millivolt setups

you would typically look for the NC/S versions or a 4-wire variant

the 170°F high-limit is a manual reset

suitable for low-pressure steam and water applications

The McDonnell & Miller 750-HW-MT-120 (Part Number 176236) is a heavy-duty 120Vac high water cut-off designed to provide failsafe protection for steam boilers and hot water heating systems

McQuay 071278401 GAS VALVE R-410A millivolt setupsThe McQuay 071278401 GAS VALVE is a high precision fuel regulation component engineered for specific McQuay and Daikin Applied rooftop units and commercial furnaces. As a redundant gas valve, it features dual solenoid seats to ensure a positive shut off and meet stringent safety standards for industrial heating applications. Designed for seamless integration with 24V HVAC control circuits, this valve is a direct OEM spec replacement for the Daikin