Air System
255
Possible Cause
Remedy
Problem #3: Safety valve “popping off” or exhausting air.
Check for excessive oil and compressor instal-
lation. Repair/replace/rebuild as necessary.
B. Defective check valve
Test check valve and repair/replace as necessary.
C. Defective lines between air dryer and
wet tank
Check if air reaching wet tank. Check lines
and fittings for restrictions. Repair or replace if
necessary.
A. Desiccant cartridge plugged or
saturated
Possible Cause
Remedy
Problem #4: Constant exhaust at dryer purge valve or unable to build system
pressure.
With loaded compressor, check for leakage
with soap solution. Repair or replace purge
valve.
B. Defective air governor
Test governor for proper cut-in/cut-out settings
and leakage.
C. Purge control line connected to reservoir
or exhaust port of governor
Purge control line must be connected to
unloader port of governor.
D. Purge valve frozen open; faulty heater/
thermostat wiring or blown fuse
Test heater.
A. Purge valve leaking
E. Inlet/outlet connections reversed
Reverse connections immediately.
F. Defective check valve between dryer
and wet tank
Test valve for proper operation. See Problem
#3, Remedy B.
G. Kinked or blocked discharge line
Ensure air passes through discharge line. Check
for kinds, bends, or carbon deposits.
H. Excessive bends in discharge line, al
-
lowing water to collect and freeze
Line should slope constantly from compressor
to dryer with as few bends as possible.
I. Excessive system leakage
See Problem #1.
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...