Desert Aire SA Series, Installation And Operation Manual

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• Do not use acid neutralizing additives or other chemicals for acid removal. The refrigeration
system must contain only oil and refrigerant. Precipitates of additives and acids may be
considered contamination in the refrigeration system. Other compounds may be present in
additives as carriers. Longterm effects of specific additives or compounds with a particular
system or design are unknown without significant controlled testing.
Particulate Indicated
• Install a replaceable core liquid line filter shell. Note that larger Desert Aire systems will have
replaceable core liquid line filter shells installed from the factory. The pressure drop
levels will be monitored and several core changes may be required. Install ball valves on either
side of the filter shell to facilitate these changes.
• Install a secondary filter such as Sporlan FS-series or equivalent 20 micron filter in the
replaceable core.
• Ensure there are access fittings directly upstream and downstream of the liquid filter. There is
typically one fitting installed on the filter shell. There is typically one fitting installed on the
outlet side of the receiver.
Returning to Service
• See Section 5.6 for evacuation and charging.
• Restart unit and set unit to run compressors.
• Record the pressure drop across the suction filter and liquid line filter dryer.
• Check sight-glass indicator for moisture level.
• Monitor pressure drop across the liquid and suction filters during the first hour of operation.
Compare the reading taken earlier. If the pressure differential across the filters is more than 5 PSI
greater than the initial reading, isolate the filters using the valves installed and recover the
refrigerant from the filters. Replace cores. If activated carbon filters were installed in the suction
side to remove acid, replace with similar cores. If a secondary filter was installed in the liquid line
core to remove particulate, install cores and secondary filter in this location.
• Run unit for 24 hours and review acid levels (if found previously) and pressure differentials.
- If acid is found, replace with activated charcoal cores and test at 24 hour intervals until
acids are at acceptable levels. Once acid is no longer detected, replace cores
with standard filter elements. Remove outlet screens if they were required by
filter manufacturer.
- If the pressure differential across the liquid line filter is more than 5 PSI greater than the
initial reading, replace cores and secondary filter with new components and test
at 24 hour intervals until pressure drop is at acceptable levels. Once pressure differential
is less than 5 PSI, remove secondary filter and replace cores.
Testing and Final Diagnosis
It is of critical importance to ensure that the system is operating as expected before unit is returned to
normal service. Complete a Compressor Replacement Form located in the Installation and Operation
Manual. Validation of this report allows for the continued coverage of the compressor under the
original warranty.
Desert Aire - SA Manual