York YCAS0098EB, Installation Operation & Maintenance, Page: 34 / 184

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JOHNSON CONTROLS
If the ducts from two or more fans are to be combined
into a common duct, back-flow dampers should be fitted
in the individual fan ducts. This will prevent recircula-
tion of air when only one of the fans is running.
Units are supplied with outlet guards for safety and to
prevent damage to the fan blades. If these guards are re-
moved to fit ductwork, adequate alternative precautions
must be taken to ensure persons cannot be harmed or
put at risk from rotating fan blades.
ELECTRICAL CONNECTION
The following connection recommendations are in-
tended to ensure safe and satisfactory operation of the
unit. Failure to follow these recommendations could
cause harm to persons, or damage to the unit, and may
invalidate the warranty.
No additional controls (relays, etc.)
should be mounted in the control
panel. Power and control wiring not
connected to the control panel should
not be run through the control panel.
If these precautions are not followed it
could lead to a risk of electrocution. In
addition, electrical noise could cause
malfunctions or damage the unit and
its controls.
After connection do not switch on
mains power to the unit. Some inter‑
nal components are live when mains
is switched on and this must only be
done by Authorized persons.
POWER WIRING
All electrical wiring should be carried out in accordance
with local regulations. Route properly sized cables to
cable entries on both sides of the unit.
In accordance with U.L. Standard it is the responsibil-
ity of the user to install overcurrent protection devices
between the supply conductors and the power supply
terminals on the unit.
To ensure that no eddy currents are set up in the power
panel, the cables forming each 3-phase power supply
must enter via the same cable entry.
All sources of supply to the unit must
be taken via a common point of isola‑
tion (not supplied by YORK).
STANDARD UNITS WITH MULTI POINT POWER
SUPPLY WIRING
Standard units require two 3-phase separately fused
3- wire supplies plus a ground per refrigerant system.
One supply to be connected to each of the power panels.
Connect each of the main 3-phase supplies to the circuit
breakers, non-fused disconnect switches or terminal
boards located in the power panels using lug sizes de-
tailed in the Technical Data Section.
Connect the ground wires to the main protective ground
terminals in each power panel.
Units with Single-Point Power Supply Wiring
Units require only one 3-phase plus ground.
Connect the 3-phase supplies to the terminal block or
non-fused disconnect switch located in the options panel
using lug sizes detailed in the Technical Data Section.
Connect a ground wire to the main protective ground
terminal.
115VAC CONTROL SUPPLY TRANSFORMER
A 3-wire high voltage to 115VAC supply transformer
is standard in the chiller. This transformer is mounted
in the Options Cabinet and steps down the high voltage
supply to 115VAC to be used by the Micro Panel, Power
Panel components, solenoids, heaters, etc.
The high voltage for the transformer primary is taken
from the chiller input to one of the systems. Fusing is
provided for the transformer.
It is important to check that the cor‑
rect primary tapping has been used
and that it conforms to the site high
voltage supply.
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