Industrial ST171400AV Air Compressor Pilot Unloader Check Valve

ST171400AV is a piloted unloader valve designed for RIDGID and Campbell Hausfeld air compressors, most notably the AD10 platform. The assembly integrates the pilot valve, head-unloader function, and a check valve in a single housing, coordinating the pump-down and restart sequence by venting the compressor head at shutdown and allowing a smooth restart when pressure falls to the pull-down setting. In supplier catalogs, the part is listed as ST171400AV and is also found under the GP90150A designation as a replacement for RIDGID/Campbell Hausfeld units. This unloader/check valve assembly manages air flow during the compressor’s start/stop cycle, helping prevent pressure surges and reduce wear on the pump and motor through controlled unloading of head pressure prior to re-energizing the system.