Condition Possible faults Suggested remedy 11.    High oil consumption a.    Oil level too high a.    Do not overfill crankcase Keep level within lower half of sight glass b.    Breather valve malfunctioning b.    Check valve c.    Piston ring(s) worn or broken c.    Have condition oft piston rings checked d.    Intake filter clogged d.    Clean or replace 12.    Loading periods too long a.    Excessive air consumption a.    Decrease consumption b.    Compressor not in optimum condition b.    Have compressor inspected c.    Sticking or damaged valves c.    Clean or replace 13.    Thermal overload relay cuts Overload relay incorrectly set Check and adjust to correct setting Reset relay out during starting 14.    Thermal overload relay cuts a.    Overload relay incorrectly set a.    See 13 out during operation b.    One phase of mains supply line interrupted b.    Check fuses and line terminals tightness Check voltage across motor line terminals c.    Mains supply voltage variations exceed c.    Consult power supplier normal tolerances d.    Ambient temperature too high and causes d.    Improve ventilation of room overload relay to trip e.    Motor stops and starts too frequently e.    See 10 On units with motor starter, change to half-automatic operation f. Overcurrent due to motor-failure of com- f. Measure motor line current in the three phases If currents pressor exceed rated motor current, have compressor inspected, if cur- rents are not equal, have motor inspected 15.    L P relief valve blows a.    Defective valve in H P cylinder head a.    Inspect and replace parts as necessary b.    Defective relief valve b.    Replace valve In case of motor failure.  return to local authorized motor repair station. 6 Valve replacement procedure Warning:  Release  the  pressure  from  the  air  receiver  and compressor before starting repair works Always switch off the current. Valves A   faulty   valve   must   be   attended   to   immediately.      Serious damage can result if a compressor Is operated with a broken valve disc.  The instructions given must be faithfully followed when inspecting or replacing the valve discs. Removal and assembly (See Drawings E and F) Cylinder(s) L5/11 LT12 Operation sequence LT5/11- LT5/11- low- high- pressure pressure Remove the fan guard and the cover of the air intake silencer. Disconnect  cylinder  head  cover  (11) from  the  in-  and  outlet  pipe  flanges Remove cover (11). Remove    cylinder    head    cover    (11) Disconnect  outlet  cap  (15)  from  the temperature   reducer   and   inlet   cap (14)  from  the  pulsation  damper  and the air intake silencer Remove outlet and inlet caps (15 and 14). 8