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McDonnell & Miller General Catalogue Industrial Controls

McDonnell & Miller Series RB-24 – Probe Type Low Water Cut-Off

• Brass threads enable a secure and trouble-free installation
• Test button to confirm proper operation
• Universal wiring harness fits 100% of today’s gas boilers
• -S, -A, -B and -L models provide “plug & play” installation with most residential boilers
• Compact size
• Easy to install and wire
• Automatic reset feature resumes operations after a power outage when water is on probe
• Green LED indicating power is on
• Red LED indicating low water condition
• Solid state operation
• 15,000 ohms probe sensitivity
• Maximum ambient temperature 120°F (49°C)
• Maximum water temperature 250°F (121°C)
• Maximum water pressure of 160 psi (11.2 kg/cm2)

The McDonnel & Miller Series RB-24 probe type LWCOs provide protection against low water conditions. The RB-24 is for commercial and industrial applications. These controls are fully CSD-1 compliant. Furthermore they are primarily used as LWCOs on hot water heating boilers. If you need a different model other than those listed, please contact us at

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