Table 4-2. UNIT TROUBLESHOOTING - continued
TEST OR INSPECTION
C O R R E C T I V E ACTION
EVAPORATOR OR CONDENSER FAN MOTOR DOES NOT OPERATE.
Disconnect input power before performing internal electrical troubleshooting.
Voltages used can be deadly.
Use disconnect switch (NOT POWER CABLE) to disconnect power to unit.
Damage to cable connector pins will result if cable is used.
Step 1. Using wiring diagram (figure 4-6), check electrical connectors and individual wires for tightness
Tighten, repair, or replace as indicated.
Step 2. Check operation of motor controller.
Step 3. Check operation of fan motor.
Test motor. (See paragraph 4-43 or 4-46.) Notify supervisor if motor is defective.
Step 4. Check operation of MODE selector rotary switch.
EXCESSIVELY NOISY OPERATION.
A knocking or hammering noise is usually caused by liquid refrigerant in the
compressor. This can seriously damage or destroy the compressor.
Be sure unit has been connected to input power at least four hours prior to
Step 1. Check fans for looseness or damage, and for rotational clearance.
Tighten loose fans, adjust for rotational clearance, or replace fans. (See paragraph 4-43
Step 2. Check all internal components for looseness, vibration, and security.
Tighten, adjust, and secure as necessary.