The Trane SWT2173 Rollout Switch (SKU: SWT02173) is a critical OEM furnace safety component designed to break the 24V control circuit when it detects flame rollout or excessive heat at the burner box

the "/U" suffix simply denotes the retail-packaged universal version of the same Honeywell ignition cable

Designed to withstand the demanding pressures of industrial process steam

This relay operates on a 24VAC control circuit

Proper installation involves verifying the L190-30F specifications to match the original equipment manufacturer’s requirements for airflow and heat rise safety

Schneider Electric (Barber Colman) 2378-501 Relay Els PW 17895 The Trane SWT2173 Rollout SwitchThe Schneider Electric (Barber Colman) 2378 501 Relay is a high performance pneumatic amplifying relay designed for proportional signal control in HVAC systems. Engineered as a Pneumodular component, this device provides a definitive 2: 1 amplifying function, doubling the input signal pressure to the branch line. This is essential for contractors managing larger actuators or terminal units that require higher pressure than the standard controller