this is a 3

What is the difference between the MA51-7100 and MA51-7100-000

This component is engineered for the Robertshaw 1820 and 1830 series

Standardized Fit: Features a rugged 1/4" NPT threaded connection for universal compatibility with standard drain valves and pipes

For veteran HVACR technicians

Warrick 26MB1A0A Control 30067439-890 this is a 3The Warrick 26MB1A0A is a heavy duty, solid state liquid level control designed specifically for boiler low water cutoff protection. Engineered with a 10,000 ohm sensitivity, this direct acting module ensures high reliability switching in conductive liquid systems, meeting strict CSD1 requirements for industrial boiler safety. This 120Vac unit utilizes an 11 pin octal socket design for seamless plug in module replacement and field installation,