Industrial Z4877 Low Pressure Intake Valve Unloader Assembly

Z4877 is the OEM low‑pressure intake valve/unloader assembly used on Champion and Gardner Denver air compressors. The PL30A operation/parts documentation lists Z4877 specifically as the Low Pressure Intake Valve/Unloader Assembly, confirming its role in Champion PL‑series equipment within the Gardner Denver family. This compact assembly fuses the intake valve with the unloading mechanism that governs airflow at the low‑pressure stage during unloading and restart, enabling controlled coast‑down and smoother start cycles without dwell at high intake pressures. Because it is an OEM part, Z4877 is sold under Champion/Gardner Denver branding and is stocked by multiple suppliers as the replacement unloader valve assembly for compatible compressors. Typical applications include piston‑type industrial air compressors in the Champion/Gardner Denver lineup that require a dedicated low‑pressure intake valve/unloader function to manage unloading sequences during load/unload cycles. For shop and field service, replacing the Z4877 assembly with the correct OEM part helps maintain original performance characteristics and serviceability of the low‑pressure head.