Checking And Adjusting Refrigerant Charge; Electrical Controls And Wiring; Refrigerant Circuit; Evaporator Airflow - Carrier 50SD Install And Operation Instructions

2. Turn motor/grille assembly upside down on top cover to
expose the fan blade.
3. Inspect the fan blades for cracks or bends.
4. If fan needs to be removed, loosen the setscrew and slide the
fan off the motor shaft.
5. When replacing fan blade, position blade so that the hub is 1/8
in. away from the motor end (1/8 in. of motor shaft will be
visible).
6. Ensure that setscrew engages the flat area on the motor shaft
when tightening
7. Replace grille.

ELECTRICAL CONTROLS AND WIRING

Inspect and check the electrical controls and wiring annually. Be
sure to turn off the electrical power to the unit and install lockout
tag.
Remove access panel to locate all the electrical controls and
wiring. Check all electrical connections for tightness. Tighten all
screw connections. If any smoky or burned connections are
noticed, disassemble the connection, clean all the parts, restrip the
wire end and reassemble the connection properly and securely.
After inspecting the electrical controls and wiring, replace the
access panel. Start the unit, and observe at least one complete
heating cycle and one complete cooling cycle to ensure proper
operation. If discrepancies are observed in either or both operating
cycles, or if a suspected malfunction has occurred, check each
electrical component with the proper electrical instrumentation.
Refer to the unit wiring label when making these checkouts.
NOTE: Refer to the heating and/or cooling sequence of operation
in this publication as an aid in determining proper control
operation

REFRIGERANT CIRCUIT

Inspect all refrigerant tubing connections and the unit base for oil
accumulations annually. Detecting oil generally indicates a refrig-
erant leak.
EXPLOSION, PERSONAL INJURY HAZARD
Failuire to follow this warning could result in personal injury,
death, or property damage.
System under pressure. Relieve pressure and recover all
refrigerant before system repair or final unit disposal. Use all
service ports and open all flow-control devices, including
solenoid valves.
If oil is detected or if low cooling performance is suspected,
leak-test all refrigerant tubing using an electronic leak-detector,
halide torch, or liquid-soap solution. If a refrigerant leak is
detected, refer to Check for Refrigerant Leaks section.
If no refrigerant leaks are found and low cooling performance is
suspected, refer to Checking and Adjusting Refrigerant Charge
section.

EVAPORATOR AIRFLOW

The heating and/or cooling air-flow does not require checking
unless improper performance is suspected. If a problem exists, be
sure that all supply- and return-air grilles are open and free from
obstructions, and that the air filter is clean. When necessary, refer
to Indoor Airflow and Airflow Adjustments section to check the
system airflow.
METERING DEVICE — ACCURATER PISTON
This metering device is a fixed orifice and is contained in a brass
body in the liquid line feeding the indoor coil.

TROUBLESHOOTING

Use the Troubleshooting–Cooling guide (see Table 6) if problems
occur with these units.

START-UP CHECKLIST

Use the Start-Up checklist to ensure proper start-up procedures are
followed.
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