AirComParts Centrifugal Unloader Assembly for Kellogg-American 321, 332, 335 and 452 Air Compressor Pumps

Replacement centrifugal unloader assembly, Kellogg reference 48870, for Kellogg-American 321, 332, 335 and 452 two-stage air compressor pumps. Supplied by AirComParts under the ACS Kellogg clone replacement line.

The centrifugal unloader is what lets the motor start. It holds the pump unloaded while the crankshaft comes up to speed, then its flyweights throw out and the pump begins compressing. When the unloader sticks, wears or loses a weight, the pump tries to start against full head pressure: the motor stalls, the overload trips, belts squeal and burn, and on single-phase machines the start capacitor usually goes with it. A compressor that trips its breaker on start but runs fine once it is turning is the classic symptom.

Part reference

• K4085: Kellogg reference 48870, centrifugal unloader assembly, complete with weights

Pump fitment

• 321 / 321TV: 1 to 2 HP, two-stage, two-cylinder, 7.4 CFM at 175 PSI
• 332 / 332TV / 332TVX: 3 to 7.5 HP, two-stage, two-cylinder
• 335 / 335TV / 335TVX: 3 to 5 HP, two-stage, two-cylinder, 17.2 CFM at 175 PSI
• 452 / 452TV / 452TVX: 7.5 to 10 HP, two-stage, four-cylinder, 35.2 CFM at 175 PSI

Check the unloader valve too

The centrifugal assembly works with a release valve that vents the trapped air. If the pump still labours on start after a new unloader assembly, the valve or its line is the next thing to look at. Replacing both together is normal practice on a pump that has been tripping out.

AirComParts replacement centrifugal unloader assembly with weights, Kellogg 48870, fitting the Kellogg-American 321, 332, 335 and 452 air compressor pumps. Stocked at the Warthog Air Compressor Store alongside the full ACS Kellogg-style pump parts range: crankshafts, pistons, cylinders, heads, valve cages, intercoolers and gasket sets. Tell us the number cast on your crankcase and we will confirm fitment.