-
mable time clock function as a standard feature
with holiday capability. This offers one preset
automatic Start-Stop per day on a seven day cal-
endar basis with the ability to program a single
additional holiday start and stop time up to a week
in advance. Chilled water pump control contacts
(see Note 13 on page 7) are also provided,
allowing for efficient automatic operation of the
chilled water pump to reduce energy. Two chilled
water pump operating modes are available via the
CHW PUMP programming on the OptiView™
Setup Screen. With the Standard setting, the
chilled water pump operates for 30 seconds prior
to chiller start, during chiller operation, coast-
down, and LWT cycling shutdowns. With the
Enhanced setting, the chilled water pump operates
as above plus it operates during MULTI-UNIT
and REMOTE/LOCAL cycling shutdowns.
4. Reduce the compressor-motor kW input (and
thus amps) by raising the leaving chilled liquid
tempera ture through remote temperature control
setpoint. Remote tem perature reset is accom-
plished by supplying a 1 to 11 second pulse-width
modulated signal, refer to Figure 19 on page
15. With the through use of the remote tem-
perature control analog input on the microboard,
the leaving chilled liquid temperature may be re-
set via a 4 to 20mA D.C. current signal, or a 0 to
10VDC signal
5. Current limiting of demand during pulldown
may be accomplished by using the standard
PULLDOWN DEMAND LIMIT function pro-
vided in the OptiView™ Control Center. The
PULLDOWN DEMAND LIMIT key can be pro-
grammed to limit compressor motor current from
30 to 100 percent of full load AMPS, for 1 to 255
minutes following each compressor start. It is only
active when the Current Limit Control Source is
set to Local. For more details refer to YZ Opera-
tions and Maintenance (Form 161.01-OM1).
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