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NOTE: Field installed options may affect low
voltage wire routing. Refer to installation
instructions of field installed options prior to
installing low voltage wiring.
TERMINAL BLOCK - INDOOR UNIT
S1
S2
R
C
G
W1 W2
Y1
R
C
G
W1 W2
Y1
THERMOSTAT
System Start Up
Never operate the compressor with the suction valve
closed to test the compressor's pumping efficiency. In
some cases, this can result in serious compressor damage
and loss of warranty coverage.
For the 7-1/2 ton unit starting charge should be 18 lbs.
of R-410A and 20 lbs. for the 10 ton unit. The length of
line set, indoor unit airflow, condensing unit location and
number of tubing fittings will have an impact on final unit
charge amount. Turn the electrical power on, and let the
system run. Wait for the refrigerant pressures to stabilize.
NOTE: The unit comes with a holding charge of 55 oz.
Charge Verification
REFRIGERANT UNDER PRESSURE!
• Do not overcharge system with refrigerant.
• Do not operate unit in a vacuum or at negative
pressure.
Failure to follow proper procedures may cause property
damage, personal injury or death.
Use refrigerant certified to AHRI standards. Used
refrigerant may cause compressor damage. Most portable
machines cannot clean used refrigerant to meet AHRI
standards.
NOTICE: Violation of EPA regulations may result in fines or
other penalties.
Y2
O
T1 T2
T3
T4
T5
C
BLUE
Y1
YELLOW
PURPLE
PURPLE
PURPLE
Y2
CONDENSER - TWO STAGE AC
Y2
O
WARNING
CAUTION
Damage to the unit caused by operating the compressor
with the suction valve closed is not covered under the
warranty and may cause serious compressor damage.
Final Charge Adjustment
The outdoor temperature must be 60°F or higher. Set the
room thermostat to COOL, fan switch to AUTO, and set the
temperature control well below room temperature.
After system has stabilized per startup instructions, check
subcooling and superheat as detailed in the following
section.
Expansion Valve System
NOTE: Expansion valve bulb must be in place on
suction line & insulated.
Expansion Valve Indoors
At stabilized cooling conditions and with an outdoor
temperature of 60°F or higher, the system should have
from 9°F to 13°F subcooling. For a proper subcooling
reading, measure the refrigerant pressure and temperature
at the outdoor unit's liquid line service valve. If you have
less than 9°F subcooling, slowly adjust the charge by
adding refrigerant. If you have more than 13°F subcooling,
slowly adjust the charge by removing refrigerant. While
reaching the proper subcooling level, it is important to know
the discharge line temperature. This temperature should be
at least 80ºF over ambient or refrigerant could flood back to
compressor.
NOTE: Wait at least 10 minutes before taking
readings and making further adjustments for the
system to stabilize.
Troubleshooting
Qualified Installer/Servicer Only
When troubleshooting, the first step should always be to
check for clean coils, clean filter(s), and proper airflow.
Indoor airflow should be 375 to 425 CFM per ton of
cooling based on the size of the outdoor unit. The most
common way of establishing indoor airflow is heating
temperature rise. Indoor airflow will then be (Heating
output of equipment) / (1.1 x temp. rise). In other cases,
measurement of external static pressure is helpful. For
details, see the Installation Instructions for your indoor unit.
7
CAUTION
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