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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129302 McDonnell & Miller 42S Pump Controller LWCO
McDonnell & Miller
$979.95129302 McDonnell & Miller Pump Controller LWCO 42S. Instruction Manual Features: For Residential, Commercial, & Industrial low and medium pressure steam boilers with a separate water column For boilers of any steaming...$979.95 -
153928 McDonnell & Miller PSE-802-U-24 Low Water Cut Off
McDonnell & Miller
$364.95153928 McDonnell & Miller PSE-802-U-24 Low Water Cut Off. The Series PSE-800 probe type LWCO uses patented technology to monitor changes in water conductivity. When defined parameters are exceeded the new PSE-800 makes a decision to shut the...$364.95 -
123200 McDonnell & Miller AF2 Air Flow Switch Model AF2
McDonnell & Miller
$348.95123200 McDonnell & Miller Air Flow Switch Model AF2. McDonnell & Miller AF1 Flow Switch Instruction Manual For low velocity applications: Paddle fits 8" (203mm) minimum duct size Two electrical knock-outs allow connection from either...$348.95 -
120603 McDonnell & Miller FS8-WG - 1" Flow Switch
McDonnell & Miller
120603 McDonnell & Miller FS8-WG - 1" Flow Switch With Gold Plated Switch Contacts 120603. 120603 McDonnell & Miller Instruction Manual Features: For general purpose applications with environmental exposure, or those requiring a...Qty in Cart: 0Quantity:Price:Subtotal: -
115652 McDonnell & Miller FS6-W-1 - 1" Flow Switch
McDonnell & Miller
$584.95115652 McDonnell & Miller FS6-W-1 - 1" Flow Switch With NEMA 4X Enclosure. McDonnell & Miller FS6 Instruction Manual This McDonnell & Miller flow switch is for heavy duty applications where high sensitivity is required, such as water...$584.95 -
120060 McDonnell & Miller FS7-4J Flow Switch 1-1 4 BSTP
McDonnell & Miller
$574.95120060 McDonnell & Miller FS7-4J Flow Switch 1-1 4 BSTP. *Please note image is generic. McDonnell & Miller FS7 Overview McDonnell & Miller FS7 Instruction Manual Features: Universal design serves the widest variety of large...$574.95 -
153916 McDonnell & Miller PS-802-U-24 Low Water Cut-Off
McDonnell & Miller
$354.95153916 McDonnell & Miller PS-802-U-24 Low Water Cut-Off. This model has been replaced and the new model is 153928 PSE-802-U-24. This Item Usually Ships The Same Day!$354.95 -
123450 McDonnell & Miller AF3D Air Flow Switch
McDonnell & Miller
$264.95123450 McDonnell & Miller Air Flow Switch Model AF3D. McDonnell & Miller AFE-1 Instruction Manual For general purpose low velocity applications where the most economical flow switch is desired. Paddle fits 8" (203mm) minimum duct...$264.95 -
195000 McDonnell & Miller TC-4 Test & Check Valves
McDonnell & Miller
$737.95195000 McDonnell & Miller TC-4 Test & Check Valves. Information: 195000 Mcdonnell & Miller TC-4 Instruction Manual Features and Benefits: For use on hot water boilers Simplifies ASME CSD-1A. code mandated testing of lowwater...$737.95 -
176902 McDonnell & Miller 157S-RL Hi Pressure Level Control
McDonnell & Miller
$1,558.95176902 McDonnell & Miller 157S-RL Hi Pressure Level Control. McDonnell & Miller 150S/157S Instruction Manual Specifications For boilers of any steaming capacity Monel bellows provides corrosion resistance Snap action switches for high...$1,558.95 -
169400 McDonnell & Miller Water Feeder 101A-120v
McDonnell & Miller
$504.95169400 McDonnell & Miller Water Feeder 101A-120v McDonnell & Miller 101-A Electric Water Feeder Instruction Manual Electric Water Feeder Features: For low pressure steam boilers with cold water feed Eliminates necessity to manually add...$504.95 -
153929-LWCO McDonnell & Miller PSE-802-RX2-24 Low Water Cut Off
McDonnell & Miller
$328.95153929-LWCO McDonnell & Miller PSE-802-RX2-24 Low Water Cut Off. The Series PSE-800 probe type LWCO uses patented technology to monitor changes in water conductivity. When defined parameters are exceeded the new PSE-800 makes a decision to shut...$328.95 -
114550 McDonnell & Miller FS4-3D 1" Flow Switch
McDonnell & Miller
$358.95McDonnell & Miller FS4-3D 1" Flow Switch 4-3 W/2 SPDT Switches 114550. McDonnell & Miller FS4 Brochure McDonnell & Miller FS4 Instruction Manual Universal design serves the widest variety of applications. For starting or stopping...$358.95 -
129502 McDonnell & Miller 42S-HD Head Mechanism
McDonnell & Miller
$874.95129502 McDonnell & Miller 42S-HD Head Mechanism for 42S, 42S-A. *Please note image is generic. This Item Usually Ships The Same Day!$874.95 -
162300 McDonnell & Miller 93 Low Water Cut-Off
McDonnell & Miller
$1,668.95162300 McDonnell & Miller Combination Control Model 93 Low Water Cut-Off. Information: McDonnell & Miller LWCO Instruction Manual Features: For commercial and industrial low or high pressure steam boilers Maintains consistent water...$1,668.95 -
113550 McDonnell & Miller FS1-J Flow Switch
McDonnell & Miller
$332.95113550 McDonnell & Miller FS1-J Flow Switch. *Please note image is generic. McDonnell & Miller FS1 Instruction Manual For general purpose applications where high sensitivity is required and moderate or low flow rates are encountered such as...$332.95 -
153601 McDonnell & Miller PSE-801-M-120 Probe Control
McDonnell & Miller
$308.95153601 McDonnell & Miller PSE-801-M-120 Probe Control with manual reset (steam) uses patented technology to monitor changes in water conductivity. When defined parameters are exceeded the new PSE-800 makes a decision to shut the burner off based...$308.95 -
181625 McDonnell & Miller Relief Valve 250-3/4-75
McDonnell & Miller
$184.95181625 McDonnell & Miller Relief Valve 250-3/4-75. 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)...$184.95 -
144692 McDonnell & Miller RB-24E Low Water Cut Off
McDonnell & Miller
$174.95144692 McDonnell & Miller RB-24E Low Water Cut Off. This Item Usually Ships The Same Day!$174.95 -
153602 McDonnell & Miller PSE-802-M-24 Low Water Cut Off
McDonnell & Miller
$378.95The series 153602 - McDonnell & Miller PSE-802-M-24 Low Water Cut Off. The Series PSE-800-M Manual Reset LWCO is a new addition to the McDonnell & Miller probe type low water cut-off group of products. These controls are used as the...$378.95 -
132900 McDonnell & Miller 47-2-M Mechanical Water Feeder
McDonnell & Miller
$1,258.95132900 McDonnell & Miller 47-2-M Mechanical Water Feeder. Features: For steam and hot water boilers with cold water feed Continuous maintenance of minimum safe water level, independent of electrical service Proportional feed action Quick...$1,258.95 -
120191 McDonnell & Miller FS7-4SW - 1-1/4" Flow Switch
McDonnell & Miller
$1,097.95120191 McDonnell & Miller FS7-4SW - 1-1/4" Flow Switch w/Stainless Steel Body And NEMA 4X Enclosure 120191. Mcdonnell & Miller 120191 Instruction Manual Features: For applications requiring a water-tight, dust-tight or a NEMA 4X...$1,097.95 -
114410 McDonnell & Miller FS4-3Z Flow Switch 1 NPT
McDonnell & Miller
$224.95114410 McDonnell & Miller FS4-3Z Flow Switch 1 NPT. This Item Usually Ships The Same Day!$224.95 -
181225 McDonnell & Miller Relief Valve 250-3/4-30
McDonnell & Miller
$184.95181225 McDonnell & Miller Relief Valve 250-3/4-30 Relief Valve 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...$184.95 -
176295 McDonnell & Miller 751P-MT-SP-120 LWCO
McDonnell & Miller
$328.95176295 McDonnell & Miller 751P-MT-SP-120 LWCO. The Series 751P/752P probe type LWCOs provide protection against low water conditions for commercial and industrial applications. These controls are fully CSD-1 compliant and are primarily used as...$328.95 -
171802 McDonnell & Miller Hi Pressure Level Control 150S-MD
McDonnell & Miller
$1,052.95171802 McDonnell & Miller Hi Pressure Level Control 150S-MD. Information: 171802 McDonnell & Miller 150S Instruction Manual Specifications For boilers of any steaming capacity Monel bellows provides corrosion resistance Snap action...$1,052.95 -
172702 McDonnell & Miller Hi Pressure Level Control 150S-M
McDonnell & Miller
$1,231.95172702 McDonnell & Miller Hi Pressure Level Control 150S-M. Information: 172702 McDonnell & Miller Instruction Manual Features and Benefits For commercial and industrial low or high pressure Boiler applications For boilers of...$1,231.95 -
149600 McDonnell & Miller 67-G Mechanical Low Water Cut Off
McDonnell & Miller
$624.95149600 McDonnell & Miller 67-G Mechanical Low Water Cut Off. Float Type Low Water Cut Off For Millivolt Service. Mcdonnell & Miller LWCO Series 67 Instruction Manual Mcdonnell & Miller LWCO Series 67 Submittal...$624.95 -
143100 McDonnell & Miller Mechanical LWCO 63M
McDonnell & Miller
$854.95142400 McDonnell & Miller Mechanical Low Water Cut Off 63. Mechanical LWCO For Steam Boilers. Information: Mcdonnell & Miller LWCO Series 63 Instruction Manual Features: For residential and commercial low pressure steam boiler...$854.95 -
135000 McDonnell & Miller Mechanical Water Feeder LWCO 51-2
McDonnell & Miller
$1,558.95135000 McDonnell & Miller Mechanical Water Feeder LWCO 51-2. Mcdonnell & Miller 135000 Instruction Manual Features: For low pressure steam and hot water boilers larger than 5,000 sq. ft. (465m2) capacity with cold water...$1,558.95 -
134900 McDonnell & Miller 51-HD Head Mechanism
McDonnell & Miller
$1,168.95134900 McDonnell & Miller 51-HD Head Mechanism for Mechanical Water Feeder. This Item Usually Ships The Same Day!$1,168.95 -
114800 McDonnell & Miller FS4-3T1-3/4 - 3/4" Flow Switch
McDonnell & Miller
$318.95114800 McDonnell & Miller FS4-3T1-3/4 - 3/4" Flow Switch. McDonnell & Miller FS4 Instruction Manual Features: For starting or stopping electrically operated equipment such as signal lights, alarms, motors, automatic burners, metering...$318.95 -
163100 McDonnell & Miller 93-7B-M Low Water Cut-Off
McDonnell & Miller
$2,321.95163100 McDonnell & Miller 93-7B-M Low Water Cut-Off. McDonnell & Miller LWCO Instruction Manual Features: For commercial and industrial low or high pressure steam boilers Maintains consistent water level regardless of pressure For...$2,321.95 -
110300 McDonnell & Miller Model 5 Reset Snap Switch
McDonnell & Miller
$998.95110300 McDonnell & Miller Model 5 Reset Snap Switch for model number 93, 193, 94, and 194 controls. This Item Usually Ships The Same Day!$998.95 -
176214 McDonnell & Miller 751P-MT-U-120 LWCO
McDonnell & Miller
$348.95176214 McDonnell & Miller 751P-MT-U-120 LWCO. Mcdonnell & Miller Series 751P/752P LWCO Brochure Mcdonnell & Miller Series 751P/752P LWCO Instruction Manual The Series 751P/752P probe type LWCOs provide protection...$348.95 -
135900 McDonnell & Miller 51-S-2 Mechanical Water Feeder
McDonnell & Miller
$1,728.95135900 McDonnell & Miller 51-S-2 Mechanical Water Feeder. Mcdonnell & Miller 135900 Instruction Manual Features: For high capacity [up to 35,000 sq. ft. (3250m2)] low pressure steam and hot water boilers with cold water feed Optional...$1,728.95 -
144676 McDonnell & Miller RB-122E Low Water Cut Off
McDonnell & Miller
$174.95144676 - McDonnell & Miller RB-122E Low Water Cut Off. This Item Usually Ships The Same Day!$174.95 -
354081 McDonnell & Miller PA-800 Probe Assembly
McDonnell & Miller
$114.95354081 McDonnell & Miller PA-800 354081 -Probe Assembly for 750, 750-MT-120, PS800, PS801, PS850, PS851. This Item Usually Ships The Same Day!$114.95 -
120100 McDonnell & Miller FS7-4E - 1-1/4" Flow Switch
McDonnell & Miller
$762.95120100 McDonnell & Miller FS7-4E - 1-1/4" Flow Switch With NEMA 7 & 9 Enclosure. McDonnell & Miller FS7 Overview McDonnell & Miller FS7 Instruction Manual Features: For hazardous environment applications requiring a NEMA 7...$762.95 -
127200 McDonnell & Miller 27-W Make-Up Water Feeder
McDonnell & Miller
$1,873.95127200 McDonnell & Miller Make-Up Water Feeder Model 27-W. Features: For commercial and industrial liquid level open tank applications Materials of construction: Brass, Monel valve seat, EPDM disc Maximum pressure 35 psi (2.5 kg/cm2) Maximum...$1,873.95