Trane R Series Installation Operation & Maintenance page 107

107
Maintenance Procedures
Tab. XI-01 – Charge Holding Capabilities on High Side
Nominal Nominal Circuit
Capacity Charge lb
70 165
85 175
100 215
120 225
170 365
200 415
240 460
Circuit varies slightly with efficiency and unit configuration
NOTE: Units with a design sequence of
A0 did not have enough capacity in the
condenser to hold the entire charge. Ta-
ble lists the amount of charge that would
flood the oil separator if the charge was
isolated in the high side. For this reason,
when getting the unit back to running
condition, care must be taken to drive
the refrigerant out of the oil separator
using the oil separator heaters.
Returning unit to running condition:
1. Open all valves.
2. Manually open EXV for 15 minutes to
allow refrigerant to drain to evaporator
by gravity (ensure water is flowing in the
evaporator prior to opening the EXV).
3. Let unit sit with heaters on to drive
refrigerant out of oil and warm up com-
pressor bearings. Depending upon am-
bient conditions, this may take up to 24
hours.Ensure the UCM is powered so
the pump may be energized if it detects
a freeze condition.
4. Once the oil level has returned to nor-
mal, the unit can be put back into opera-
tion.
Low side charge isolation procedure:
After normal shut down under some con-
ditions most of the charge resides in the
evaporator. Running cold water through
the evaporator may also drive much of
the
refrigerant to the evaporator.
1. Make sure circuit is off.
2. Close suction line isolation valve.
3. Close oil return line service valve.
4. Close liquid line service valve.
Condenser Charge Charge in Oil
Holding Capacity Separator lb
@ 60% full 90º
ambient lb
118.1 46.9
134.3 40.7
163.7 51.3
187.9 37.1
203.4 161.6
282.0 133
325.6 134.4
5. Manually open EXV.
6. Use a liquid pump or vacuum pump to
move refrigerant from the condenser to
evaporator. The liquid pump will only be
effective if there is a lot of charge in the
condenser. It may be connected to the
condenser drain port on the liquid line
isolation valve.
NOTE: If a pump is to be used, connect
it before closing this valve. This port is
only isolated when the valve is back
seated.
If a vacuum pump is used, then connect
it to the discharge line service valve near
the oil separator. A vacuum pump will be
required for part of the procedure.
% Oil Separator
Level
97.7
86.0
56.0
41.2
100.0%
86.1 %
86.9 %
RTAC-SVX002A-EN