The Gardner Denver Auto‑Sentry ES 200EAU1173 is a multi‑compressor sequencing controller for rotary screw compressors, featuring built‑in motor starter, pressure control, and an RS‑232 port for data logging. Common failures on this model include faulty pressure sensor wiring, degraded contactors or relays in the starter circuit, and corrupted firmware causing “communication lost” errors; overheating of the controller board can also trigger over‑temperature shutdowns. Initial checks should verify proper 480 V AC supply to the unit, inspect all pressure sensor connections for continuity and correct voltage, and review any error codes displayed on the panel or via RS‑232 logs before proceeding to component replacement.[oss-gpt-20b]