Lennox XP14 Elite Series Installation Instructions Manual page 15

Xk WARNING
7. Shut off the dry nitrogen cylinder and remove the
manifold gauge hose from the cylinder. Open the
manifold gauge valves to release the dry nitrogen from
the line set and indoor unit,
8. Reconnect the manifold gauge to the vacuum pump,
turn the pump on, and continue to evacuate the line set
and indoor unit until the absolute pressure does not
rise above 500 microns (29.9 inches of mercury) within
a 20-minute period after shutting off the vacuum pump
and closing the manifold gauge valves.
9. When the absolute pressure requirement above has
been met, disconnect the manifold hose from the
vacuum pump and connect it to an upright cylinder of
HFC-410A refrigerant, Open the manifold gauge
valves to break the vacuum from 1 to 2 psig positive
pressure in the line set and indoor unit, Close manifold
gauge valves and shut off the HFC-410A cylinder and
remove the manifold gauge set,
power company has been consulted and the voltage
condition has been corrected.
6. Set the thermostat for a cooling demand. Turn on
power to indoor blower unit and close the outdoor unit
disconnect to start the unit.
7. Recheck voltage while the unit is running. Power must
be within range shown on the nameplate.
A IMPORTANT
This system is charged with HFC-410A refrigerant which
operates at much higher pressures than HCFC-22. The
recommended check expansion valve is approved for use
with HFC-410A. Do not replace it with a valve that is
designed to be used with HCFC-22. This unit is NOT
approved for use with coils that include metering orifices or
capillary tubes,
Units are factory-charged with the amount of HFC-410A
refrigerant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with 15 ft.
(4,6 m) line set. For varying lengths of line set, refer to table
3 for refrigerant charge adjustment, A blank space is
provided on the unit rating plate to list the actual field
charge.
IMPORTANT
1. Rotate fan to check for frozen bearings or binding.
2. Inspect all factory- and field-installed wiring for loose
connections,
NOTE - After the system has been evacuated and before
completing all the remaining start-up steps, this is the ideal
time to adjust the amount of refrigerant made necessary by
line set length difference and by the specific indoor unit
match-up, Skip to the paragraph "Setup for Checking and
Adding Charge" on page 16 to setup for charging and for
determining if charge is needed; adjust the charge
accordingly
3. Open the liquid line and vapor line service valves
(counterclockwise) to release refrigerant charge
(contained in outdoor unit) into the system,
4. Replace stem caps and secure finger tight, then
tighten an additional (1/6) one-sixth of a turn,
5. Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit
nameplate. If not, do not start the equipment until the
A IMPORTANT
NOTE - Be sure that filters and indoor and outdoor coils are
clean before testing,
COOLING MODE INDOOR AIRFLOW CHECK
Check airflow using the Delta-T (DT) process (figure 23).
HEATING MODE INDOOR AIRFLOW CHECK
Blower airflow (CFM) may be calculated by energizing
electric heat and measuring:
• temperature rise between the return air and supply air
temperatures at the indoor coil blower unit,
• voltage supplied to the unit,
• amperage being drawn by the heat unit(s),
Then, apply the measurements taken in following formula
to determine CFM:
Amps x Volts x 3.41
CFM =
1.08 x Temperature rise (F)
Check indoor airflow using the step procedures as
illustrated in figure 23.
Page 15
XP14 SERIES