BENDIX TCH-001-045 Manuel D’Utilisation
• Increase system maintenance through more frequent reservoir draining, dryer cartridge change out, and
discharge line replacement.
Optimizing systems in Steps 4, 5, 6, and 7 may also help if the duty cycle cannot be reduced.
If the duty cycle does not exceed 25% proceed to step 4.
Step 4: Compressor Inlet Air Supply System
Check for damaged, defective or dirty air filter on engine or compressor. Check for leaking, damaged or defective
compressor air intake components (i.e. induction line, fittings, gaskets, filter bodies, etc.). Damaged or leaking
lines as well as dirty filters result in unfiltered intake air being supplied to the compressor. Operating the
compressor with unfiltered intake air results in excessive wear to the upper piston rings and cylinder bores in a
relatively short time. If any one of these conditions is found make all necessary repairs and/or filter replacement.
Once the compressor is damaged in such a manner the compressor must be replaced.
The maximum allowable air inlet restriction (vacuum) is 25 inches (6.2kPa) of water. Exceeding this limit will
cause air along with oil to be drawn from the compressor crankcase into the delivery air. If high inlet vacuum
exists, check compressor air inlet line for kinks, excessive bends or other restrictions. (The compressor intake
should not be connected to any part of the exhaust gas recirculation (E.G.R.) system on the engine. Reconfigure
the inlet to remove this connection if present). Perform necessary repair or replacement to damaged or
malfunctioning components and place vehicle back into service.
If inlet air is clean and free of restriction proceed to Step 5.
Step 5: Compressor Coolant Supply System
Coolant temperature at the water outlet port of the compressor must not exceed 220
°F (104°C). Temperatures
beyond this level result in high cylinder temperatures. The results of high temperatures are:
• Cylinder bore distortion-causing oil to pass by the rings.
• Cylinder bore distortion-causing oil to pass by the rings.
• Breakdown of lubrication between piston ring and bore causing premature wear.
• Breakdown of oil causing carbon formation.
• High dryer inlet temperatures causing a loss of drying efficiency.
Indicators of insufficient cooling include:
• Heavy carbon deposits in the cylinder head, discharge line or fittings.
Indicators of insufficient cooling include:
• Heavy carbon deposits in the cylinder head, discharge line or fittings.
• Carbonized oil deposits in the inlet cavity.
• Discoloration of the compressor cylinders or cylinder head.
If any one of the above indicators is present, measure coolant temperature under normal operating conditions. If
coolant temperature is above recommendations inspect the coolant lines and fittings for accumulated rust scale,
kinks and restrictions. Remove accumulated grease, grime or dirt from the cooling fins. Optimum cooling is
achieved when engine coolant flows into the compressor at one end and out at the opposite end with the inlet at
the lowest port (recommended coolant flow is 0.5 gpm at idle and a minimum of 2.5 gpm at max rpm). If these
actions do not succeed in reducing the coolant temperature, consult the engine manufacturer for determination of
additional methods to reduce the coolant temperature.
If the compressor operated under these conditions replace the compressor.
If coolant temperature is at or below recommendations proceed to Step 6.
Step 6: Compressor Oil Supply and Return System
Check the engine oil pressure with a test gauge and compare the reading to the engine specifications. Higher than
specified pressure can result in an excessive amount of oil in the compressor crankcase which will increase the
likelihood of oil on the cylinder walls and opportunity to migrate past the piston rings. (Bendix does not
recommend restricting the compressor oil supply line because of the possibility of plugging the restriction with oil
If any one of the above indicators is present, measure coolant temperature under normal operating conditions. If
coolant temperature is above recommendations inspect the coolant lines and fittings for accumulated rust scale,
kinks and restrictions. Remove accumulated grease, grime or dirt from the cooling fins. Optimum cooling is
achieved when engine coolant flows into the compressor at one end and out at the opposite end with the inlet at
the lowest port (recommended coolant flow is 0.5 gpm at idle and a minimum of 2.5 gpm at max rpm). If these
actions do not succeed in reducing the coolant temperature, consult the engine manufacturer for determination of
additional methods to reduce the coolant temperature.
If the compressor operated under these conditions replace the compressor.
If coolant temperature is at or below recommendations proceed to Step 6.
Step 6: Compressor Oil Supply and Return System
Check the engine oil pressure with a test gauge and compare the reading to the engine specifications. Higher than
specified pressure can result in an excessive amount of oil in the compressor crankcase which will increase the
likelihood of oil on the cylinder walls and opportunity to migrate past the piston rings. (Bendix does not
recommend restricting the compressor oil supply line because of the possibility of plugging the restriction with oil