Johnson Controls YEWS Series, Installation, Operation And Maintanance Instructions

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D =1.447 x L
Where:
D =minimum pipe internal diameter in centimeters (cm)
L =length of pipe in meters (m)
If relief pipework is common to more than one valve, its
cross sectional area must be at least the total required by
each valve. Valve types should not be mixed on a common
pipe. Precautions should be taken to ensure that the exit of
relief valves/vent pipe remain clear of obstructions at all
times.
4.9 Electrical Connection
YEWS product is suitable for 60Hz application, but the
compressor can only be applied to 460V/60Hz, when the
field power supply is 230V/60Hz, the transformer is
necessary to make the chiller operation (the transformer
will be shipped along with the chiller). And YEWS
product control panel can only provide 220VAC power,
please check if the equipment connected to the control
panel is suitable for 220VAC voltage.
Please refer electrical drawingsfor 60Hz powerto find the
details for field power connection.
The following connection recommendations are intended
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 York control panel should not be run through the
control panel. If these precautions are not followed it
could lead to a risk of electric shock. In addition,
electrical noise could cause malfunctions or damage the
unit and its controls.
Since some internal components are live when main
power is switched on, the unit should not be switched on
to the main power until it has been commissioned by York
authorized personnel after connection.
All customer wiring at the jobsite must be routed
to avoid high temperature areas (compressor
shells, discharge piping, ambient coils and other
hot surfaces) and sharp edges on the unit, to
prevent damage to the wiring and possible short
circuits. If these precautions are not followed it
could lead to a risk of electrocution or damage to
Cooling tower
Pump
Bypass of condenser
Tee valve
Bypass
Cooling tower
or other cooli-
ng source
Cycling loop
Tee valve
Condenser
Pump
Direct Pressure Control
With YEWS-E units it is possible, if desired, to control the
condenser cooling liquid inlet temperature/flow directly
from the unit refrigerant pressure. The refrigerant pressure
can either be used to control cooling tower effectiveness by
controlling fans or dampers on the tower, or to control
condenser water flow using a three way bypass valve.The
purpose of this method is to keep a low and steady
discharge pressure .But with the units using R134
YEWS-E Water Cooling Screw Chiller/Heat Pump
16
the unit and its controls.
4.10 Condenser Cooling Water System
For YEWS-E units, condensers are usually piped in
conjunction with a cooling tower.
With water cooled units it is necessary to control the
condenser water flow and/or temperature into the condenser
to maintain refrigerant pressure as constant as possible to
ensure satisfactory operation of the unit.
WARNING