ClimaCool UCA Manual - Manual (Page 34)

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34
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 charged with R-410A refrigerant. In the
unlikely event that a refrigerant leak is detected at startup,
the following guidelines should be consulted before
reprocessing the refrigeration systems.
Refrigeration System Reprocessing
Debris and moisture can enter copper tubing in a matter
of minutes. All tubing, coil connections, or any refrigerant
containing portions should be temporarily capped or sealed
to keep contaminants to a minimum. Filter driers should
be opened just prior to brazing into the system to prevent
moisture infi ltration whenever possible.
After all of the repairs have been made to the refrigeration
system, a pressure test using refrigerant and nitrogen
should be performed. Pressurize the system with dry
nitrogen to 20 psi and check for any obvious leaks. If no
leaks are present introduce a “trace” amount of refrigerant
to the system (raise system pressure to 30-40 psi). With a
dry nitrogen tank equipped with a regulator set to 550 psi,
continue to pressurize the system to 550 psi. Using a leak
detector, carefully check the system for any remaining leaks.
If the system is free of leaks, you may release the pressure.
Evacuating the System
The compressors should never be run while the system
is in a vacuum. This could cause immediate failure to the
compressors. After the system has been leak tested and
sealed, any moisture that entered the system should be
dehydrated and removed. While the pressure is reduced
under a vacuum, the boiling point of moisture trapped
inside the lines is also reduced. A pressure of .0095 psia, or
500 microns absolute pressure or better must be reached
and sustained for several hours in order for the system to
be considered free from moisture. It is necessary to use a
micron meter equipped with an absolute pressure gauge
(or transducer) to take this reading. ClimaCool recommends
the double evacuation process to ensure proper removal of
moisture and contaminants from the refrigeration system.
After the initial vacuum is reached and held on the system,
allow dry nitrogen back into the system until the pressure
reaches zero psig or slightly higher. Then, repeat the entire
evacuation process described above. The evacuation
process is considered complete ONLY after a successful
“blank-off ” test is performed.
A “blank-off ” test is defi ned as:
a) Pulling a vacuum level less than 500 microns on the
system and holding it for several hours.
b) Record the vacuum level in the system in microns,
then close off the vacuum pump from the system for 15
minutes and continue to monitor the micron level inside
the refrigeration system.
c) If the vacuum level inside the system does NOT rise
more than 400 microns above the recorded vacuum level
at the start of the 15 minute period, then the evacuation
process is complete.
If the vacuum level rises more than 400 microns in 15
minutes, then continue to evacuate the system for 1-2 hours
then repeat a “blank-off ” test.
Recharging the System
After all repairs have been completed, the system has
been leak tested, and proper vacuum pressures have been
reached and maintained, refrigerant may be recharged
into the system. With a known weight of refrigerant in
the cylinder, use the gauge manifold set to connect the
cylinder’s liquid charging port to the charging access port
near the refrigerant liquid line valve. Open the compressor
suction and discharge line valves. Gradually meter the
appropriate weight of liquid refrigerant into the condenser
side of the system fi rst, until no additional refrigerant can
be dispensed. Accurate refrigerant charge per circuit may
be found in the Physical Data information on page 6. Then
continue the charging process by fi lling the evaporator side
of the system with refrigerant. Close the refrigerant cylinder
charging port, close all gauge manifold ports and start the
compressor. Be careful when continuing to charge the
balance of the refrigerant, constantly maintaining a positive
compressor suction pressure (>25 psig) at all times.
WARNING
To avoid the release of refrigerant into the
atmosphere, the refrigerant circuit of this unit must
be serviced only by technicians who meet local, state
and federal profi ciency requirements.
All refrigerant discharged from this unit must be
recovered WITHOUT EXCEPTION. Technicians
must follow industry accepted guidelines and all
local, state and federal statutes for the recovery and
disposal of refrigerants.
If a compressor is removed from this unit, system
refrigerant circuit oil will remain in the compressor.
To avoid leakage of compressor oil, the refrigerant
lines of the compressor must be sealed after it is
removed.
WARNING
This unit contains HFC-(R410A), an azeotropic mixture of R-32 (Difluoromethane) and R-125 (Pentafluoroethane).
DO NOT VENT HFC-(R410A) to the atmosphere. The U.S. Clean Air Act requires the recovery of any residual
refrigerant. Do not use R-22 service equipment or components on R410A systems.
Refrigeration System Re-Processing and Charging