Atlas Copco XAS 185 KDU T4F HOP, Instruction Manual, Page: 52 / 62

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Problem solving
PROBLEM SOLVING CHART
Use the chart on the following pages to help solve
mechanical problems.
It is assumed that the engine is in good condition, that
there is adequate fuel flow to the filter and injection
equipment, and compressor/engine maintained with the
recommended oil.
Make sure that the wires are not damaged and that they are
clamped tight to their terminals.
ALTERNATOR PRECAUTIONS
1. Never reverse the polarity of the battery or the
alternator.
2. Never break any alternator or battery connections
while the engine is running.
3. When recharging the battery, disconnect it from the
alternator. Before using booster cables to start the
engine, be sure of the polarity and connect the batter -
ies positive to positive, negative to negative.
4. Never operate the engine without the main or voltage
sensing cables connected in the circuit.
Problem: Compressor capacity or pressure below normal.
Problem: Pressure in air receiver rises above maximum and causes safety valve to blow.
An electrical fault must be traced by an
electrician.
Possible faults Corrective actions
Air consumption exceeds capacity of compressor. Check equipment connected.
Choked air filter elements (AF). Remove and inspect elements. Clean or replace, if necessary.
Regulating valve (RV) defective. Have regulating valve removed and inspected by an Atlas copco Service representative.
Blow down valve stuck in open position. Check and correct as necessary.
Loading valve (LV) leaking past O-ring. With compressor running at maximum load speed, disconnect hose leading to unloader. If air leaks from the hose,
remove and inspect loading valve. Replace damaged or worn O-rings.
Oil separator element clogged. Have element removed and inspected by an Atlas copco Service representative.
Air intake throttle valve remains partially closed. Check unloader and identify reason for open valve; if possible: solve; else: contact Atlas copco.
Safety valve (SV) leaking. Remove and inspect. Replace if not airtight after reinstallation.
Blow-off valve leaking. Remove and inspect. Replace if necessary.
Possible faults Corrective actions
Regulating valve (RV) opens too late or its ball valve spring is broken. Have regulating valve removed and inspected by an Atlas copco Service representative.
Air leaks in regulating system. Check hoses and their fittings. Stop leaks; replace leaking hoses.
Air intake throttle valve does not close for some reason. Check unloader and identify reason for open valve; if possible: solve; else: contact Atlas copco.
Minimum pressure valve malfunctioning. Remove and inspect valve.
Blow-off valve malfunctioning. Remove and inspect valve.