Duty Cycle Too High - BENDIX BA-921 COMPRESSOR-STD-CLOSED ROOM Service Data Sheet

Symptom:
4.0 Oil in Supply or
Service Reservoir
(air dryer installed)
(If a maintained Bendix
PuraGuard ® system
fi lter or Bendix ®
™
PuraGuard QC oil
coalescing
fi lter is installed, call
1-800-AIR-BRAKE
(1-800-247-2725) and
speak to a Tech Team
member.)
See Table A, on page
A-3, for maintenance
schedule information.
The duty cycle is the ratio of time the compressor spends
building air to total engine running time. Air compressors
are designed to build air (to "run loaded") up to 25% of the
time. Higher duty cycles cause conditions that affect air
brake charging system performance which may require
additional maintenance. Factors that add to the duty cycle
are: air suspension, additional air accessories, use of an
undersized compressor, frequent stops, excessive leakage
from fi ttings, connections, lines, chambers or valves, etc.
A-6
What it may indicate:
Maintenance
(a) If air brake charging system mainte-
nance has not been performed.
®
That is, reservoir(s) have not been
drained per the schedule in Table
A on page A-3, Column 4 and/or
the air dryer maintenance has not
been performed as in Column 3.
(b) If the vehicle maintenance has
been performed as recommended
in Table A on page A-3, some oil in
the reservoirs is normal.
(a)
Drain all air tanks (reservoirs)
®
into the Bendix
cup.
(Bendix kit P/N 5013711).

Duty cycle too high

(c) Air brake system leakage.
(d) Compressor may be undersized for
the application.
What you should do:
Drain all air tanks and check vehicle at next
service interval using the Bendix
test. See Table A on page A-3, column 3
and 4, for recommended service sched-
ule.
Drain all air tanks into Bendix
cup (Bendix Air System Inspection Cup). If
less than one unit of reservoir contents is
found, the vehicle can be returned to ser-
vice. Note: If more than one oil unit of
water (or a cloudy emulsion mixture) is
present, change the vehicle's air dryer,
check for air system leakage (Test 2, on
page A-14), stop inspection and check
again at the next service interval.
See the BASIC
If less than one "oil unit" of water (or water/
cloudy emulsion mixture) is present, use the
BASIC
determine if the amount of oil found is within
the acceptable level.
™
BASIC test
vehicle to service. For vehicles with acces-
sories that are sensitive to small amounts
of oil, consider a Bendix
oil coalescing fi lter.
tom 4.0(c).
Also see the Table A on page A-3, column
3 for recommended air dryer cartridge
replacement schedule.
Go to Test 2 on page A-14.
See Table A, column 1, on page A-3 for
recommended compressor sizes.
the vehicle's role (for example, where a
vehicle's use has changed or service condi-
tions exceed the original vehicle or engine
OE spec's) then upgrade the compressor.
Note: The costs incurred (e.g. installing
a larger capacity compressor, etc.) are
not covered under original compressor
warranty.
vehicle, go to Symptom 4.0 (e).
™ test kit for full details.
™ cup chart on the label of the cup to
If within the normal range, return the
®
PuraGuard QC
If outside the normal range go to Symp-
If the compressor is "too small" for
If the compressor is correct for the
® ™
BASIC
® ™
BASIC test
™