ClimaCool IOM AR2 SERIES - Manual (Page 50)

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REFRIGERATION SYSTEM REPROCESSING
All ClimaCool remote air-cooled modular chillers leave the
factory with both refrigeration circuits pressurized with 50 psig of
dry nitrogen . These split system chillers require interconnecting
refrigeration piping between the ClimaCool AR2 compressor/
evaporator module section and the remote condenser section .
The condenser section provided by ClimaCool is typically a
remote air-cooled condenser configuration . Contact the factory
for guidelines for customer supplied, field integration to other
permissible condenser types, such as evaporative condenser
configurations . The refrigerant charge will be weighed-in in the
field based on the condenser configuration and condenser model .
The ClimaCool AR2-25 and AR2-30 models are equipped with
a 72 pound liquid receiver capacity per compressor circuit . The
AR2- 50 and AR2-65 models have an 84 pound liquid receiver
installed per circuit . The installing contractor MUST make the
determination of refrigerant type to be charged in the field . All
ClimaCool AR2 module systems can be charged with either
refrigerant R-22 or R-407C . 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 at
+/- 2 pound accuracy), the resultant weight should be recorded
on the AR2 module data plate for future reference . See “System
Refrigerant Charging” section for specific charging guidelines .
AR2 Module Refrigeration Piping Connections
The discharge and liquid line stub-out connections at the AR2
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 AR2 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 .
Copper Tubing, Brazing and System Reprocessing
Recommendations
Copper tubing must be refrigeration grade (ACR type “L”) .
Be sure to install appropriate copper fittings 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 specific section (AR2 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’ minimum intervals, and within 2’ from each section’s
final connection location, to prevent joint fracture due to line
vibrations or liquid hammering .
Use 15% silver-phosphorus braze filler 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 filler rod . Always
purge a generous flow of dry nitrogen (approx . 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 AR2 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 section titled, “Refrigeration System
Reprocessing” .
Liquid Line Piping Recommendations
All liquid lines should be kept as short as possible, and the line
sizing is determined to provide for a low-pressure drop to prevent
liquid line flashing . There should always be a gradual negative
elevation change when traversing from the remote condenser
location to the AR2 module section . Avoid any reversing
elevation changes throughout this liquid line run . Horizontal
liquid lines should be sloped downward in the direction of
refrigerant flow at a pitch of 1/8” per foot . The total equivalent
distance between the condenser and the AR2 section (including
allowances for U-bends and 90o elbows) should not exceed 100
feet . Avoid routing liquid lines through heated spaces which may
result in undesirable flash gas generated at the TXV inlet . Avoid
insulating liquid lines .
Refrigeration System Reprocessing