ClimaCool IOM AR2 SERIES - Manual (Page 51)

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Discharge Line Piping Recommendations
All discharge lines should be kept as short as possible, and the
line sizing is determined to provide for a low-pressure drop .
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 discharge 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 90° elbows) should not exceed 100 feet . Vertical
discharge lines greater than 5 feet require a “P”-trap at the base
of the riser as well as an inverted trap at the top of the discharge
line run (see Figure on page 32) . The inverted trap should be
the highest point in the discharge line . Additional “P”-traps
should be added at every 10 feet of additional vertical rise in the
discharge line . The maximum vertical distance between the lower
AR2 module section and the higher remote condenser location
should be less than 50 feet . AR2 modules equipped with optional
compressor unloading by means of hot gas bypass/combination
liquid injection require the use of double risers for vertical
discharge line runs (see Figure 3 on page 32) .
Remote Condenser Piping Connections
The discharge and liquid line connections at the remote condenser
section are equipped with capped, stub-out tubes . It is mandatory
that isolation ball valves and check valves are field installed at
BOTH the inlet and outlet connection locations of each remote
condenser . These ball valves and check valves are shipped loose
with every ClimaCool AR2 split system chiller package . Refer to
Figures on pages 33 and 34 for schematic representation of the
isolation and check valve functions .
Leak Testing - Refrigeration Side
Prior to startup, the entire system should be leak tested using
electronic leak detection . Carefully leak test both factory and
field made joints including condenser coils . Although each unit is
factory leak tested, joints do loosen and sometimes break during
shipment .
Refrigeration System Reprocessing
Once a refrigeration system has been exposed to atmosphere for
any length of time (several minutes to an hour), it is imperative
that the system undergo a thorough evacuation to remove
moisture and non-condensibles . With split systems, provisions
should be made to evacuate the interconnecting discharge and
liquid lines prior to opening the shutoff valves provided in each
section . Noncondensibles (air, nitrogen trace gases, etc .) trapped
in the system will elevate condensing pressures . This will result
in inefficient system operation and potentially cause nuisance
head pressure trips . Moisture in the system can cause chemical
reactions with many POE oil additives resulting in the formation
of undesirable acids which corrode the system .
IMPORTANT: NEVER start the compressor while in a
vacuum. Serious damage can occur to the motor windings
in this condition. Only use a vacuum pump of known reliable
operation, specifically, one that can achieve a vacuum level of
100-200 microns with the pump service port closed . Prior to
evacuation, make sure all refrigerant isolation valves are OPEN,
and that the main liquid line solenoid valves are energized
(apply 24VAC to the solenoid coils using a 75VA transformer
or equivalent) . Alternatively, you may choose to manifold
multiple evacuation hoses together and connect vacuum lines
to refrigeration access fittings on both sides of the liquid line
solenoid valves . Ensure that the vacuum pump is connected
to both high and low sides of the system with copper tube or
vacuum hoses . A vacuum gauge capable of reading vacuum
levels in microns (with readability as low as 100 microns) must
be connected to the system, preferably close to the compressor
module . Ordinary gauges from a standard charging manifold
are unacceptable! Operate the vacuum pump until a vacuum
level below 500 microns is achieved . Close the vacuum pump
service valves to isolate the pump from the refrigeration system .
This initiates a “vacuum decay test” by monitoring system
pressure rise for a time period of 15 minutes . The refrigeration
system vacuum gauge should not rise more than 200 microns
within this 15 minute period . Pressures that rise beyond this
decay criteria indicate the existence of a leak, or more likely,
indicate the presence of moisture or non-condensibles in the
system . If a leak is suspected, it must be identified and corrected
before proceeding with the evacuation . If moisture contamination
is the suspected problem, rapid evacuation processes may serve
only to freeze the moisture inside the system, allowing only for
the slow process of sublimation to remove all of the water . Then
it is recommended to apply sun lamps to the compressor and
receiver to elevate the temperature inside the system above the
freezing point while evacuating . Successive dry nitrogen fills
and purges can prove equally beneficial in removing excessive
moisture form a system .
Split System Interconnecting Piping