Allied Air 4AC18LT Series, Installation And Maintenance Instructions Manual

Page: 13 / 24

506469-01 Issue 1008
START-UP
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 outdoor unit) into system.
4. Replace the stem caps and secure finger tight, then
tighten an additional 1/6 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 equipment until the power company has
been consulted and the voltage condition corrected.
6. Set thermostat for cooling demand, turn on power to
indoor blower, and close the outdoor unit disconnect switch
to start the unit.
7. Recheck unit voltage with unit running. Power must be
within range shown on unit nameplate.
Refrigerant Charging
This system is charged with R410A refrigerant which
operates at much higher pressures than R-22. The liquid
line drier provided with the unit is approved for use with
R410A. Do not replace it with one designed for use with R-
22.
This unit is NOT approved for use with coils which
use capillary tubes as a refrigerant metering device.
R410A refrigerant cylinders are rose colored. Refrigerant
should be added through the suction valve in the liquid state.
Certain R410A cylinders are identified as being equipped
with a dip tube. These allow liquid refrigerant to be drawn
from the bottom of the cylinder without inverting the cylinder.
Do not turn this type of cylinder upside down to draw
refrigerant.
Units are factory charged with the amount of R410A
refrigerant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with 15’
line set. For varying lengths of line set, refer to Table 5 for
refrigerant charge adjustment. A blank space is provided
on the unit rating plate to list the actual field charge.
Table 5
If the system is void of refrigerant, clean the system using
the procedure described below.
1. Use dry nitrogen to pressurized the system and check
for leaks. Repair leaks, if possible.
2. Evacuate the system to remove as much of the moisture
as possible.
3. Use dry nitrogen to break the vacuum.
4. Evacuate the system again.
5. Weigh the appropriate amount of R410A refrigerant (listed
on unit nameplate) into the system.
6. Monitor the system to determine the amount of moisture
remaining in the oil. Use a test kit to verify that the moisture
content is withing the kit’s dry color range. 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.
The outdoor unit should be charged during warm weather.
However, applications arise in which charging must occur in
the colder months. The method of charging is determined
by the unit’s
refrigerant metering device and the outdoor
ambient temperature.
Measure the liquid line temperature and the outdoor ambient
temperature as outlined below:
Page 13 of 24
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.
CAUTION
Mineral oils are not compatible with R410A. If oil must
be added, it must be a polyolester oil.
IMPORTANT
3/8 in.
3 oz. Per 5 ft.
Liquid Line Set
Diameter Oz. per 5 ft. adjust
from 15 ft. line set*
Refrigerant Charge Adjustment
* If line length is greater than 15 ft., add this amount.
If line length is less than 15 ft., remove this amount.