The Maxitrol SC11S-B is a professional-grade analog signal conditioner designed for precise gas modulation control in both direct and indirect-fired HVACR systems. As the direct replacement for SC11S, this track-mounted component integrates seamlessly into existing Maxitrol Selectra series installations. It is engineered to accept standard 4-20mA or 0-10 VDC input signals, converting them into a regulated 0-20 VDC output to drive modulating gas valves. One critical technical feature of the SC11S-B conditioner is the adjustable low fire start timer, which ensures the modulator output is fixed during the initial start sequence for optimal combustion stability. This HVAC signal converter supports a maximum load of 1.8 A and requires a 24V AC, 20 VA power supply. When deploying the Maxitrol modulating valve controller, ensure that the transformer secondary is not grounded to prevent internal damage to the circuitry. Key Benefits Universal Field Integration: Features an on-board 3-position DIP switch for easy toggling between 4-20mA and 0-10 VDC input protocols. Enhanced System Stability: The integrated low fire start timer prevents nuisance lockouts by maintaining a stable valve voltage during the ignition cycle. Multi-Valve Capability: Designed with a high output capacity to drive multiple Selectra modulating valves simultaneously from a single control signal. Rugged Design: Track-mounted for rapid installation in control cabinets, with an operations range of -40° to 158°F. Common Questions Is the SC11S-B compatible with older SC11S installations? Yes, the SC11S-B is the direct replacement for the legacy SC11S model and fits the same track-mounted footprint for straightforward field swaps. How do I configure the input signal type? Input selection is handled via the internal DIP switches. For 4-20mA operation, all switch positions should be set to "on," while 0-10 VDC requires all positions to be "off." Can I use a grounded transformer with this unit? No. To avoid damaging the signal conditioner, the transformer secondary must not be grounded in any part of the external circuit. Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.
