McDonnell & Miller

McDonnell & Miller

Boiler Controls. McDonnell & Miller Low Water cut-offs are specially designed to protect steam and hot water boilers from the hazards of a low water condition. In operation they will interrupt the electrical current to the firing device, if the water in the system drops below the boiler manufacturer’s minimum safe water level. Our low water cut-offs also provide an additional circuit for a low water alarm, should you desire to install one, for additional protection.

If you have any questions please give us a call at 1-800-781-7405 or email us your request. Sales@NationalPumpSupply.com

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  • 120601 McDonnell & Miller FS8-W - 1" Flow Switch

    120601 McDonnell & Miller FS8-W - 1" Flow Switch

    McDonnell & Miller

    $184.95
    120601 McDonnell & Miller FS8-W - 1" Flow Switch General purpose flow switch w/NEMA 4X enclosure 120601. Mcdonnell & Miller 120601 Instruction Manual For general purpose applications with environmental exposure, or those requiring a...
    $184.95
    Qty in Cart: 0
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    $184.95
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  • 120611 McDonnell & Miller FS251

    120611 McDonnell & Miller FS251 Flow Switch With NEMA 1 Enclosure

    McDonnell & Miller

    $138.95
    McDonnell & Miller FS251 General Purpose Flow Switch With NEMA 1 Enclosure 120611, Replaces FS4-3. Information: McDonnell & Miller FS4 Brochure McDonnell & Miller FS4 Instruction Manual Features Universal design serves the widest...
    $138.95
    Qty in Cart: 0
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    $138.95
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  • 114400 McDonnell & Miller FS4-3 1" Flow Switch 1" NPT

    114400 McDonnell & Miller FS4-3 1" Flow Switch

    McDonnell & Miller

    $134.95
    114400 McDonnell & Miller FS4-3 1" Flow Switch 1" NPT. Click here for more info on Mcdonnell Miller Flow Switches Universal design serves the widest variety of applications. For starting or stopping electrically operated equipment such as signal...
    $134.95
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    $134.95
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  • 120610 McDonnell & Miller FS254 Flow Switch

    120610 McDonnell & Miller FS254 Flow Switch With NEMA 4 Enclosure

    McDonnell & Miller

    $178.95
    120610 McDonnell & Miller FS254 Flow Switch With NEMA 4 Enclosure, Replaces FS8-W. McDonnell & Miller FS254 Brochure Features: Universal design serves the widest variety of applications For starting or stopping electrically operated equipment...
    $178.95
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    $178.95
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  • 113200 McDonnell & Miller FS-1 1/2" Liquid Flow Switch

    113200 McDonnell & Miller FS-1 1/2" Liquid Flow Switch

    McDonnell & Miller

    $214.95
    113200 McDonnell & Miller FS-1 1/2" Liquid Flow Switch. McDonnell & Miller FS1 Instruction Manual Features: For general purpose applications where high sensitivity is required and moderate or low flow rates are encountered such as air...
    $214.95
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    $214.95
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  • 114639 McDonnell & Miller FS4-3RP-T 1" Flow Switch FS4-3 With Test Button

    114639 McDonnell & Miller FS4-3RP-T 1" Flow Switch

    McDonnell & Miller

    $178.95
    114639 McDonnell & Miller FS4-3RP-T 1" Flow Switch FS4-3 With Test Button. McDonnell & Miller FS4 Brochure McDonnell & Miller FS4 Instruction Manual Universal design serves the widest variety of applications. For starting or stopping...
    $178.95
    Qty in Cart: 0
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  • 123400 McDonnell & Miller Air Flow Switch Model AF3

    123400 McDonnell & Miller AF3 Air Flow Switch

    McDonnell & Miller

    $149.95
    123400 McDonnell & Miller Air Flow Switch Model AF3. McDonnell & Miller AF1 Flow Switch Instruction Manual For general purpose low velocity applications where the most economical flow switch is desired. Paddle fits 8" (203mm) minimum...
    $149.95
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    $149.95
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  • 123000 McDonnell & Miller Air Flow Switch Model AF1-S

    123000 McDonnell & Miller Air Flow Switch AF1-S

    McDonnell & Miller

    $292.95
    123000 McDonnell & Miller Air Flow Switch AF1-S. Mcdonnell & Miller AF1 Flow Switch Instruction Manual For general purpose applications with medium and high velocity requirements: Paddle fits 8" (203mm) minimum duct size, or 6" (152mm) if...
    $292.95
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    $292.95
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  • 114780 McDonnell & Miller FS5-1 - 1" Flow Switch

    114780 McDonnell & Miller FS5-1 - 1" Flow Switch

    McDonnell & Miller

    $224.95
    114780 McDonnell & Miller FS5-1 - 1" Flow Switch 114780. McDonnell & Miller FS5 Instruction Manual Features: In-line configuration eliminates need for a pipe tee Sizes available: 3/4" NPT, 1" NPT Materials of construction: Brass, carbon &...
    $224.95
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    $224.95
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  • 126400 McDonnell & Miller Make-Up Water Feeder Model 21

    126400 McDonnell & Miller 21 Make-Up Water Feeder Model 21

    McDonnell & Miller

    $572.95
    126400 McDonnell & Miller Make-Up Water Feeder Model 21. Mcdonnell & Miller Model 21 Instruction Manual For boiler receiver tanks Direct mounting eliminates need for equalizing connections Proportional feed action Mounting Flange – six...
    $572.95
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    $572.95
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  • 169550 McDonnell & Miller Universal Water Feeder Uni-Match WFE-24V

    169550 McDonnell & Miller WFE-24V Universal Water Feeder Uni-Match

    McDonnell & Miller

    $278.95
    169550 McDonnell & Miller Universal Water Feeder Uni-Match WFE-24V. McDonnell & Miller WFE-24V Instruction Manual McDonnell & Miller Universal Water Feeders are ideal for use in residential or small commercial applications. Versatile...
    $278.95
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    $278.95
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  • 114760 McDonnell & Miller FS5-3/4 - 3/4" Flow Switch

    114760 McDonnell & Miller FS5-3/4 - 3/4" Flow Switch

    McDonnell & Miller

    $224.95
    114760 McDonnell & Miller FS5-3/4 - 3/4" Flow Switch 114760. Information: McDonnell & Miller FS5 Instruction Manual Features: For general purpose applications requiring low flow rate sensitivity In-line configuration eliminates need for a pipe...
    $224.95
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  • 153900 McDonnell & Miller Low Water Cut Off 69

    153900 McDonnell & Miller Low Water Cut Off 69

    McDonnell & Miller

    $262.95
     153900 McDonnell & Miller Mechanical Low Water Cut Off 69. Float Type Low Water Cut Off For Millivolt Service. Information: Mcdonnell & Miller LWCO Model 69 General Catalog Mcdonnell & Miller LWCO Model 69 Installation Manual ...
    $262.95
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    $262.95
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  • 119700 McDonnell & Miller FS7-4 - 1-1/4" Flow Switch

    119700 McDonnell & Miller FS7-4 - 1-1/4" Flow Switch

    McDonnell & Miller

    $359.95
    119700 McDonnell & Miller FS7-4 - 1-1/4" Flow Switch Paddle Style. McDonnell & Miller FS7 Overview McDonnell & Miller FS7 Instruction Manual Features: Universal design serves the widest variety of large pipe applications, including heating...
    $359.95
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    $359.95
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  • 126800 McDonnell & Miller 25-A Make-Up Water Feeder

    126800 McDonnell & Miller 25-A Make-Up Water Feeder

    McDonnell & Miller

    $864.95
    126800 McDonnell & Miller Make-Up Water Feeder Model 25-A. McDonnell & Miller Model 21 Water Feeder Instruction Manual Features: For boiler receiver tanks Float operated Proportional feed action Soft seat provides positive seal Seal between...
    $864.95
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    $864.95
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  • 114900 McDonnell & Miller FS4-3T2-3/4 - 3/4" Flow Switch

    114900 McDonnell & Miller FS4-3T2-3/4 - 3/4" Flow Switch

    McDonnell & Miller

    $214.95
    114900 McDonnell & Miller FS4-3T2-3/4 - 3/4" Flow Switch With NPT Body Medium Flow Rate 114900. McDonnell & Miller FS4 Instruction Manual Features: For starting or stopping electrically operated equipment such as signal lights, alarms, motors,...
    $214.95
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    $214.95
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  • 181525 McDonnell & Miller Relief Valve 250-3/4-50 - 3/4" NPT

    181525 McDonnell & Miller Relief Valve 250-3/4-50 - 3/4" NPT

    McDonnell & Miller

    $124.95
    181525 McDonnell & Miller Relief Valve 250-3/4-50 - 3/4" NPT. Features and Benefits: For tanks and hydronic heating systems Protects against over-pressure Minimizes hammering with flash steam Low differential pressure – 3 psi (.21 kg/cm2)...
    $124.95
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    $124.95
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  • 115400 McDonnell & Miller FS6-3/4 - 3/4" Flow Switch

    McDonnell & Miller

    $334.95
    115400 McDonnell & Miller FS6-3/4 - 3/4" Flow Switch-High Sensitivity. McDonnell & Miller FS6 Instruction Manual This Mcdonnell & Miller flow swicth is for heavy duty applications where high sensitivity is required, such as water treatment...
    $334.95
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    $334.95
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  • 120160 McDonnell & Miller FS7-4S - 1-1/4" Flow Switch

    120160 McDonnell & Miller FS7-4S - 1-1/4" Flow Switch

    McDonnell & Miller

    $598.95
    120160 McDonnell & Miller FS7-4S - 1-1/4" Flow Switch With Stainless Steel Body 120160. Mcdonnell & Miller 120160 Instruction Manual Features: Universal design serves the widest variety of large pipe applications, including heating and hydronic...
    $598.95
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    $598.95
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  • 171702 McDonnell & Miller Hi Pressure Level Control 150S

    171702 McDonnell & Miller Hi Pressure Level Control 150S

    McDonnell & Miller

    $768.95
    171702 McDonnell & Miller Hi Pressure Level Control 150S. McDonnell & Miller 150S Instruction Manual Features and Benefits For commercial and industrial low or high pressure Boiler applications For boilers of any steaming...
    $768.95
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    $768.95
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