20
RT-SVF69C-EN
Pressure Curves
Refrigerant Charging Procedure
1.
Weigh the refrigerant charge into the liquid line
Schrader fitting. Proper unit charge is listed on the unit
serial data plate.
2. Liquid line charging is the preferred charging method
to minimize starting the compressor with liquid
refrigerant in the compressor oil sump. Never charge
liquid into the low side of the system while the
compressor is not operating. Never charge refrigerant
into the compressor discharge schrader fitting.
3. R-410a must only be charged in the liquid state.
To Check Operating Pressures
1.
Enter the stage of the “Service Test Mode” of the unit
that brings on all compressors in the cooling mode.
Allow all compressors to run long enough for the
pressures to stabilize.
2. Measure the liquid line temperature of each circuit
near the condenser coil after pressures stabilize.
3. Measure the liquid line pressure of each circuit after
pressures stabilize.
4. Use the chart below to plot the measurements taken
and to determine any charge adjustment.
WARNING
Refrigerant under High Pressure!
System contains oil and refrigerant under high
pressure. Recover refrigerant to relieve pressure before
opening the system. See unit nameplate for refrigerant
type. Do not use non-approved refrigerants, refrigerant
substitutes, or refrigerant additives. Failure to recover
refrigerant to relieve pressure or the use of non-
approved refrigerants, refrigerant substitutes, or
refrigerant additives could result in an explosion which
could result in death or serious injury or equipment
damage.