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What Maintenance Does a Centrifugal Air Compressor Need?

The A–E service grade schedule for IHI turbo compressors, explained in English.

Centrifugal (turbo) air compressors are high-speed machines: impellers running on high-speed bearings inside a gearbox. Keeping them reliable is not about one big overhaul — it is about a graded preventive maintenance schedule. Following the official IHI-Sullair maintenance system, the work is divided into five grades, from daily checks to the four-year major service:

Grade A — daily  |  Grade B — every 3 months  |  Grade C — yearly  |  Grade D — every 2 years  |  Grade E — every 4 years

Grade A — Daily maintenance

• Check and record all operating parameters
• Instrument air pressure
• Oil tank vacuum
• Oil level
• Condensate drain trap operation
• Overall visual inspection of the machine
• Check for any leakage
• Check cooling water pressure / temperature

Grade B — Every 3 months (includes Grade A)

• Air intake filter: check, replace if necessary
• Oil mist separator: check, replace if necessary
• Cooler performance check
• Check related bolts for looseness, re-tighten if necessary
• Control cabinet: inspect and clean, check for loose wiring
• Re-grease the motor (see motor nameplate / manual)
• Check IGV / BOV operation

Grade C — Yearly (includes Grade B)

• Check the discharge check valve
• Replace the oil filter element
• Replace the oil mist separator element
• Check the coupling
• Check cooler performance, clean if necessary
• Check overall machine vibration
• Lubricating oil sampling and analysis, if necessary

Grade D — Every 2 years (includes Grade C)

• Replace the lubricating oil (dedicated turbo compressor oil)
• Air end inspection, cleaning and maintenance
• Impeller PT (penetrant testing) inspection
• Cooler cleaning and maintenance
• Check the blow-off silencer

Grade E — Every 4 years (includes Grade D)

• Gearbox internal inspection and maintenance
• Main oil pump inspection and maintenance
• Auxiliary oil pump inspection and maintenance
• Coupling maintenance
• Re-verify shaft alignment, surge test, etc.

Note: for official service and detailed procedures, please contact the IHI-Sullair aftermarket department or an authorized dealer. Reference: IHI-Sullair official maintenance introduction.

How Turbomax can help

Turbomax supplies alternative spare parts and service kits that cover every maintenance grade of IHI centrifugal compressors: air filter elements, oil filter elements, oil mist separators, turbo oil, couplings, cooler cleaning and replacement bundles, gearbox bearings, impellers and more — plus full overhaul support. Contact us for a fast quotation.

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