Filter Drier Restriction Test Procedure

Purpose:
To determine if a filter drier is restricted and requires replacement.

Step 1: Preparation

• Verify the system is running and stabilized before starting the test.

• Locate and identify the inlet and outlet sides of the filter drier.

Step 2: Temperature Measurement

• Use a calibrated thermometer or temperature probe for accurate readings.

• Measure the temperature at the inlet of the filter drier.

• Measure the temperature at the outlet of the filter drier.

Step 3: Temperature Differential Analysis

• Calculate the temperature difference (ΔT) between the inlet and outlet readings.

Step 4: Evaluation Criteria

• Acceptable Range: ≤ 2°F difference (considering meter accuracy).

• Unacceptable Range: > 2°F difference — Indicates a potential restriction.

Step 5: Corrective Action

• If the ΔT exceeds 2°F:

  • Replace the filter drier.

  • Retest the system to confirm the new filter drier is functioning properly.