Puron® (R-410A) Refrigerant; Refrigerant Charge - Carrier WeatherExpert 48LC 14 Series Service And Maintenance Instructions

PROBLEM
Suction Pressure Too Low
Evaporator Fan Will Not Shut Off
Compressor Makes Excessive Noise
PURON (R-410A) REFRIGERANT
®
This unit is designed for use with Puron (R-410A) refrigerant. Do
not use any other refrigerant in this system.
Puron (R-410A) refrigerant is provided in pink (rose) colored cyl-
inders. These cylinders are available with and without dip tubes;
cylinders with dip tubes will have a label indicating this feature.
For a cylinder with a dip tube, place the cylinder in the upright po-
sition (access valve at the top) when removing liquid refrigerant
for charging. For a cylinder without a dip tube, invert the cylinder
(access valve on the bottom) when removing liquid refrigerant.
Because Puron (R-410A) refrigerant is a blend, it is strongly rec-
ommended that refrigerant always be removed from the cylinder
as a liquid. Admit liquid refrigerant into the system in the dis-
charge line. If adding refrigerant into the suction line, use a com-
mercial metering/expansion device at the gage manifold; remove
liquid from the cylinder, pass it through the metering device at the
gage set and then pass it into the suction line as a vapor. Do not re-
move Puron (R-410A) refrigerant from the cylinder as a vapor.

Refrigerant Charge

Amount of refrigerant charge is listed on the unit's nameplate. Re-
fer to Carrier GTAC2-5 Charging, Recovery, Recycling and Rec-
lamation training manual and the following procedures.
Unit panels must be in place when unit is operating during the
charging procedure to prepare the unit for charge adjustment.
Table 1 — Cooling Service Analysis (cont)
CAUSE
Dirty air filter.
Low refrigerant charge.
Metering device or low side restricted.
Insufficient evaporator airflow.
Temperature too low in conditioned area.
Outdoor ambient below 25°F.
Time off delay not finished.
Compressor rotating in wrong direction.
8
Replace filter.
Check for leaks; repair and recharge.
Remove source of restriction.
Increase air quantity. Check filter and replace if
necessary.
Reset thermostat.
Install low-ambient kit.
Wait for 30-second off delay.
Reverse the 3-phase power leads.
NO CHARGE
Use standard evacuating techniques. After evacuating system,
weigh in the specified amount of refrigerant.
LOW-CHARGE COOLING
Using Cooling Charging Charts (Fig. 9-13), 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 subcooling for the various op-
erating conditions. Accurate pressure gage and temperature sens-
ing device are required. Connect the pressure gage to the service
port on the discharge line. Mount the temperature sensing device
on the liquid line leaving the condenser coil and insulate it so that
outdoor ambient temperature does not affect the reading. Indoor-
air cfm must be within the normal operating range of the unit.
TO USE COOLING CHARGING CHARTS
Select the appropriate unit charging chart from Fig. 9-13. Take the
liquid-line temperature and read the discharge pressure gage. Re-
fer to chart to determine what liquid-line temperature should be. If
liquid-line temperature is high, add refrigerant. If liquid-line tem-
perature is low, carefully recover some of the charge. Recheck the
discharge pressure as charge is adjusted.
EXAMPLE:
Model 48LC**17
Liquid-Line Temperature . . . . . . . . . . . . . . . . . . . . . . 85°F (29°C)
Discharge Pressure. . . . . . . . . . . . . . . . . . . . . 350 psig (2413 kPa)
REMEDY