Refrigerant Charge - Carrier WeatherMaster Puron 48HC D17 Service And Maintenance Instructions

Refrigerant Charge

Unit panels must be in place when unit is operating during the
charging procedure. To prepare the unit for charge adjustment,
use the following instructions.
NO CHARGE
Use standard evacuating techniques. Evacuate system down to
500 microns and let set for 10 minutes to determine if system
has a refrigerant leak. If evacuation level raises to
1100 microns and stabilizes, the system has moisture in it and
should be dehydrated per GTAC2-5 recommends.
If system continues to rise above 1100 microns, the system has
a leak and should be pressurized and leak tested using appro-
priate techniques as explained in GTAC2-5. After evacuating
system, weigh in the specified amount of refrigerant as listed
on the unit rating plate.
LOW-CHARGE COOLING
Using Cooling Charging Charts (Fig. 22-25), vary refrigerant
until the conditions of the appropriate chart are met. Note the
charging charts are different from the type normally used.
Charts are based on charging the units to the correct superheat
for the various operating conditions. Accurate pressure gage
and temperature sensing devices are required. Connect the
pressure gage to the service port on the suction line. Mount the
temperature sensing device on the suction line and insulate it
so that outdoor ambient temperature does not affect the read-
ing. Indoor-air cfm must be within the normal operating range
of the unit.
48HC SIZE DESIGNATION
17
20
24
28
NOMINAL TON
REFERENCE
15
17.5
20
25
17
EXAMPLE:
Model 48HC*D28
Circuit A
Outdoor Temperature . . . . . . . . . . . . . . . . . . . . . . 85°F (29°C)
Suction Pressure . . . . . . . . . . . . . . . . . . . . . 125 psig (862 kPa)
Suction Temperature should be . . . . . . . . . . . . . . . 63°F (17°C)
Circuit B
Outdoor Temperature . . . . . . . . . . . . . . . . . . . . . . 85°F (29°C)
Suction Pressure . . . . . . . . . . . . . . . . . . . . . 120 psig (827 kPa)
Suction Temperature should be . . . . . . . . . . . . . . . 58°F (14°C)
USING THE COOLING CHARGING CHARTS
Take the outdoor ambient temperature and read the suction pres-
sure gage. Refer to chart to determine what suction temperature
should be. If suction temperature is high, add refrigerant.
If suction temperature is low, carefully recover some of the
charge. Recheck the suction pressure as charge is adjusted.
Select the appropriate unit charging chart from Fig. 22-25.
Take the outdoor ambient temperature and read the suction
pressure gage. Refer to chart to determine what suction tem-
perature should be. If suction temperature is high, add refriger-
ant. If suction temperature is low, carefully recover some of the
charge. Recheck the suction pressure as charge is adjusted.
For sizes 17-28, perform this procedure once for Circuit A and
once for Circuit B.