Carrier NEOS 100S - Control System Malfunctions; Air Flow Problems

62-11848 6-4
Low suction pressure
Filter-drier partially plugged 5.8
Low refrigerant charge 5.6.1
Expansion valve malfunction 6.2.10
No evaporator air flow or restricted air flow 6.2.9
Excessive frost on coil Check
Suction and discharge
pressures tend to equalize
when unit is operating
Compressor defective Replace
Hot gas solenoid malfunction 5.10
Heating:
High discharge pressure
Overcharged system 5.6.1
Condenser fan or HP2 pressure switch defective 5.9
Non-condensables in system 5.7
Condenser motor/fan defective Replace motor
Low discharge pressure
Compressor valve(s) worn or broken Replace
Hot gas two-way valve malfunction 5.10
Low suction pressure
Low refrigerant charge 5.6.1
Compressor Pressure Regulating valve mis-adjusted 5.11
Condenser Pressure Regulating valve fault 5.10
6.2.7 Abnormal Noise
Compressor
Loose mounting bolts Tighten
Worn bearings Replace
Worn or broken valves Replace
Liquid slugging 6.2.10
Insufficient oil Check
Condenser or evaporator fan
Loose shroud Check
Bearings defective Check
Fan loose on shaft Check
Bent shaft
6.2.8 Cab Command Malfunction
Cab Command non-operational
Fuse open Replace
Microprocessor malfunction Replace
Microprocessor/Cab Command cable 5.14
6.2.9 No Evaporator Air Flow or Restricted Air Flow
Evaporator coil blocked
Heavy frost on coil Check
Coil dirty 5.15
No or partial evaporator air flow
Evaporator fan loose or defective Check
Evaporator fan rotating backwards Check
Evaporator air flow blocked in box Check
Fan motor malfunction Replace
Table 6–2 Mechanical Indications
INDICATION / TROUBLE POSSIBLE CAUSES
REFERENCE
SECTION