23
field-supplied
1
/
4
-in. (6.4 mm) copper line
must
be run
from the
1
/
4
-in. NPT port on the back-pressure valve cap
to the
1
/
4
-in. SAE flare fitting on the motor cooling line.
The equalizer line must be installed in order for the unit to
function properly.
NOTE: A ball valve can be installed in the equalizer line
to facilitate servicing.
4. After mounting the back-pressure valve to the unit, prop-
erly supporting it, and running the
1
/
4
-in. equalizer line,
the discharge piping may be installed.
5. Repeat Steps 1-4 for the other refrigerant circuit.
The 30HXA206-271 machines have 2 back pressure valves
on circuit A. The equalizer line should connect to the
1
/
4
-in.
NPT ports on each valve then tee together and run to the
1
/
4
-in.
SAE flare tee provided in the circuit A economizer transducer
connection. The discharge piping from each valve should tee
together as close to the machine as possible. See Fig. 20.
Evacuation and Dehydration — Because the 30HXA systems
use polyolester oil, which can absorb moisture, it is important
to minimize the amount of time that the system interior is left
exposed to the atmosphere. Minimizing the exposure time of
the oil to the atmosphere will minimize the amount of moisture
that needs to be removed during evacuation.
Once all of the piping connections are complete, leak test
the unit and then pull a deep dehydration vacuum. Connect the
vacuum pump to the charging valve at the bottom of the cooler
and
to the liquid line service valve. For best results, it is recom-
mended that a vacuum of at least 500 microns (0.5 mm Hg) be
obtained. Afterwards, to ensure that no moisture is present in
the system, perform a standing vacuum-rise test.
With the unit in deep vacuum (500 microns or less), isolate
the vacuum pump from the system. Observe the rate-of-rise of
the vacuum in the system. If the vacuum rises by more than
50 microns in a 30-minute time period, then continue the
dehydration process. Maintain a vacuum on the system until
the standing vacuum requirement is met. This will ensure a dry
system.
By following these evacuation and dehydration procedures,
the amount of moisture present in the system will be
minimized. It is required that replaceable core liquid line filter
driers be installed between the condenser(s) and the expansion
devices to capture any foreign debris and provide additional
moisture removal capacity. Be sure to consider the pressure
drop of the filter drier when determining piping requirements.
The factory-supplied strainer may be removed to reduce
pressure drop provided the filter drier is located as close to the
unit as possible.
For further 30HXA piping instructions, proceed to the
section titled Install Pressure Relief Refrigerant Vent Piping.
30HXC PIPING AND VALVE INSTALLATION
30HXC Condenser Connections — The inlet fluid connec-
tion is always the lower of the 2 condenser connections. A
screen strainer with a minimum of 20 mesh must be installed
ahead of the condenser inlet (within 10 ft [3.05 m]) to prevent
debris from damaging the internal condenser tubes.
The outlet water connection is the upper connection of the
2 connections. The condenser has victaulic nozzles to connect
field-supplied piping. Plan the piping arrangement in accor-
dance with good piping practices and so that the piping does
not cross in front of the condenser head. Use flexible
connections on the condenser piping to reduce vibration trans-
mission. Offset the piping to permit condenser head removal
for maintenance purposes. Install pipe hangers where needed.
Make sure no weight or stress is placed on the water nozzle.
Provide openings in water piping for pressure gages and
thermometers (if used). These openings should be 5 to 10 pipe
diameters from the unit water nozzles. For thorough mixing
and temperature stabilization, wells in the leaving water pipe
should extend at least 2 in. (50 mm) into the pipe.
Although condenser has an air vent, it is recommended that
a field-supplied air vent be installed in the system to facilitate
servicing. Field-supplied shut-off and balancing valves should
also be installed to facilitate servicing and flow balancing.
Locate valves in inlet and outlet lines as close to the chiller as
possible. Locate air vents at the highest point of the system
loop. See Fig. 13.
Provide drain connections at all low points in the loop to
permit complete system drainage.
30HXC Condenser Temperature Regulating Valve — For
installations where entering condensing water temperature
could be below 70 F (21.1 C), a field-supplied leaving water
temperature regulating valve is required. Operation below 70 F
(21.1 C) without this valve may cause the unit to shut down on
low oil pressure alarms.
NOTE: This valve should be a temperature-controlled valve
(DO NOT USE a pressure-controlled valve) which controls to
80 F (26.7 C) leaving water temperature. A valve that can be
controlled by a 4 to 20 mA signal is also supported by the
Comfort
Link™ control system. Figure 21 shows the installa-
tion details for the regulating valve.
INSTALL PRESSURE RELIEF REFRIGERANT VENT
PIPING — The low side relief valves on all units are provided
with
3
/
4
-in. female NPT connections, and are located on top of
the cooler shell. See Fig. 2-9. There are 2 relief valves for
the cooler; one on each circuit. Make the vent connection to
the low side relief valve by installing a male NPT to copper
OD braze adapter. Braze a 90-degree short-radius elbow
to the adapter. This will allow enough space to make vent
connections to the elbow.
The 30HXA high side relief valves are provided with a
5
/
8
-in. SAE (Society of Automotive Engineers, U.S.A.) flare
connection. The 30HXC high side relief valves are provided
with a
3
/
4
-in. female NPT flare connection, and are located on
the bottom of the condenser shell.
IMPORTANT: Be sure that any Schrader core installed in
the fittings is removed prior to equalizer line installation.
Failure to remove core will result in the unit not function-
ing properly.
CAUTION
Remove any sensors on the condenser nozzles before
welding connecting piping. Reinstall after welding is
complete. Failure to remove these devices may cause unit
damage. Heads are cast iron, welding is
not
recommended.
IMPORTANT: Before starting the unit, be sure all of the air
has been purged from the system.
IMPORTANT: A separate, field-supplied power supply
must be used with the 4 to 20 mA valve. Failure to use a
separate power supply may result in damage to the elec-
tronic chiller components.
IMPORTANT: On brine applications where leaving cooler
water is less than 34 F (1.1 C), a minimum water flow of
0.75 gpm/ton (0.14 L/s per kW) should be maintained
through the condenser at all times.
