Replacement Cycle & Practical Guide for Air Compressor “Three Filters + One Oil”

CHANUN  Air Compressor

Regularly replacing the “three filters + one oil” is like giving your air compressor a heart health check.

In daily maintenance, the “three filters + one oil” are essential. They act as the compressor’s immune system, safeguarding stable operation. When should these key components be replaced? And how should you do it correctly? This article gives you a clear, practical explanation.

01

What Are the “Three Filters + One Oil”?

The “three filters + one oil” include the air filter, oil filter, oil separator, and screw compressor oil.

• The air filter removes dust and particles from intake air, preventing contaminants from entering the compression system.

• The oil filter traps metal particles and impurities in the lubricant to keep the oil clean.

• The oil separator separates compressed air from the lubricant, ensuring clean, oil-free discharge air.

• Screw compressor oil not only lubricates moving parts but also seals, cools, and prevents rust.

Together, they form the compressor’s protection system. Failure in any one of them can trigger a chain reaction and affect overall performance.

02

Replacement Cycle: Varies by Machine & Environment

A new machine requires its first maintenance at 500 hours, replacing the compressor oil and oil filter.

Standard replacement intervals:

• Air Filter: Every 1500–2000 hours.
  In dusty environments (mining, ceramics, textile mills), shorten to 500 hours or less.

• Oil Filter: First replacement at 500 hours, then every 2000–3000 hours.

• Oil Separator: Typically lasts about 3000 hours, or replace immediately if pressure drop exceeds 0.12 MPa.

• Screw Compressor Oil: First change at 500 hours, then every 4000 hours or once a year if annual operating hours are below 4000.

Environmental factors significantly affect intervals.
High temperature, high humidity, or dusty conditions may require shortening intervals by 30%–50%.
If the machine starts and stops frequently (over 10 times/day), reduce the oil replacement cycle by 20%–30%.

03

Replacement Procedures: Safety First, Step by Step

Start with proper safety preparation. Cut off the power and lock out the switch. Ensure the system is fully depressurized, with one vent open. For water-cooled units, shut and lock the cooling water valve.

Air Filter Replacement

Remove the filter weekly and blow from inside to outside with 0.2–0.4 MPa compressed air.
When replacing, ensure the seal is tight to prevent unfiltered air from entering.

Oil Filter Replacement

Run the compressor for about 5 minutes to warm the oil to above 50°C.
After depressurizing the system, open the oil drain valve slowly.
Before installing a new filter, apply a thin layer of compressor oil on the gasket, and hand-tighten—do not overtighten.

Oil Separator Replacement

Ensure the top and bottom asbestos gaskets are pinned and properly aligned during tightening to avoid leakage.
While reinstalling the return oil pipe, avoid bending it.
Its end should be centered and 2–4 mm above the separator’s bottom.

Screw Compressor Oil Replacement

Drain the old oil completely, then refill to the correct level on the oil sight glass.
Do not mix different lubricant brands.
It is recommended to replace the oil filter at the same time.

04

Risks of Overdue Components: Small Neglect, Big Losses

• Air Filter: Increased intake resistance leads to higher actual compression ratio, heavier load, and shortened airend life. A damaged filter may allow debris into the airend, causing seizure or total failure.

• Oil Filter: When clogged, pressure exceeds the bypass valve limit, causing it to open. Unfiltered oil enters the airend, leading to accelerated wear.

• Oil Separator: Reduced separation efficiency increases oil carryover, raises oil consumption, and may cause separator failure or abnormal oil loss.

• Compressor Oil: Degraded oil loses its lubrication, cooling, and sealing properties, causing high temperatures, wear, or even machine breakdown.

05

Practical Tips

• Keep detailed maintenance records: replacement time, parts model, operating hours.

• Watch for warning signs: abnormal noise, increased oil carryover, rising energy consumption—all indicate it’s time to check the filters and oil.

• Always choose genuine parts. Poor-quality filters may cause more harm than good.

• Regularly drain condensate water: weekly for normal conditions, every 2–3 days in hot and humid environments.

Regularly replacing the “three filters + one oil” is the foundation of compressor maintenance. Following proper intervals and procedures not only ensures stable operation and extended service life but also reduces energy consumption and prevents costly breakdowns.

Good equipment lasts when properly maintained—not when repaired after damage. This investment is always worthwhile.