8
3. Slide filters out of unit.
4. Clean coil using a commercial coil cleaner or dish-
washer detergent in a pressurized spray canister. Wash
both sides of coil and flush with clean water. For best
results, back--flush toward return--air section to re-
move foreign material. Flush condensate pan after
completion.
5. Reinstall economizer and filters.
6. Reconnect wiring.
7. Replace access panels.
Evaporator Coil Metering Devices
The metering devices are multiple fixed--bore devices
(Acutrol
t
) swedged into the horizontal outlet tubes from
the liquid header, located at the entrance to each
evaporator coil circuit path. These are non--adjustable.
Service requires replacing the entire liquid header
assembly.
To check for possible blockage of one or more of these
metering devices, disconnect the supply fan contactor
(IFC) coil, then start the compressor and observe the
frosting pattern on the face of the evaporator coil. A frost
pattern should develop uniformly across the face of the
coil starting at each horizontal header tube. Failure to
develop frost at an outlet tube can indicate a plugged or a
missing orifice.
Refrigerant System Pressure Access Ports
There are two access ports in the system -- on the suction
tube near the compressor and on the discharge tube near
the compressor. These are brass fittings with black plastic
caps. The hose connection fittings are standard 1/4 SAE
male flare couplings.
The brass fittings are two--piece High Flow valves, with a
receptacle base brazed to the tubing and an integral
spring--closed check valve core screwed into the base.
(See Fig. 11.) This check valve is permanently assembled
into this core body and cannot be serviced separately;
replace the entire core body if necessary. Service tools are
available from RCD that allow the replacement of the
check valve core without having to recover the entire
system refrigerant charge. Apply compressor refrigerant
oil to the check valve core’s bottom o--ring. Install the
fitting body with 96 +/ --10 in--lbs of torque; do not
overtighten.
PURON
R
(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 cylinders.
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 position (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 recommended that refrigerant always be removed
from the cylinder as a liquid. Admit liquid refrigerant into
the system in the discharge line. If adding refrigerant into
the suction line, use a commercial metering/expansion
device at the gauge manifold; remove liquid from the
cylinder, pass it through the metering device at the gauge
set and then pass it into the suction line as a vapor. Do not
remove Puron (R--410A) refrigerant from the cylinder as a
vapor.
Refrigerant Charge
Amount of refrigerant charge is listed on the unit’s
nameplate. Refer to Carrier GTAC2--5 Charging,
Recovery, Recycling and Reclamation training manual
and the following procedures.
Unit panels must be in place when unit is operating during
the charging procedure.
No Charge
Use standard evacuating techniques. After evacuating
system, weigh in the specified amount of refrigerant.
Low--Charge Cooling
Using Cooling Charging Charts, Figs. 13--15, vary
refrigerant until the conditions of the appropriate chart are
met. Note the charging charts are different from type
normally used. Charts are based on charging the units to
the correct subcooling for the various operating
conditions. Accurate pressure gauge and temperature
sensing device are required. Connect the pressure gauge to
the service port on the liquid line. Mount the temperature
sensing device on the liquid line 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
Take the outdoor ambient temperature and read the liquid
pressure gauge. Refer to chart to determine what liquid
temperature should be. If liquid temperature is low, add
refrigerant. If liquid temperature is high, carefully recover
some of the charge. Recheck the liquid pressure as charge
is adjusted.
48L
C
Summary of Contents for 48LC 05
Page 10: ...10 COOLING CHARGING CHARTS C14037 Fig 13 Cooling Charging Charts 3 Ton 48LC ...
Page 11: ...11 COOLING CHARGING CHARTS cont C14038 Fig 14 Cooling Charging Charts 4 Ton 48LC ...
Page 12: ...12 COOLING CHARGING CHARTS cont C14039 Fig 15 Cooling Charging Charts 5 Ton 48LC ...
Page 35: ...35 WIRING DIAGRAMS C14043 Fig 44 Unit Wiring Diagram Power 208 230V 460V 3 Phase 48LC ...
Page 36: ...36 C14044 Fig 45 Unit Wiring Diagram Power 575V 3 Phase 48LC ...
Page 37: ...37 C14045 Fig 46 Unit Wiring Diagram Control 48LC ...
Page 47: ...47 48LC ...