System Will Not Cool; System Runs But Has Insfficient Cooling; Abnormal Pressures; Abnormal Noises Or Vibrations - Carrier 68G5-105 Series Operation & Service Manual

INDICATION/
TROUBLE

3.3.1 System Will Not Cool

Compressor will not run
Electrical malfunction

3.3.2 System Runs But Has Insfficient Cooling

Compressor
Refrigeration system

3.3.3 Abnormal Pressures

High discharge pressure
Low discharge pressure
High suction pressure
Low suction pressure
Suction and discharge pressures
tend to equalize when system is
operating

3.3.4 Abnormal Noises Or Vibrations

Compressor
Condenser or evaporator fans
Table 3-5. General System Troubleshooting Procedures
V-Belt loose or defective
Clutch coil defective
Clutch malfunction
Compressor malfunction
Coach power source defective
Circuit Breaker/safety device open
V-Belt loose or defective
Compressor valves defective
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
Refrigerant overcharge
Noncondensable in system
Condenser fan rotation incorrect
Condenser coil dirty
Compressor valve(s) worn or broken
Low refrigerant charge
Compressor valve(s) worn or broken
Suction service valve partially closed
Filter-drier inlet valve partially closed
Filter-drier partially plugged
Low refrigerant charge
Expansion valve malfunction
Restricted air flow
Compressor valve defective
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
Loose mounting hardware
Defective bearings
Blade interference
Blade missing or broken
POSSIBLE CAUSES
3-5
REFERENCE
SECTION
Check
Check/Replace
Check/Replace
See Note.
Check/Repair
Check/Reset
Check
See Note.
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
4.4
4.8
Check
Clean
See Note.
4.5 and 4.7
See Note.
Open
Check/ Open
4.10
4.5 and 4.7
3.3.7
3.3.6
See Note.
Check/Tighten
See Note.
See Note.
3.3.7
4.12.4
Check
Check/Adjust
Clean
Check/Tighten
Replace
Check
Check/Replace
T-312