Atlas Copco unloader / inlet valve assembly

Combined inlet throttle and non-return assembly mounted directly on the GA/GX airend suction flange.

Also called: unloader valve GA · 1622 series inlet valve

How it works

Y1 control air lifts the internal piston, opening the throttle disc for full flow. At unload the piston vents and the disc closes; the integral non-return prevents blowback through the filter while the blowdown drops sump pressure.

Specifications

Service kit

Piston seal, disc seal, spring, O-rings (2901 xxxx xx kits)

Inspection

At each separator/oil service

Parts you can order

• Atlas Copco (OEM)

  Unloader valve service kit

  Serial-specific (2901 / 1622 families)

  $120 – $480

Field test procedure

1. Remove the intake hose: oil pooling in the filter housing is a failed non-return.
2. Bench-stroke the actuator on 60 PSIG shop air.

Symptoms & probable causes

• Air filter housing full of oil
  Non-return seal failed.
• Element service warning early / restricted flow
  Disc not opening fully.