Servicing Units Delivered Void Of Charge; Unit Start−Up; System Refrigerant - Lennox XC21 Installation Instructions Manual

Servicing Units Delivered Void of Charge

If the outdoor unit is void of refrigerant, clean the system
using the procedure described below.
1. Leak check system using procedure outlined on page
16.
2. Evacuate the system using procedure outlined on
page 18.
3. Use nitrogen to break the vacuum and install a new
filter drier in the system.
4. Evacuate the system again using procedure outlined
on page 18.
5. Weigh in refrigerant using procedure outlined in figure
14.
6. Monitor the system to determine the amount of
moisture remaining in the oil. It may be necessary to
replace the filter drier several times to achieve the
required dryness level. If system dryness is not
verified, the compressor will fail in the future.
Unit Start−Up
IMPORTANT
If unit is equipped with a crankcase heater, it should be
energized 24 hours before unit start−up to prevent
compressor damage as a result of slugging.
1. Rotate fan to check for binding.
2. Inspect all factory− and field−installed wiring for loose
connections.
GAUGE SET
CONNECTIONS FOR TESTING AND CHARGING
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 suction line service 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.
SUCTION LINE
B
SERVICE PORT
CONNECTION
REFRIGERANT TANK
CHARGE IN
LIQUID PHASE
DIGITAL SCALE
D TEMPERATURE
SENSOR
Figure 11. Gauge Set Setup and Connections
Page 25
3. After evacuation is complete, open both the liquid and
vapor line service valves to release the refrigerant
charge contained in outdoor unit into the system.
4. Replace the stem caps and tighten to the value listed
in table 1.
5. Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit's
nameplate. If not, do not start the equipment until you
have consulted with the power company and the
voltage condition has been corrected.
6. Set the thermostat for a cooling demand. Turn on
power to the indoor indoor unit and close the outdoor
unit disconnect switch to start the unit.
7. Recheck voltage while the unit is running. Power must
be within range shown on the nameplate.
8. Check system for sufficient refrigerant by using the
procedures listed under System Charge.

System Refrigerant

This section outlines procedures for:
1. Connecting gauge set for testing and charging (see
figure 11.
2. Checking and adjusting indoor airflow as described in
figure 12.
3. Adding or removing refrigerant. Use figure 13 to
determine the best method for charging the system.
When using weigh in method use instructions provided
in figure 14, and verifying charge using methods
provided in figures 15 or 16.
MANIFOLD GAUGE SET
HIGH
LOW
A
C TEMPERATURE SENSOR
(LIQUID LINE)
TO LIQUID
LINE SERVICE
VALVE
OUTDOOR UNIT
XC21 SERIES