1826

Common Causes

• Oil-air pump motor failed or its overload switch tripped (codes 20/33)
• Oil-air increase or decrease detection pressure switch defective (codes 21-24, 29-32)
• Mixing valve clogged or oil-air plumbing damaged/leaking
• Contamination mixed into the oil-air lubricant

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code 20 = Spindle oil-air lubrication pump is in an overload condition; code 21 = Oil-air decrease detection pressure switch stays OFF; code 22 = Oil-air increase detection pressure switch stays OFF; code 23 = Oil-air increase detection PS turned OFF while the spindle oil-air pump is running; code 24 = Oil-air increase detection pressure switch stays ON; code 25 = Oil-air lubricant pressure signal did not turn ON within 60 seconds of the pump output turning ON; code 26 = Oil-air lubricant pressure signal turned OFF after the pump output turned ON; code 27 = Oil-air lubricant pressure signal did not turn OFF within the pump stop timer
2. 2Read the code on screen. Codes 20/33 (pump overload): reset the pump overload switch; if it trips again, inspect the oil-air lubricant for contamination and replace the pump motor.
3. 3Codes 21/32 (decrease PS stays OFF): check for a clogged mixing valve first, then replace the oil-air decrease detection pressure switch.
4. 4Codes 22/23 (increase PS stays OFF): inspect the oil-air plumbing for leaks, kinks or blockages and check pump output; replace the increase detection PS if plumbing and pump are good.
5. 5Codes 24/29 (increase PS stays ON): replace the increase detection pressure switch; if the fault persists, replace the mixing valve.
6. 6Codes 25-28/30-31 (pressure signal timing faults during pump cycle): verify the pump actually runs when its output signal turns ON, then check the lubricant pressure switch and its wiring; inspect the M SP. oil-air pump for codes 30/31.
7. 7If the alarm returns after these checks, record the alarm number, code and object and contact Okuma service.