Carrier 50TCA04-A07 - Manual (Page 7)

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6. Hold garden sprayer nozzle close to finned areas and
apply cleaner with a vertical, up--and--down motion.
Avoid spraying in horizontal pattern to minimize po-
tential for fin damage.
7. Ensure cleaner thoroughly penetrates deep into finned
areas.
8. Interior and exterior finned areas must be thoroughly
cleaned.
9. Finned surfaces should remain wet with cleaning
solution for 10 minutes.
10. Ensure surfaces are not allowed to dry before rinsing.
Reapplying cleaner as needed to ensure 10--minute
saturation is achieved.
11. Thoroughly rinse all surfaces with low velocity clean
water using downward rinsing motion of water spray
nozzle. Protect fins from damage from the spray
nozzle.
Evaporator Coil
Cleaning the Evaporator Coil
1. Turn unit power off. Install lockout tag. Remove
evaporator coil access panel.
2. If economizer or two--position damper is installed, re-
move economizer by disconnecting Molex plug and
removing mounting screws.
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
(Acutrolt) wedged 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.
PURONR (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) 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) 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) 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, Fig. 12, 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
superheat for the various operating conditions. Accurate
pressure gauge and temperature sensing device are
required. Connect the pressure gauge 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 reading. Indoor--air cfm
must be within the normal operating range of the unit.
50TC