System Refrigerant; Gauge Set Connections - Lennox XP25-024-230-01 Installation And Service Procedure

System Refrigerant

IMPORTANT !
The system must be operating at full capacity during
charging. Increase (heat) or decrease (cooling) the
thermostat setting by 5°F to create system demand.
Confirm outdoor unit running capacity on the display
on the outdoor control. Value should be 100%.
This section outlines procedures for:
1. Connecting gauge set for testing and charging as
illustrated in figure 63.
2. Checking and adjusting indoor airflow as described in
figure 64.
3. Adding or removing refrigerant using the weigh-in
method shown in figure 65, and verifying charge using
subcooling method described in figure 66.
GAUGE SET
CONNECTIONS FOR TESTING AND CHARGING
INSIDE OUTDOOR UNIT
A
CLOSE MANIFOLD GAUGE SET VALVES AND CONNECT THE CENTER HOSE TO A CYLINDER OF HFC-410A. SET FOR LIQUID PHASE CHARGING.
B
CONNECT THE MANIFOLD GAUGE SET'S LOW PRESSURE SIDE TO THE TRUE SUCTION PORT.
C
CONNECT THE MANIFOLD GAUGE SET'S HIGH PRESSURE SIDE TO THE LIQUID LINE SERVICE PORT.
D
POSITION TEMPERATURE SENSOR ON LIQUID LINE NEAR LIQUID LINE SERVICE PORT.
TRUE SUCTION PORT
B
CONNECTION
REFRIGERANT TANK
CHARGE IN
LIQUID PHASE
DIGITAL SCALE
D
TEMPERATURE
SENSOR
Figure 63. Gauge Set Connections
Page 85
IMPORTANT - Unit must be operating at 100% input to
charge 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.
COOLING MODE INDOOR AIRFLOW CHECK
Check airflow using the Delta-T (DT) process using the
illustration in figure 64.
The diagnostic screen on the thermostat or outdoor control
7-Segment display shows indoor and outdoor motor CFMs
or RPMs.
MANIFOLD GAUGE SET
HIGH
LOW
A
C
TO LIQUID
TEMPERATURE SENSOR
LINE SERVICE
(LIQUID LINE)
VALVE
OUTDOOR UNIT
XP25