34
JOHNSON CONTROLS
FORM 201.21-NM4 (616)
34
JOHNSON CONTROLS
INSTALLATION
After power wiring connection, do not
switch on mains power to the unit.
Some internal components are live
when the mains are switched on and
this must only be done by “Authorized”
persons familiar with starting, operat-
ing, and troubleshooting this type of
equipment
POWER WIRING
All electrical wiring should be carried out in accordance
with local regulations. Route properly sized cables to
cable entries on the unit.
In accordance with local codes, NEC codes and U.L.
Standards, it is the responsibility of the user to install
over current protection devices between the supply con-
ductors and the power supply terminals on the unit.
To ensure that no eddy currents are set up in the power
panel, the cables forming the 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 isolation
(not supplied by YORK).
Copper power wiring only should be used for supply-
ing power to the chiller. This is recommended to avoid
safety and reliability issues resulting from connection
failure at the power connections to the chiller. Alumi-
num wiring is not recommended due to thermal charac-
teristics that may cause loose terminations resulting from
the contraction and expansion of the wiring. Aluminum
oxide may also build up at the termination causing hot
spots and eventual failure. If aluminum wiring is used
to supply power to the chiller, AL-CU compression
fittings should be used to transition from aluminum to
copper. This transition should be done in an external
box separate to the power panel. Copper conductors
can then be run from the box to the chiller.
POWER SUPPLY WIRING
Units require only one 3-phase supply, plus earth
ground.
Connect the 3-phase supplies to the terminal block or
optional circuit breaker located in the panel using lug
sizes detailed in the Technical Data Section.
Connect a ground wire from the chiller panel ground
lug to the incoming line supply ground.
115VAC CONTROL SUPPLY TRANSFORMER
A 3-wire high voltage to 115VAC supply transformer is
standard in the chiller. This transformer is mounted in
the Cabinet and steps down the high voltage supply to
115VAC to be used by the Controls, VSD, Feed & Drain
Valve Controller, valves, solenoids, heaters, etc.
The high voltage for the transformer primary is taken
from the chiller input. Fusing is provided for the trans-
former.
Removing high voltage power to
the chiller will remove the 115VAC
supply voltage to the control panel
circuitry and the evaporator heater. In
cold weather, this could cause serious
damage to the chiller due to evaporator
freeze-up. Do not remove power unless
alternate means are taken to ensure
operation of the evaporator heater.
CONTROL PANEL WIRING
All control wiring utilizing contact closures to the con-
trol panel terminal block is nominal 115VAC and must
be run in shielded cable, with the shield grounded at
the panel end only, and run in water tight conduit. Run
shielded cable separately from mains cable to avoid
electrical noise pick-up. Use the control panel cable
entry to avoid the power cables.
Voltage free contacts connected to the panel must be
suitable for 115 VAC-10ma (gold contacts recommend-
ed). If the voltage free contacts form part of a relay or
contactor, the coil of the device must be suppressed using
a standard R/C suppressor. The above precautions must
be taken to avoid electrical noise, which could cause a
malfunction or damage to the unit and its controls.
