Trane CVGF-SVU02B-E4 Operation And Maintenance Manual page 86

Refrigerant Charge
If a low refrigerant charge is
suspected, first determine the
cause of lost refrigerant. Once
the problem is repaired follow
the procedures below for
evacuating and charging the
unit.
WARNING
Hazardous Voltage!
Disconnect all electric power,
including remote disconnects
before servicing. Follow proper
lockout/tagout procedures to
ensure the power can not be
inadvertently energized. Failure to
disconnect power before servicing
could result in death or serious
injury.
Evacuation and Dehydration
1. Disconnect ALL power while
evacuating the system.
2. Connect the vacuum pump to
the 5/8" flare connection on
the bottom of the evaporator.
86
Periodic
Maintenance
3. Remove all of the moisture
from the system to insure a
leak free unit. Pull the system
down below 500 microns (0.5
mm Hg).
4. After the unit is evacuated,
perform a standing rise test
for at least an hour. This
vacuum should not rise more
than 100 microns (0.1 mm Hg)
per hour to a maximum of 500
microns (0.5 mm Hg) over 12
hours. If the vacuum rises
above this, either there is a
leak or the unit has moisture
present.
Note: If oil is in the system, this
test is more difficult. The oil is
aromatic and will give off vapors
that will raise the pressure of the
system. Check for oil
temperature >122°F (50°C).
Refrigerant Charging
Once the system is leak and
moisture free, use the 5/8" flare
connections at the bottom of the
evaporator and side of
condenser to add refrigerant
charge. See Unit Nameplate for
correct refrigerant charge
amounts.
Add the refrigerant charge as a
vapor until the system pressure
is above 29.4 psi (203 kPa) or
Temperature is above 34°F (1°C).
Liquid refrigerant may be added
once these conditions are
achieved.
CAUTION
Possible Freeze-up
Water can freeze during charging.
Circulate water during charging to
prevent freezing.
Caution
Charge vapor in the unit
until:
• System pressure is above 29.4
psig (203 kPa )
• The saturation temperature of
R134a is above 34°F (1°C)
CVGF-SVU02B-E4