Carrier 68G5-105 Series - General System Troubleshooting Procedures; 3.3.1 System Will Not Cool; 3.3.2 System Runs But Has Insufficient Cooling; 3.3.3 Abnormal Pressures

3-5 T -312
Table 3-5. General System Troubleshooting Procedures
INDICATION/
TROUBLE
POSSIBLE CAUSES
REFERENCE
SECTION
3.3.1 System Will Not Cool
Compressor will not run V-Belt loose or defective
Clutch coil defective
Clutch malfunction
Compressor malfunction
Check
Check/Replace
Check/Replace
See Note.
Electrical malfunction Coach power source defective
Circuit Breaker/safety device open
Check/Repair
Check/Reset
3.3.2 System Runs But Has Insfficient Cooling
Compressor V-Belt loose or defective
Compressor valves defective
Check
See Note.
Refrigeration system Abnormal pressures
No or restricted evaporator air flow
Expansion valve malfunction
Restricted refrigerant flow
Low refrigerant charge
Service valves partially closed
Safety device open
Liquid solenoid valve stuck closed
3.3.3
3.3.6
3.3.7 and 4.11
3.3.7 and 4.11
4.5 and 4.7
Open
1.6
Check
3.3.3 Abnormal Pressures
High discharge pressure Refrigerant overcharge
Noncondensable in system
Condenser fan rotation incorrect
Condenser coil dirty
4.4
4.8
Check
Clean
Low discharge pressure Compressor valve(s) worn or broken
Low refrigerant charge
See Note.
4.5 and 4.7
High suction pressure Compressor valve(s) worn or broken See Note.
Low suction pressure Suction service valve partially closed
Filter-drier inlet valve partially closed
Filter-drier partially plugged
Low refrigerant charge
Expansion valve malfunction
Restricted air flow
Open
Check/ Open
4.10
4.5 and 4.7
3.3.7
3.3.6
Suction and discharge pressures
tend to equalize when system is
operating
Compressor valve defective See Note.
3.3.4 Abnormal Noises Or Vibrations
Compressor Loose mounting hardware
Worn bearings
Worn or broken valves
Liquid slugging
Insufficient oil
Clutch loose, rubbing or is defective
V-belt cracked, worn or loose
Dirt or debris on fan blades
Check/Tighten
See Note.
See Note.
3.3.7
4.12.4
Check
Check/Adjust
Clean
Condenser or evaporator fans Loose mounting hardware
Defective bearings
Blade interference
Blade missing or broken
Check/Tighten
Replace
Check
Check/Replace