68
YORK INTERNATIONAL
The refrigerant charge is specified for each Millennium
model (see Table 5). Charge the correct amount of refrig-
erant and record the level in the cooler sight glasses.
The refrigerant charge should always be checked and
trimmed when the system is shut down.
The refrigerant charge level must be checked after the pres-
sure and temperature have equalized between the con-
R-134A
(lbs.)
temperature will return to approximately ambient tem-
perature. Close off the system again, and start the sec-
ond evacuation.
The relatively small amount of moisture left will be carried
out through the vacuum pump and the temperature or pres-
sure shown by the indicator should drop uniformly until it
reaches a temperature of 35°F or a pressure of 5 mm Hg.
When the vacuum indicator registers this temperature or
pressure it is a positive sign that the system is evacu-
ated and dehydrated to the recommended limit. If this
level can not be reached, it is evident that there is a leak
somewhere in the system. Any leaks must be corrected
before the indicator can be pulled down to 35°F or 5 mm
Hg. in the primary evacuation.
During the primary pull down keep a careful watch on the
wet bulb indicator temperature, and do not let it fall below
35°F. If the temperature is allowed to fall to 32°F the wa-
ter in the test tube will freeze, and the result will be a
faulty temperature reading.
To avoid the possibility of freezing the liquid within the
cooler tubes when charging an evacuated system, only
refrigerant vapor from the top of the drum or cylinder must
be admitted to the system until the system pressure is
raised above the point corresponding to the freeze point
of the cooler liquid. For water, the refrigerant pressure
corresponding to the freezing point is 30 PSIG for R134a
(at sea level.)
While charging, every precaution must be taken to pre-
vent moisture laden air from entering the system. Make
up a suitable charging connection from new copper tub-
ing to fit between the system charging valve and fitting on
the charging drum. This connection should be as short
as possible but long enough to permit sufficient flexibility
for changing drums. The charging connection should be
purged each time a full container of refrigerant is con-
nected and changing containers should be done as quickly
as possible to minimize the loss of refrigerant.
REFRIGERANT CHARGING
Refrigerant may be furnished in drums containing either
30, 50, 125 or 1750 Ibs. of refrigerant. These drums are
not returnable and they should be stored for future use if
it should ever become necessary to remove refrigerant
from the system.
If it becomes necessary to open any part of the re-
frigerant system for repairs, it will be necessary to
CHECKING THE REFRIGERANT CHARGE DURING UNIT SHUT DOWN
denser and cooler. This would be expected to be 4 hours
or more after the compressor and water pumps are stopped.
The level should be at the bottom of the upper sight glass.
Charge the refrigerant in accordance with the method
shown under REFRIGERANT CHARGING. The refriger-
ant level should be observed and the level recorded after
initial charging.
HANDLING REFRIGERANT FOR DISMANTLING AND REPAIRS
remove the charge.
TABLE 5
REFRIGERANT CHARGE YG MODELS
SHELL CODES
COOLER
CONDENSER
L
L
1125
M
M
1405
N
N
1810
P
P
1900
Q
Q
2500
R
R
3310
S
S
3550
Refrigerant charge for YB Models is 1400 lbs.
