INSTALLATION INSTRUCTIONS
R−410A, Two−Stage Split System Air Conditioner
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9
AIRFLOW SELECTION
Two−stage compressor operation requires two different
indoor airflow settings for proper operation. This outdoor
unit is designed for use only with an indoor blower that can
be configured for separate low−stage and high−stage
airflow (CFM) levels. Refer to Product Specifications
Sheets for recommended low−stage and high−stage
indoor airflow values. Refer to indoor unit Installation
Instructions to set the indoor blower for the proper
low−stage and high−stage airflow values.
NOTE: Optimal comfort, efficiency, and reliability will only
be achieved when the indoor airflow is properly set for
both low−stage and high−stage operation.
START−UP PROCEDURE
1.
Set indoor thermostat selector switch to OFF.
2.
Turn ON all electrical disconnect devices.
3.
Unit has a crankcase heater. Energize the heater and
wait 24 hours before proceeding.
4.
Set indoor thermostat at desired temperature. Be
sure setpoint is below indoor ambient temperature or
thermostat will not call for cooling.
5.
Set indoor thermostat selector switch to COOL.
Operate unit for minimum 25 minutes, then check the
system refrigerant charge.
REFRIGERANT CHARGE
NOTE: Charge in High−Stage only.
Outdoor units are shipped with a refrigerant charge to
match a specific indoor coil and 15 feet (4.6m) of
refrigerant line. If shorter or longer refrigerant lines or a
different indoor coil are used, the charge will have to be
adjusted.
For different line lengths, add or remove charge based on
0.6 ounces (17g) charge per foot (305mm) of difference.
For example, a 25 foot (7.6m) line set is 10 feet (3m)
longer than the specified 15 feet (4.6m). Add 0.6 ounces
(17g) charge for each of the extra 10 feet (3m):
10 x 0.6 = 6.0 ounces additional charge
(3m x 17g = 51g additional charge)
This outdoor unit is designed for use only with indoor coils
that utilize a TXV refrigerant metering device. With an
indoor TXV, use the subcooling method to make final
charge adjustments:
NOTE: Only use subcooling charging method when
outdoor ambient temperature is between 70
F and 100
F
(21
C and 38
C)
indoor temperature is between 70
and 80
F (21
C and
27
C)
line set is less that 80 feet (24.4m).
1.
Operate unit a minimum of 25 minutes in
high−stage before checking charge.
NOTE: Outdoor unit has a 2−speed fan motor.
Motor will operate in low speed when outdoor
ambient temperature is below 82
°
F (28
C). Pull
one of the yellow low voltage wires off the fan
control and the unit will default to high speed fan for
servicing. Reconnect wire after servicing.
2.
Measure liquid service valve pressure by attaching
an accurate gauge to service port.
3.
Measure liquid line temperature by attaching an
accurate thermistor type sensor or electronic
thermometer to liquid line near outdoor coil.
4.
Refer to unit rating plate for required subcooling
temperature.
5.
Refer to Figure 11. Find the required liquid line
temperature where the rating plate subcooling
temperature intersects measured liquid service
valve pressure.
6.
If the measured liquid line temperature is higher
than the chart number, add refrigerant to lower the
measured temperature.
NOTE: When adding refrigerant, charge in liquid form,
using a flow restricting device, into the suction port. If the
measured liquid line temperature is lower than the chart
number, reclaim refrigerant to raise the measured
temperature.
Tolerance is
3
°
F (
1.7
°C)
.
