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Important: Do Not release refrigerant to the atmosphere! If
adding or removing refrigerant is required, the
service technician must comply with all
federal, state, and local laws.
•
To prevent cross contamination of
refrigerants and oils, use only dedicated R-
410A service equipment.
•
Disconnect unit power before evacuation
and do not apply voltage to compressor
while under vacuum. Failure to follow
these instructions will result in compressor
failure.
•
Due to the presence of POE oil, minimize
system open time. Do not exceed 1 hour.
•
When recharging R-410A refrigerant, it
should be charged in the liquid state.
•
The compressor should be off when the
initial refrigerant recharge is performed.
•
Charging to the liquid line is required prior
to starting the compressor to minimize the
potential damage to the compressor due to
refrigerant in the compressor oil sump at
startup.
•
If suction line charging is needed to
complete the charging process, only do so
with the compressor operating. Do not
charge liquid refrigerant into the suction
line with the compressor off! This
increases both the probability that the
compressor will start with refrigerant in the
compressor oil sump and the potential for
compressor damage.
•
Allow the crankcase heater to operate a
minimum of 8 hours before starting the
unit.
Charge Storage
Due to the reduced capacity of the microchannel
condenser coil compared to the round tube plate fin
evaporator coil, pumping refrigerant into the condenser coil
to service the refrigerant system is no longer an option.
RT-SVX063G-EN
Service and Maintenance
Refrigeration Pressure Curves
Please refer to
"Pressure Curves," p. 112
curve that corresponds to the unit's refrigeration system.
This plot will indicate the approximate discharge line
pressure which should be observed at a given outdoor
ambient dry bulb temperature and suction pressure when
the unit has the correct amount of subcooling (indicating
that it is properly charged.)
For meaningful use of the Pressure Curve charts, please
refer to the following:
•
Ensure outdoor ambient temperature is between 65°F
and 105°F, and that the air entering the evaporator is at
least 40% Relative Humidity.
•
Ensure all condenser fans are running at full speed for
the circuit you are testing, and that the Hot Gas Bypass
Valve is fully closed (if applicable to your system.)
•
Verify that the Hot Gas Reheat Valve (if applicable) is
set to 0% reheat.
•
Pressures curves represent 100% compressor capacity
as displayed at unit touch pad. All compressors must
be running and variable speed compressors must not
be speed limited due to discharge pressure or current.
Note that depending on unit size, variable speed
compressor RPM typically is less than 6000 RPM at
100% unit compressor capacity.
Measuring Subcooling
1. At the liquid line service port, measure the liquid line
pressure. Using an R-410A pressure/temperature
chart, convert the pressure reading into the
corresponding saturated temperature.
2. Measure the actual liquid line temperature as close to
the liquid line service port as possible. To ensure an
accurate reading, clean the line thoroughly where the
temperature sensor will be attached. After securing the
sensor to the line, insulate the sensor and line to isolate
it from the ambient air. Use a thermocouple type probe
for an accurate reading.
3. Determine the system subcooling by subtracting the
actual liquid line temperature (measured in step 2) from
the saturated liquid temperature (converted in step 1.)
to locate the
111
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