York YCAZ33BA3, Manual, Page: 15 / 88

FORM 150.44-NM4
15
YORK INTERNATIONAL
CHILLED LIQUID PIPING
GENERAL – When the unit has been located in its fi-
nal position, the unit liquid piping may be connected.
Normal installation precautions should be observed in
order to receive maximum operating efficiencies. Pip-
ing should be kept free of all foreign matter. All liquid
cooler piping must comply in all respects with local
plumbing codes and ordinances.
Since elbows, tees and valves decrease pump capac-
ity, all piping should be kept as simple as possible.
Hand stop valve should be installed in all lines to facili-
tate servicing.
Piping to the inlet and outlet connections of the chiller
may include high-pressure rubber hose or piping loops
to insure against transmission of water pump vibration.
This is optional and the necessary components must
be obtained in the field.
Drain connections should be provided at all low points
to permit complete drainage of liquid cooler and piping
system.
A small valve or valves should be installed at the highest
point or points in the chilled liquid piping to allow any trapped
air to be purged. Vent and drain connections should be
extended beyond the insulation to make them accessible.
The piping to and from the cooler must be designed to
suit the individual installation. It is important that the
following considerations be observed:
1. The chilled liquid piping system should be laid out
so that the circulating pump discharges directly into
the cooler. The suction for this pump should be taken
from the piping system return line and not the cooler.
2. The inlet and outlet cooler liquid connection sizes
are given on page 9.
3. A strainer, preferably 40 mesh, MUST be installed
in the cooler inlet line just ahead of the cooler.
4. All chilled liquid piping should be thoroughly flushed
to free it from foreign material before the system is
placed into operation. Use care not to flush any for-
eign material into or through the cooler.
5. As an aid to servicing, thermometers and pressure
gauges should be installed in the inlet and outlet
water lines. One connection point (plugged) is pro-
vided in each cooler nozzle. Thermometers and
gauges are not furnished with the unit and are to be
furnished by other suppliers.
6. The chilled liquid lines that are exposed to outdoor
ambients should be wrapped with a supplemental
heater cable and insulated to protect against freeze-
up during low ambient periods, and to prevent forma-
tion of condensation on lines in warm humid cli-
mates.
7. A chilled water flow switch, (either by YORK or oth-
ers) MUST be installed in the leaving water piping
of the cooler. There should be a straight horizontal
run of at least 5 diameters on each side of the switch.
Adjust the flow switch paddle to the size of pipe in
which it is to be installed. (See manufacturer’s in-
structions furnished with switch). The switch is to
be wired to terminals in the control panel as shown
in the WIRING DIAGRAM.
WARNING: Flow switch must not be used to stop and
start chiller. It is intended only as a safety
switch.
COMPRESSOR INSULATION
In high humidity environments, compressor sweating
may be noted. In most applications, this is of no con-
cern. However, if it is undesirable, it is the responsibil-
ity of the installer to make provisions to field insulate
the compressor or install a factory insulation kit when
they become available. Contact your local YORK Sales
Office for availability.
ELECTRICAL WIRING
Liquid Chillers are shipped with all factory mounted
controls wired for operation.
Field Wiring – Power wiring must be provided through
a fused disconnect switch to the unit terminals (or op-
tional molded case disconnect switch) in accordance
with N.E.C. or local code requirements. Minimum cir-
cuit ampacity and maximum dual element fuse size are
given on pages 10 and 11. A 115-1-60/50, 20 amp
source must be supplied for the control panel through
a fused disconnect when a control panel transformer
(optional) is not provided. Refer to WIRING DIAGRAM.
Affiliated apparatus, such as a chilled water flow switch,
auxiliary contacts from the chilled water pump starter,
alarms, etc., should be interlocked into the control panel
circuit. These field modifications may be made as
shown on the WIRING DIAGRAM.
MULTIPLE UNITS
For increased compressor protection and to reduce
power inrush at start-up on multiple chiller installations,
provisions must be made to prevent simultaneous start-
up of two or more units. Also, some method must be
employed to automatically cycle one or more of the units
on or off to permit more efficient operation at part load
conditions. A sequencing kit may be acquired through
your local YORK representative.