York Millennium YCAJ150, Installation Operation & Maintenance, Page: 19 / 116

FORM 150.65-NM4
19 YORK INTERNATIONAL
CHILLED LIQUID PIPING
GENERAL – When the unit has been located in its final
position, the unit liquid piping may be connected. Nor-
mal installation precautions should be observed in order
to receive maximum operating efficiencies. Piping 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 capacity,
all piping should be kept as simple as possible.
Hand stop valves should be installed in all lines to facili-
tate servicing.
Piping to the inlet and outlet connections of the chiller
should 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 sys-
tem.
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 pages 10 and 11.
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 wa-
ter lines. One connection point (plugged) is provided
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 climates.
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 chilier. 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 concern. How-
ever, if it is undesirable, it is the responsibility of the in-
staller to make provisions to field insulate the compressor
or install a factory insulation kit when they become avail-
able. Contact YORK Factory Marketing for availability.
ELECTRICAL WIRING
Liquid Chillers are shipped with all factory mounted con-
trols 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 circuit
ampacity and maximum dual element fuse size are given
on pages 12 - 15. A 115-1-60/50, 20 amp source must
be supplied for the control panel through a fused discon-
nect when a control panel transformer (optional) is not
provided. Refer to WIRING DIAGRAM page 20.
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 page 20.
MULTIPLE UNITS
For increased compressor protection and to reduce power
inrush at start-up on multiple chiller installations, provi-
sions must be made to prevent simultaneous startup 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.
RELIEF VALVES
An internal relief valve(s) is installed internally in each
compressor. A second integral internal relief valve is
built into the liquid line solenoid valve of each system.
All relief valves are resealable type safety devices.