13
COMPRESSOR TROUBLESHOOTING CHART (Continued)
2. (Continued.) D. Worn or burned out D. Check for proper oil pressure in the compressor.
bearings. Minimum required oil pressure; 15 psi engine
idling, 15 psi maximum governed engine rpm.
Check for excessive oil temperature—should not
exceed 240 degrees Fahrenheit.
E. Faulty compressor. E. Replace or repair the compressor after
determining none of the preceding installation
defects exist.
3. Excessive build-up and A. Dirty induction air filter. A. Inspect engine or compressor air filter and
recover time. Compressor replace if necessary.
should be capable of
building air system from B. Restricted induction line. B. Inspect the compressor air induction line for kinks
85-100 psi in 40 seconds and restrictions and replace as necessary.
with engine at full
governed rpm. Minimum C. Restricted discharge line C. Inspect the compressor discharge port and line
compressor performance or compressor discharge for restrictions and carbon build-up. If a carbon
is certified to meet Federal cavity. build-up is found, check for proper compressor
requirements by the cooling. Replace faulty sections of the discharge
vehicle manufacturer. Do line.
not downsize the original
equipment compressor. D. Slipping drive components. D. Check for faulty drive gears and couplings and
replace as necessary. Check the condition of
drive belts and replace or tighten, whichever is
appropriate.
E. Excessive air system E. Test for excessive system leakage and repair as
leakage. necessary. Use the following as a guide: Build
system pressure to governor cutout and allow the
pressure to stabilize for one minute. Using the
dash gauge, note the system pressure and the
pressure drop after two minutes.
The pressure drops should not exceed:
1. 2 psi in each reservoir for a single vehicle.
2. 6 psi in each reservoir for a tractor and trailer.
3. 8 psi in each reservoir for a tractor and 2
trailers.
F. Sticking unloader pistons. F. Check the operation of the unloading mechanism.
Check for proper operation of the compressor air
governor. Make certain the air connections
between the governor and compressor are
correct. Refer to figure 3. If the governor is
operating properly, replace the unloader
mechanism. Inspect for bent, linked or blocked
tubing leading to or from the governor.
G. Faulty compressor. G. Replace or repair the compressor after
determining none of the preceding installation
defects exist.
SYMPTOMS CAUSE
REMEDY