Honeywell Gas boiler control unit S4960B1055U

The Honeywell S4960B1055U is a gas boiler control unit, type designation VK41, designed for use with gas regulators from the VK41 series. It operates on a supply voltage of 220–240 V and features a connector on the top for simplified installation. This control unit does not interact directly with the flame; instead, it coordinates ignition and flame monitoring in systems with automatic ignition, including spark ignition (DBI) and pilot burner (IP) configurations. It is part of a joint control and ignition system (CVI) that optimizes burner operation.

Control units of this type are selected based on compatibility with the gas regulator series and the ignition system used (spark or pilot burner). The supply voltage must match the equipment's electrical circuit, typically 220–240 V. Installation involves connecting the unit to the gas regulator via the top-mounted connector, and the unit can be positioned within a 90-degree angle in any direction from the vertical. Before ordering, verify the type designation and ensure the connector matches the regulator.

When control units of this kind fail, the burner may fail to ignite or experience intermittent flame loss, leading to system lockouts. The equipment might show error codes or fail to start altogether. Check for loose connections, damaged wiring, or signs of overheating on the control unit. If the unit does not respond to power, test the supply voltage and inspect the connector for corrosion or damage.