The LiftMaster K21-14182 Transformer, 1PH Dual Voltage is an OEM control transformer designed for select LiftMaster commercial door operator platforms. It converts incoming line power to the low-voltage control supply required by the operator’s logic board, accessories, and safety circuits, restoring stable performance when the original transformer has failed. Intended for single-phase systems, this dual-voltage unit supports operation in a variety of commercial environments where LiftMaster jackshaft, hoist, or trolley operators are used, such as warehouses, loading docks, and industrial facilities.
As a dual-voltage component, the primary is configured to match one of two supported supply options as indicated on the transformer label and the operator’s wiring diagram, while the secondary delivers the control power specified for the particular operator model. Compatibility is model-specific; verify K21-14182 against your operator’s parts breakdown or LiftMaster technical documentation for your exact model and serial range. For safety and reliability, installation should be performed by a qualified technician with power locked out, primary taps set for the site’s supply, and all connections made per the LiftMaster schematic to prevent damage to the control circuitry. This is a genuine LiftMaster replacement part for single-phase commercial operator systems and is not intended as a universal retrofit for non-LiftMaster equipment.