11-AC40D1-1E-EN
19
Subcooling Charging in Cooling between 55° F and 120°
OD Ambient
[brand name] has always recommended installing
[brand name] approved matched indoor and outdoor
systems.
The benefits of installing approved indoor and outdoor
split systems are maximum efficiency, optimum
performance and the best overall reliability.
The following charging methods are therefore
prescribed for matched systems with indoor TXVs/
EEVs.
1. Subcooling (in the cooling mode) is the only
recommended method of charging above 55°
ambient temperatures.
2. For best results — the indoor temperature should
be kept between 70° to 80° F. Add system heat if
needed.
3. At startup, or whenever charge is removed or
added, the system must be operated for a minimum
of (20) minutes to stabilize before accurate
measurements can be made.
4. Measure Liquid Line Temperature and Refrigerant
Pressure at service valves.
5. Determine total refrigerant line length, and height
(lift) if indoor section is above the condenser.
6. Determine the Design Subcooling Charging
Temperature from the unit nameplate.
7. Locate this value in the appropriate column of the
Subcooling Charging Table. Locate your liquid line
temperature in the left column of the table, and the
intersecting liquid line pressure under your
nameplate subcool value column. Add refrigerant
to raise the pressure to match the table, or remove
refrigerant to lower the pressure. Again, wait (20)
minutes for the system conditions to stabilize
before adjusting charge again.
8. When system is correctly charged, you can refer to
System Pressure Curves to verify typical
performance.
