Lennox International Inc. 10ACB - Manual (Page 8)

3DJH 
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IMPORTANT
Crankcase heater (used on 3--1/2, 4 and 5 ton
units) should be energized 24 hours before unit
start--up to prevent compressor damage as a re-
sult of slugging.
1-- Rotate fan to check for frozen bearings or binding.
2-- Inspect all factory and field-installed wiring for
loose connections.
3-- After evacuation is complete, open liquid line and
suction line service valves to release refrigerant
charge (contained in condensing unit) into the sys-
tem.
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 unit
nameplate. If not, do not start the equipment until
the power company has been consulted and the
voltage condition corrected.
6-- Set the thermostat for cooling demand, turn on
power to evaporator blower and close condensing
unit disconnect switch to start unit.
7-- Recheck voltage with unit running. Power must be
within range shown on nameplate. Check amper-
age draw of unit. Refer to unit nameplate for cor-
rect running amps.
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Units are factory charged with the amount of HCFC-22
refrigerant indicated on the unit rating plate. This
charge is based on a matching indoor coil and outdoor
coil with 20 ft. (6.1m) line set. For varying lengths of line
set, refer to table 3 for refrigerant charge adjustment. A
blank space is provided on the rating plate to list the ac-
tual field charge.
Liquid Line
Set Diameter
Ozs. per 5 ft. (ml per mm) adjust
from 20 ft. (6.1m) line set*
3/8 in.
(10mm)
5/16 in.
(8mm)
2 ounce per 5 ft.
(57ml per 1.5m)
3 ounce per 5 ft.
(85ml per 1.5m)
*If line length is greater than 20 ft. (6.1m), add this amount. If
line length is less than 20 ft. (6.1m), subtract this amount.
TABLE 3
If the system is void of refrigerant, the recommended
and most accurate method of charging is to weigh the
refrigerant into the unit according to the total amount
shown on the unit nameplate. This may be done after
any leaks have been repaired. If weighing facilities are
not available or if unit is just low on charge, use one of
the procedures outlined.
Charging a condensing unit is recommended during
warm weather. However, applications arise in which
charging must occur in the colder months. The way the
unit is charged depends on the unit’s refrigerant me-
tering device and the outdoor ambient temperature.
For RFC systems, weighing in the charge and subcooling
are two acceptable means of charging under certain
conditions. For installations of an RFC system where the
outdoor ambient is less than 65-F (18-C), weighing in the
charge is the best method. However, in installations
where the outdoor ambient is 65-F (18-C) or above, sub-
cooling is the best method.
Weighing in the charge and the approach method are
the two recommended procedures for charging the
10ACB using an expansion valve system for refrigerant
metering. The difference between the two involves the
outdoor ambient temperature. For expansion valve
systems where the outdoor ambient temperature is
60-F (16-C) or above, the approach method may be
used. For expansion valve systems where the outdoor
ambient temperature is below 60-F (16-C), weighing in
the charge is recommended.