BENDIX AD-IP INTEGRAL PURGE AIR DRYER Manual page 26

COMPLAINTS COMMON TO THE CHARGING & AIR SUPPLY SYSTEM
Complaint: Can Not Build System Pressure
• Discharge line plugged or restricted: see Common Test 1.
• Air pressure trapped between governor and compressor
unloaders: see Common Test 2.
• Blow leakage at air dryer exhaust: see Common Test 3.
Complaint: Air System Builds Too Slow
• Discharge line restricted: see Common Test 1.
• Discharge line leakage: see Common Test 5.
• Air leaking at air dryer exhaust: see Common Test 3.
• Compressor head gasket failure: apply soap solution
around cylinder head. If leakage between head and block
noted repair or replace compressor.
• Air pressure trapped between governor and compressor
unloaders: see Common Test 2.
• Air system leakage: see Common Test 4.
Complaint: Can Not Build System Pressure Above "X" psi.
• Blow leakage at compressor unloaders: remove all
hardware from compressor inlet then remove governor.
With 120 psi shop air applied to compressor unloader port
listen for leakage at inlet. If noted, repair leak or replace
compressor.
• Incorrect setting on governor: verify safety valve operation.
Drain air from system, remove or disconnect governor from
compressor and install gauge in governor unloader (UNL)
port. Build system pressure and note when pressure on
dash gauge and test gauge are equal. Should be equal at
maximum setting of governor.
• Discharge line leakage: see Common Test 5.
• Air system leakage: see Common Test 4.
• Compressor head gasket failure: apply soap solution
around cylinder head. If leakage between head and block
noted repair or replace compressor.
Complaint: Air Dryer Cycles "ON & OFF" Constantly
This complaint caused by leakage, either service system or
supply system. Service system leakage is shown on dash
gauges supply system leakage is not. Note: System purge air
dryers will purge more often than those with integral purge
volume.
Service system leakage: see Common Test 4.
Supply system component leakage: drain system, install
gauge and shop air hose in place of drain cock in supply
reservoir. Fill system to 120 psi, shut off shop air and check
leakage on following components in order presented:
• Compressor unloader leakage.
• Drain system, remove governor from compressor plug
governor UNL port and re-test. If leakage OK repair
compressor unloader mechanism or replace compressor.
If leakage NOT OK then next.
• Holset ECON valve (used with Holset Type "E & QE" comp.)
missing, malfunctioning, leaking.
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• Is ECON valve required but missing? If YES, install, along
with special Holset check valve w/choke. If NO and ECON
valve present replace ECON valve and special check valve.
If NO and ECON not required then next.
• Air dryer leakage: Remove line from air dryer inlet and with
120 psi in supply res. soap exhaust and inlet port of air
dryer. If leakage greater than 1" bubble in 1 second at
exhaust port, repair or replace check valve (on dryers with
integral purge volume) or replace body assy. on system
purge air dryers. If leakage greater than 1" bubble in 1
second at inlet port, repair or replace purge valve assy. (on
dryers with integral purge volume) or replace turbo cut-off
valve on system purge air dryers.
Complaint: System Pressure Goes to 150+ psi
• Drain air system to 0 psi, remove/disconnect governor from
compressor. Start engine and note air pressure rise on
dash gauges. Apply 120 psi shop air to compressor
unloader port. If air pressure continues to rise, repair
compressor unloaders or replace compressor. If air ceases
to rise, repair or replace governor.
Complaint: Low Pressure Warning After Only 1 or 2
Applications
• Brakes out of adjustment: adjust brakes.
• Excessive system leakage on service (application) side of
system: Build system pressure to 120 psi and shut off
engine. With park brakes released, make full service
application and note dash gauges for 2 minutes. Pressure
drop on either gauge should not exceed 4 psi. (2 psi per
min.) If pressure drop excessive, find leakage in service
system, if OK, then next.
• Incorrect low pressure switch in use or setting incorrect:
Build system to 120 psi. Engine OFF ignition ON, slowly
drain air pressure from one service reservoir. Low pressure
warning on at minimum 60 psi, maximum 10-15 psi less
than governor cut-in pressure.