3--1
© 2015 Mobile Climate Control
T-367 Rev. 05/2015
SECTION 3
TROUBLESHOOTING
Table 3-1 General System Troubleshooting Procedures
INDICATION -
TROUBLE
POSSIBLE CAUSES
3.1 System Will Not Cool
Compressor will not run Drive-Belt loose or defective
Clutch coil defective
Clutch malfunction
Compressor malfunction
Electrical malfunction Coach power source defective
Circuit Breaker/safety device open
3.2 System Runs But Has Insufficient Cooling
Compressor Drive-Belt loose or defective
Compressor valves defective
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
Restricted air flow No evaporator air flow or restriction
Heating system Heat valve stuck open
3.3 Abnormal Pressures
High discharge pressure Refrigerant overcharge
Noncondensable in system
Condenser motor failure
Condenser coil dirty
Low discharge pressure Compressorvalve(s)wornorbroken
Low refrigerant charge
High suction pressure Compressorvalve(s)wornorbroken
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
Suction and discharge pressures tend
to equalize when system is operating
Compressor valve defective
3.4 Abnormal Noise Or Vibrations
Compressor Loose mounting hardware
Worn bearings
Worn or broken valves
Liquid slugging
Insufficient oil
Clutch loose, rubbing or is defective
Drive-Belt cracked, worn or loose
Dirt or debris on fan blades
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