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XP25
Liquid Line Bi-Flow Filter Drier (Heat Pumps only)
Filter-driers come in a variety of sizes, connection types, and materials of construction, but they essentially perform the same
function. All filter-driers contain the same functional parts. They contain desiccants to remove the water and acids, and they
contain a filtration system to remove the solid contaminants.
CHECKOUT:
If the filter drier becomes filled with debris, contaminants, or non-condensables, it restricts refrigerant flow. If the filter drier is
restricted, the outlet side of the filter drier is cooler than the inlet side. Some filter driers have an access port which allows you
to measure the pressure drop with a pressure gauge. If it is restrictive (Greater than 3 psig pressure difference), remove it from
the system and replace it.
Perform a moisture test on the system. If the test indicates moisture levels above what the moisture kit recommends, replace
the drier.
Note - Recommended practice is to replace the filter drier every time you open the system.
STATUS CODES:
None
ERROR CODES:
None
NOTE - If the drier is not operating correctly, the system is shut down by other controls, such as the high and low pressure
switches, which will generate a code.
Figure 47. Top Bi-Flow Filter Drier
