ClimaCool UCR 30, 50 and 70 tons Manual - Manual (Page 52)

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52
Copper Tubing, Brazing and System
Reprocessing Recommendations
Copper tubing must be refrigeration grade (ACR type
“L”). Be sure to install appropriate copper fi ttings rated
for ACR applications. Never leave refrigerant lines open
when they are not directly being installed. Never rely on
the last refrigerant connection joint at a specifi c section
(UCR module or condenser section) to provide structural
support for the interconnecting piping. Line pulsation may
occur at start-up and shut down of scroll compressors.
Additional line support may be required to prevent
vibration transmission or movement in the line. Ensure that
all interconnecting piping is properly and independently
braced at 7 feet minimum intervals, and within 2 feet from
each section’s fi nal connection location, to prevent joint
fracture due to line vibrations or liquid hammering.
Use 15% silver-phosphorus braze fi ller rod when brazing
copper-to-copper joints. When brazing copper-to-brass
joints, apply “sta-silv” brazing paste (or equivalent)
sparingly to the joint areas, and use 45% silver-phosphorus
braze fi ller rod. Always purge a generous fl ow of dry
nitrogen (approximately 10 CFH) through the lines while
brazing to prevent internal scaling of copper oxide on
heated copper surfaces exposed to air.
When sizing the interconnecting refrigerant lines, never
use the stub-out sizes at the UCR module section as your
determining factor. For proper operation, all discharge
and liquid lines must be sized in accordance with the
recommendations provided in the following piping
sections. After installing the interconnecting piping,
proper system evacuation and reprocessing guidelines are
provided in the Refrigeration System Reprocessing section
of the Split System Interconnecting Piping on page 54.
Liquid Line Piping Recommendations
All liquids should be kept as short as possible, and the line
sizing is determined to provide for a low-pressure drop
to prevent liquid line fl ashing. There should always be a
gradual negative elevation change when traversing from
the remote condenser location to the UCR
module section. Avoid any reversing elevation changes
throughout this liquid line run. Horizontal liquid lines
should be sloped downward in the direction of refrigerant
fl ow at a pitch of 1/8” per foot. The total equivalent
distance between the condenser and the UCR section
(including allowances for U-bends and 90° elbows) should
not exceed 100 feet. Avoid routing liquid lines through
heated spaces which may result in undesirable fl ash gas
generated at the TXV inlet. Avoid insulating liquid lines.
Refrigeration System Re-Processing
Conforming to local and national codes is the responsibility
of the service technician or installing contractor. The
service technician should be familiar with the following
codes:
• ASHRAE Standard Safety Code for Mechanical
Refrigeration, ANSI/ASHRAE 15-1978
• American National Standard Code for Pressure Piping,
ANSI B31.5-1974
Factory Tested
ClimaCool modular chillers have been pressure-tested,
evacuated and both refrigeration circuits pressurized
with 50 psig of dry nitrogen prior to shipment. The split
system chillers require interconnecting refrigeration piping
between the ClimaCool UCR modular remote air cooled
chiller and the remote condenser section. The condenser
section provided by ClimaCool is typically a remote air-
cooled condenser confi guration. Contact the factory for
guidelines for customer supplied, fi eld integration to
other permissible condenser types, such as evaporative
condenser confi gurations. The refrigerant charge will
be weighed-in in the fi eld based on the condenser
confi guration and condenser model. The ClimaCool
UCR030 model is equipped with a 72 pound liquid receiver
capacity per compressor circuit. The UCR050 and UCR070
models have an 84 pound liquid receiver installed per
circuit. All ClimaCool “UCR” models MUST be charged
with R-410A refrigerant. Field installation of additional
receiver capacity may be required depending on the
refrigerant retaining volume of the remote condenser
and interconnecting piping. After the total refrigerant
amount is charged into each circuit (weighed in using
an appropriate refrigeration scale), the resultant weight
should be recorded on the UCR module data plate for
future reference. See Refrigerant Charging Procedure –
page 55 for specifi c charging guidelines.
UCR Modular Chiller Refrigeration Piping
Connections
The discharge and liquid line stub-out connections at the
UCR module section are equipped with shut-off valves
with capped leads. Never uncap these leads without
checking the shutoff valves to be sure that they are
fully closed and the units are ready for piping. All scroll
compressors in ClimaCool UCR modules are equipped with
POE refrigeration oil. Systems with compressors using
POE oils must be kept closed at all times except when the
interconnecting piping is being directly installed. POE oils
are extremely hydroscopic in nature and will absorb an
undesirable amount of moisture from normal ambient air
within a few minutes.