this is specifically an HSI (Hot Surface Ignition) module

It is widely used in Maxon's industrial line

Multi-Circuit Support: Capable of controlling up to three separate refrigeration circuits for commercial A/C and heat pump systems

the 125-degree thermal limit switch prevents catastrophic component failure

the cut-in temperature will naturally remain 20°F above that setting

Setra 2651005WDABT1C Pressure Transducer 30067439-890 this is specifically an HSIThe Setra 2651005WDABT1C is a professional grade low differential pressure transducer engineered for precision monitoring in HVAC systems and VAV box control. This unit provides a 0 to 5" WC unidirectional pressure range, delivering highly accurate readings essential for maintaining static pressure and industrial airflow requirements. As the direct replacement for DPT2650 005D AB, it ensures seamless integration into existing building automation