Siemens Industrial Controls 3RU2136-4GB0 Relay 318973-401 it monitors the differential pressure

it monitors the differential pressure to confirm the inducer motor is moving sufficient combustion air

The Johnson Controls T-4002-303 Conversion Kit is a professional-grade solution designed for upgrading or replacing legacy pneumatic thermostats in commercial HVAC systems

For calculation of drive ratios

Efficient Performance: Features a 1075 RPM operating speed at 1/3 Horsepower for optimal energy-to-airflow ratio

this bellows-type pressure switch ensures high reliability and ultra-short bounce times

Siemens Industrial Controls 3RU2136-4GB0 Relay 318973-401 it monitors the differential pressureThe Siemens 3RU2136 4GB0 is a high performance thermal overload relay engineered for heavy duty motor protection within HVACR and industrial control systems. Designed specifically for SIRIUS size S2 applications, this unit provides precise monitoring for motors with a current rating between 36 and 45 Amps. The Class 10 tripping characteristic ensures reliable downtime prevention by responding to overcurrent and phase failure conditions before