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INDICATION/
TROUBLE
3.1
System Will Not Cool
Compressor will not run
Electrical malfunction
3.2
System Runs But Has Insufficient Cooling
Compressor
Refrigeration system
Restricted air flow
Heating system
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
3.4
Abnormal Noise Or Vibrations
Compressor
05/09
SECTION 3
TROUBLESHOOTING
Table 3-1 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
No evaporator air flow or restriction
Heat valve stuck open
Refrigerant overcharge
Noncondensable in system
Condenser motor failure
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
POSSIBLE CAUSES
3--1
REFERENCE
SECTION
Check
Check/Replace
Check/Replace
See Table 1--2
Check/Repair
Check/Reset
Check
See Table 1--2
3.3
3.6
3.7
4.11
4.7
Open
1.9
Check
3.6
3.8
4.7.1
Check
Check
Clean
See Table 1--2
4.7
See Table 1--2
Open
Check/Open
4.11
4.7
3.7
3.6
See Table 1--2
Check/Tighten
See Table 1--2
See Table 1--2
3.7
4.15.3
Check
Check/Adjust
Clean
T-336
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