Trane PRGD series, Installation, Operation And Maintenance Manual

Page: 26 / 40

26 PRGD-SVX01F-EN
3. Drain the filter-drier of liquid refrigerant prior to
opening. Use available pressure differential
whenever possible. Connect a refrigeration hose to
the 1/4-inch Schrader drain fitting located on the
drain line isolator valve and also to a service valve
on the chiller evaporator. Open the chiller valve and
drain the filter-drier.
4. Remove the refrigerant vapor from inside the filter-
drier by connecting the suction side of a vacuum
pump to the Schrader drain fitting and the
discharge side to the chiller. Pull a vacuum for
approximately 30 minutes.
N No otte ess::
• Due to the slow out-gassing of refrigerant
from the filter-drier, it will not be possible
to pull and hold a deep vacuum.
• The replacement filter-drier absorbs water
vapor from the ambient air, so it is
shipped with sealing caps on each end.
Do not remove these caps until
immediately before installation.
5. Remove the screws connecting the filter-drier to the
purge base. Loosen the nuts at each end of the
filter-drier and slide it out from the adjacent tubing.
6. Immediately cap the two ends with the caps from
the replacement filter-drier.
7. Dispose of the old filter-drier in accordance with
local regulations.
8. Install the new filter-drier using new O-rings
supplied with the assembly (see the following
figure).
9. Pressurize the purge with dry air or nitrogen to
10 psig (68.9 kPaG) through the Shrader drain
valve. Then check for leaks.
10. Release the pressure, remove hoses, and replace all
valve caps.
11. Set the purge operating mode to “On” and wait for
the purge pump-out compressor to start.
12. Open the isolation valves on the vapor inlet lines
and the liquid return line.
13. After purge pump-out stops, or after several
minutes, return the purge operating mode to Auto
or Adaptive (recommended) using the Tracer®
AdaptiView™ display.
Figure 12. Filter-drier assembly
Inspecting the Moisture
Indicator
Monitor the quality of the liquid refrigerant in the
chiller by periodically inspecting the moisture
indicator. The indicator will show “wet” whenever the
chiller moisture exceeds the levels shown in the
following table. Notice that the indicator becomes
more sensitive as the temperature decreases. (The
moisture indicator normally operates at equipment
room ambient temperatures.)
A “wet” indication for more than 72 hours typically
indicates that the filter-drier is saturated and should be
replaced. In some cases in which a substantial amount
of moisture has accumulated, such as when the chiller
has been serviced, several filter-drier assembly
changes may be required before a satisfactory
moisture level is achieved. A reoccurring or persistent
“wet” indication is a sign of possible chiller air or water
infiltration.
Inspect the moisture indicator only under the following
conditions:
• The chiller is operating.
• The purge unit is operating and has been allowed
sufficient time to properly remove system moisture
(allow a minimum of 72 hours after replacing filter-
drier).
M Ma aiin ntte en na an ncce e