Lennox XC25 – System Refrigerant

This section outlines the procedures to:
1. Connect a gauge set for testing and charging as illustrated in fig­ure 55.
2. Check and adjust indoor airflow as described in figure 56.
3. Add or remove refrigerant using the weigh-in method shown in figure 57.

4. Verify the charge using the subcooling method described in fig­ure 58.

IMPORTANT: Unit must be operating at 100% input to be charged properly.

ADDING OR REMOVING REFRIGERANT
This system uses HFC-410A refrigerant which operates at much higher pressures than HCFC-22. The pre-installed liquid line filter drier is approved for use with HFC-410A only. Do not replace it with components designed for use with HCFC-22.

INDOOR AIRFLOW CHECK
Check airflow using the Delta-T (DT) process using the illustration in figure 56.
The diagnostic screen on the thermostat or outdoor control 7-seg­ment display shows indoor and outdoor motor CFMs or RPMs.

Use the WEIGH-IN method for adding initial refrigerant charge, and then use SUBCOOLING method for for verifying refrigerant charge.