Where should the liquid line filter dryer be installed in a typical DX system?

• A. between the evaporator and compressor
• B. after the TXV
• C. between the condenser and metering device
• D. prior to the condenser

Answer: (C)

In a typical DX system, the liquid line filter dryer is placed in the liquid line after the condenser and before the metering device. The main purpose is to remove moisture, acids, and any debris from the liquid refrigerant just before it reaches the expansion device. This protects the metering device (like a TXV) from icing, improper metering, and potential corrosion, while also preventing debris from entering and clogging the throttling orifice.

If the dryer were placed elsewhere, it wouldn’t guard the metering device as effectively. In front of the condenser, it would have to deal with hot, high-pressure vapor rather than liquid, making filtration less reliable. After the metering device, contaminants could already cause improper throttling or damage, and the dryer wouldn’t protect the expansion process. Placing it in other locations doesn’t provide the same protection for the metering device and the overall system.