1812

Common Causes

• Low oil-mist lubricant level in the unit reservoir
• Faulty turret oil-mist drip sensor switch or its wiring
• Mist lubrication unit check timer set too short, so the drip sensor cannot turn ON in time
• Defective oil-mist lubrication unit (pump/air drive) not generating mist
• Low drive air pressure or faulty pressure/flow/level switch on the M-axis mist circuit

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code 1 = Turret oil-mist drip sensor OFF for 1 s or more while mist lubrication ON signal is ON; code 2 = Turret oil-mist drip sensor stuck ON for 30 s or more; code 3 = Drip sensor input stayed OFF through two consecutive pump drive air cycles; code 4 = M-axis rotation commanded before initial dripping at power-up completed; code 5 = Pump drive air ON with lubricant level alarm/switch OFF for 24 hours; code 6 = Mist lubrication pressure alarm/switch turned OFF while mist ON signal is ON; code 7 = Turret oil-mist drip sensor OFF for 2 s or more; code 8 = Drip sensor input stuck ON through two consecutive pump drive air cycles
2. 2Read the code to identify the failed circuit: codes 1-3, 7-9, 15-16 concern the turret mist drip sensor and level; codes 10-14 concern the M-axis mist flow, pressure, level, and collect switches.
3. 3Check the oil-mist lubricant level in the reservoir and refill if low - codes 5, 9, 13, and 15 all point to a low level or a unit that ran dry for an extended time.
4. 4For code 1 or 16 (drip sensor slow to turn ON): verify mist is actually being generated; if the unit is healthy, lengthen the 'Mist Lubrication Unit Check Timer' parameter so the check window covers the sensor's normal response time.
5. 5For code 4 (M-axis rotation commanded before initial dripping finished): switch the oil-mist unit OFF and back ON to restart initial dripping. If alarm C3745 code 4 returns about two minutes later, the mist unit itself is likely defective.
6. 6Verify the drive air supply to the mist pump: pressure present, line not kinked, and the pump drive air ON signal actually actuating the unit.
7. 7If oil level, air supply, and timer are correct, test the drip sensor / flow sensor / pressure and level switches named by the code and their wiring; replace the mist lubrication unit if the sensors and supply check out.
8. 8If the alarm returns after these checks, record the alarm number and code and contact Okuma service.