The Siebe Invensys MSC-P1501 Environmental Controls Controller is an MSC-series 24 VAC environmental control module designed to manage HVAC and environmental subsystems in commercial facilities. It operates from a 24 VAC supply with a maximum load of 101 VA and supports 50/60 Hz operation. The controller provides 24 VAC control outputs rated up to 12 VA, enabling direct interfacing with relays, valves, and actuators within environmental control circuits. While the MSC-P1501 is an older model, multiple distributor listings confirm it was discontinued by the manufacturer, though used units remain available in secondary markets.
