Redi Controls Redi-Purge PRG-113-C3, Installation, Operation & Maintenance Manual, Page: 48 / 68

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After replacing filter-drier, you can not rely on a moisture indicator reading to evaluate
refrigerant moisture content until the chiller is operating and th e purge unit has logged at least
72 hours of “Total Purge Condensing Unit Run Time”.
Reading from Moisture Indicator
Ambient
Temperature*
Dry Normal Wet
75 Degrees Less than 5 ppm 5-15 ppm More than 15 ppm
100 Degrees Less than 10 ppm 10-30 ppm More than 30 ppm
125 Degrees Less than 20 ppm 20-50 ppm More than 50 ppm
* Degrees Fahrenheit .
Table 1 -
Determining Refrigerant Moisture Content
If a saturated filter-drier is allowed to remain in the system after the moisture indicator shows
"wet", water will accumulate in the purge tank forming a visible layer on top of the liquid
refrigerant and will be visible in the purge tank sight glass. Any such "free water" must
continually be removed to avoid excessive corrosive conditions in both the purge tank an d the
chiller. To remove "free water" from the purge tank, refer to "Purge Tank Services - Water
Removal" on page 49 in the Maintenance section of this manual.
When the chiller is likely to contain a high level of moisture (e.g., when starting a new chi ller;
or after chiller repairs), the
purge can be temporarily operated with the filter -drier removed to
trap accumulated water in the purge tank. To avoid nuisance trips due to the fault mode (see
the settings operating parameters on page 26 for explanati on ). You may wish to operate the
purge for 24 to 48 hours in the BYPASS mode (see BYPASS Keypad Switch on page 33).
During this “Bypass” period, moisture in the refrigerant will condense and accumulate in the
purge tank where it can then be removed (see “Water Removal Procedure” on page 49).
NOTE: Any "free water" collected in the purge tank must be removed as soon as possible.
When it has been determined that all excessive moisture has been removed, the filter -drier
can be re-installed. However, care should be taken not to install the filter -drier too soon.
Installing the filter-drier too soon will result in premature saturation. (Refer to “Filter -Drier
Replacement” on page 49.)
NOTE: Excessive water collection in the purge tank over a long per iod of time may be an
indication of chiller problems.
NOTE: Disregard moisture indicator readings if your purge is operating while filter -driers are
removed.