Reznor YDSA Operation Manual - Manual (Page 23)

Form O-Y P/N 273647R1, Page 23
change the filter drier any time the circuit is opened.
It is recommended to use a tubing cutter when cutting out a filter drier as the
desiccant absorbs and holds moisture better when it is cool. Heat from a torch may
cause moisture to leave the filter and be absorbed in the oil. Be careful to keep
dirt, filings, and other contaminants out of the system.
Continue to
Step 5.
IF the oil measured in Step 2 was significantly less than shown in the table above
or the test for acid in Step 2 did indicate compressor burnout, do the following:
a) Install a liquid line filter drier. If there is acid, install an acid removing filter
drier. Size the acid-removing filter drier at least one capacity size larger than
normally required for the circuit.
b) Install a temporary filter drier in the suction line. When there is acid, a 100%
activated alumina suction filter drier is recommended. The suction line drier
should be sized properly for the circuit and have a service access fitting to
monitor pressure drop across the drier. (NOTE: Suction line filter drier must be
removed after 72 hours of operation.)
Step 12 includes the remaining procedures required for cleanup of a burnout.
Continue to Step 5.
•
Step 5. Braze on Suction and Discharge Lines
CAUTION: Do not leave system open to the atmosphere any longer
than minimum required for installation. POE oil in the compressors is
extremely susceptible to moisture absorption. Always keep ends of
tubing sealed during installation. See Hazard Levels, page 2.
Brazing materials must be able to withstand the high pressure of R-410A
refrigerant. A high temperature, silver phosphate type brazing with 5% or greater
alloy is recommended.
To prevent oxidation, purge tubing with 2-3 psig of regulated dry nitrogen while it
is being brazed. Open the service valve as needed to release the nitrogen. Do not
allow moisture to enter the system.
The installer is responsible for brazing and for complying with appropriate standard
refrigerant piping procedures.
CAUTION: All brazing should be done using a 2-3 psig dry nitrogen
purge flowing through the pipe being brazed.
CAUTION: When brazing, protect all painted surfaces and components
from excessive heat. Wet wrap all valves but do not allow moisture to
enter the tubing. See Hazard Levels, page 2.
•
Step 6. Check System for Leaks
After installation is complete, pressurize the circuit with helium or dry nitrogen to
approximately 150 psi (maximum pressure is 450 psi). Check for leaks using soap
bubbles or other leak-detecting methods.
•
Step 7. Evacuate the Circuit
Evacuate one circuit at a time. Use a vacuum pump and micron gauge. Each
circuit must be evacuated to hold a 500 micron vacuum. Vacuum must be pulled
on both the discharge (high) and suction (low) side. Do the suction side first; and
the compressor discharge side second. To establish that a circuit is leak-free
and moisture-free, a standing vacuum test is recommended. Close off the valve
to the vacuum pump and observe the micron gauge. If the vacuum gauge does
not rise above 500 microns in one minute, the evacuation should be complete.
If the vacuum gauge does rise above 500 microns in one minute, evacuation
is incomplete or the circuit has a leak. Repeat as needed until evacuation is
complete. The evacuation process must be done on each circuit.
NOTE: Evacuation will not remove moisture from POE oil. Moisture must be
prevented from getting in the oil.
Continue and/or repeat Steps 6 and 7 until evacuation is complete.
3.7 Compressor
Operation,
Maintenance,
and
Replacement
(cont'd)