T -304
4--1
04/08
SECTION 4
TROUBLESHOOTING
Table 4--1 General System Troubleshooting Procedures
INDICATION --
TROUBLE
POSSIBLE CAUSES
REFERENCE
SECTION
4.1 System Will Not Cool
Compressor will not run Drive--Belt loose or defective
Clutch coil defective
Clutch malfunction
Compressor malfunction
Check
Check/Replace
Check/Replace
SeeTable1--3
Electrical malfunction Coach power source defective
Circuit Breaker/safety device open
Check/Repair
Check/Reset
4.2 System Runs But Has Insufficient Cooling
Compressor Drive-Belt loose or defective
Compressor valves defective
Check
SeeTable1--3
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
4.3
4.5
4.6
5.11
5.8
Open
1.5
5.13
Restricted air flow No evaporator air flow or restriction 4.5
Heating system Heat valve stuck open 4.7
4.3 Abnormal Pressures
High discharge pressure Refrigerant overcharge
Noncondensable in system
Condenser motor failure
Condenser coil dirty
5.8.1
Check
Check
Clean
Low discharge pressure Compressor valve(s) worn or broken
Low refrigerant charge
SeeTable1--3
5.8
High suction pressure Compressor valve(s) worn or broken SeeTable1--3
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
5.11
5.8
4.6
4.5
Suction and discharge pressures
tend to equalize when system is
operating
Compressor valve defective SeeTable1--3
4.4 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
Check/Tighten
SeeTable1--3
SeeTable 1--3
4.6
1.3
Repair/Replace
Adjust/Replace
Clean
To Next Page
Loading...
