Hitachi DSP Series Error Code H002

Hitachi Compressor Major Oil

Model: DSP Series | Code: H002

Applicable Systems
WJ200

Symptoms

Oil pressure in the lubrication circuit is below 2.0 bar (29 psi) during loaded operation. The low oil pressure switch triggers a compressor shutdown to prevent airend bearing damage.

Possible Causes

  • Low oil level in the sump from leaks, separator carryover, or inadequate initial fill
  • Oil pump drive coupling broken or oil pump internal wear reducing output pressure
  • Oil filter severely clogged, creating excessive suction head and starving the pump
  • Low oil pressure switch out of calibration or failed closed

Troubleshooting Steps

  1. Step 1: Check the oil sight glass with the compressor stopped - oil must be at the center mark
    Top up with Hitachi HISYN FLUID O-200 if low. Inspect all fittings, drain plugs, and the separator for leaks
  2. Step 2: Remove the oil pump cover and inspect the drive coupling between the airend and pump shaft
    Replace the coupling if cracked. Rotate the pump by hand - it should turn smoothly without binding
  3. Step 3: Replace the oil filter element and inspect the old element for metal particles or sludge
    If metal is present, take an oil sample for analysis and inspect airend bearings
  4. Step 4: Remove the oil pressure switch and connect a calibrated gauge to the same port
    Run the compressor and compare actual pressure to the switch setting. Replace the switch if actual pressure is >2.5 bar but alarm still trips

How to Reset

Reset: Correct the oil level or repair the pump, then press Reset on the controller. The alarm clears after a 30-second loaded run with oil pressure confirmed above 2.5 bar.

Common Replacement Parts

  • HIT-3010: Oil pump assembly, DSP 37-55 (External gear pump, 10 cc/rev)
  • HIT-3011: Oil pump coupling spider (Polyurethane, jaw-type, 28 mm hub)
  • HIT-3012: Oil filter element, DSP (Spin-on, M24x1.5, 100 mm height)
  • HIT-3013: Low oil pressure switch (Adjustable 1.5-3.5 bar, G1/4)

Frequently Asked Questions

  • Q: What oil does Hitachi recommend?

    HISYN FLUID O-200 (ISO VG 46 synthetic) for DSP series. For food-grade applications, use HISYN FLUID FG-46.

  • Q: How much oil does a DSP 45 hold?

    Approximately 28 liters. Fill to the center of the sight glass with the compressor stopped and level.

Related Hitachi Fault Codes

Source: Hitachi DSP Series Operation and Maintenance Manual, HIT-DSP-OM-01

Category: Compressor