It should not be confused with a vent limiting device (vLimiter) which is installed in the vent connection to manage diaphragm relief

OEM Compatibility: Specifically designed for Lennox G26Q3

Ensure the burner ground is secure to allow for proper flame rectification sensing

Precise Modulation: The 8-13 psi spring range allows for accurate pneumatic control in both modulating and on/off sequences

The Armstrong International A9739 Thermostat Air Vent is a critical OEM replacement part designed specifically for "A"

Zonefirst ZDB-12X18 12HX18W Parallel 24V 2-Pos S/R THPU32HP7Y It should not be confusedThe Zonefirst ZDB 12X18 is a professional grade 12HX18W Parallel 24V 2 Pos S R zone damper engineered for high static HVAC environments. Built with a heavy duty extruded aluminum frame and 3 inch parallel blades, this bottom mount zone damper ensures quiet, low leakage performance in rectangular ductwork. The unit utilizes a 2 wire spring return motor rated for 24VAC, providing a fail safe open position when de energized and a powered closed state.