The Orion Controls VCM‑X board is a modular E‑BUS controller used for HVAC zone and VAV unit management, featuring 7 analog inputs, 2 analog outputs, and up to 5 relay outputs with optional expansion modules. Common failure modes include power supply voltage drops causing loss of communication, shorted or open analog input lines leading to erroneous sensor readings, and relay contacts that burn out from overcurrent or mechanical wear. First‑check diagnostics: verify the 24 V DC rail and ensure proper grounding; inspect all analog I/O connections for continuity and correct wiring; review any stored error codes via the E‑BUS diagnostic interface before proceeding with component replacement.[oss-gpt-20b]