US Motors 3274 Replacement SPDT Proof of Closure Switch

The US Motors 3274 is a replacement Single-Pole Double-Throw (SPDT) Proof of Closure Switch designed to confirm the fully closed position of dampers, valves, or actuators in HVAC and building automation systems. This switch provides a critical safety and control signal, ensuring that downstream equipment — such as air handling units, boilers, or ventilation systems — only operate when the associated damper or valve has achieved its fully closed position.

Key Features

• SPDT (Single-Pole Double-Throw) switching action for versatile control circuit integration
• Proof of closure functionality confirms damper or valve is fully closed before allowing system operation
• Direct replacement part engineered to US Motors specifications
• Compatible with US Motors actuators and damper drive applications
• Supports both normally open (NO) and normally closed (NC) circuit configurations
• Compact, durable construction suited for commercial and industrial HVAC environments

Typical Applications

• Damper actuator position confirmation in air handling units (AHUs)
• Valve closure verification in hydronic and steam systems
• Interlock circuits for boilers, furnaces, and ventilation equipment
• Building automation and direct digital control (DDC) systems
• Safety interlock sequences requiring confirmed closed-position feedback

Why Choose the US Motors 3274?

Using a genuine US Motors replacement switch ensures proper fit, reliable electrical contact, and accurate position feedback — helping maintain system safety and operational integrity. Substituting off-spec switches can result in nuisance lockouts or, more critically, unsafe equipment operation. The 3274 is the correct factory-specified replacement for US Motors actuator assemblies requiring SPDT proof of closure switching.