MCDONNELL & MILLER

The company's catalogue includes a wide variety of boiler controls, valves, water feeders and flow switches. General-purpose brass flow switches by McDonnell & Miller come with a screw that adjusts the sensitivity and allows flow rates up to 131 GPM at a maximum pressure and temperature of 160 psi and 250 degrees F, respectively. They also feature sealed EPDM O-rings providing excellent resistance to chemicals and creating a bubble-tight barrier for a leak-free operation. These switches are ideal for applications requiring low flow rate sensitivity, such as signal lights, alarms, metering devices and automatic burners.

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MCDONNELL & MILLER Flow Switches

Flow SwitchesSuitable for motors, automatic burners, signal lights, alarms and metering devices. Feature a maximum flow rate and of 131 gpm and 1000 psi, respectively(36 Products)

MCDONNELL & MILLER Parts

PartsIncludes bronze / stainless-steel paddle kits designed for use with general-purpose liquid flow switches. Offered in packs of 2 and 4(18 Products)

MCDONNELL & MILLER Water Level Controls

Water Level Controls(71 Products)

MCDONNELL & MILLER Sensing Probes

Sensing Probes(9 Products)

MCDONNELL & MILLER Valve Accessories

Valve Accessories(8 Products)

MCDONNELL & MILLER Gears

Gears(4 Products)

MCDONNELL & MILLER Boiler Accessories

Boiler Accessories(3 Products)

MCDONNELL & MILLER Liquid Level Gauges

Liquid Level Gauges(3 Products)

MCDONNELL & MILLER Faucet Repair Parts

Faucet Repair Parts(2 Products)

MCDONNELL & MILLER Hydraulic Valves

Hydraulic Valves(2 Products)

MCDONNELL & MILLER Pump Control Boxes

Pump Control Boxes(2 Products)

MCDONNELL & MILLER Relief Valves

Relief Valves(2 Products)

MCDONNELL & MILLER Specialty Switches

Specialty Switches(2 Products)

MCDONNELL & MILLER Ball Valves

Ball Valves(1 Product)

MCDONNELL & MILLER Float Balls

Float Balls(1 Product)

MCDONNELL & MILLER Fuel Systems Tools

Fuel Systems Tools(1 Product)

MCDONNELL & MILLER Pneumatic Controls

Pneumatic Controls(1 Product)

MCDONNELL & MILLER Switch Accessories

Switch Accessories(1 Product)

MCDONNELL & MILLER Tubing

Tubing(1 Product)

MCDONNELL & MILLER Vacuum Breakers

Vacuum Breakers(1 Product)

Things To Consider

Shipping

McDonnell & Miller products range from small to large sizes. They may require careful packaging as some items might get damaged while shipping. Hence, these items are delivered by courier shipment and air freight for minimum downtime.

About Mcdonnell & Miller

The company's catalogue includes a wide variety of boiler controls, valves, water feeders and flow switches. General-purpose brass flow switches by McDonnell & Miller come with a screw that adjusts the sensitivity and allows flow rates up to 131 GPM at a maximum pressure and temperature of 160 psi and 250 degrees F, respectively. They also feature sealed EPDM O-rings providing excellent resistance to chemicals and creating a bubble-tight barrier for a leak-free operation. These switches are ideal for applications requiring low flow rate sensitivity, such as signal lights, alarms, metering devices and automatic burners.

Major Trade Names

RB-24E Series Low Water Cut-Off

RB-24E Series Low Water Cut-Off

They are designed for turning off the burner or shutting off fuel to prevent it from running once the water drops below a certain point, thereby eliminating the risk of rupture or catastrophic failure in the system. They feature brass threads for leak-proof sealing and a plug-and-play wiring harness...

for quick mounting in tight spaces.

42S Series Pump Controllers

42S Series Pump Controllers

These pump controllers are ideal for industrial and commercial low or high-pressure steam boilers. They feature Monel bellows to provide excellent corrosion resistance and an enclosed junction box that protects the switches within the system. They may include optional features like quick hook-up fit...

tings for simplifying installations and gauge glass to view and monitor liquid levels.

High-Sensitivity Liquid Flow Switches

High-Sensitivity Liquid Flow Switches

These switches are suitable for applications where high sensitivity is required, including water treatment systems, compressors, cooling systems for electronic circuits, booster pumps and bearings. They have an SPDT switch, a sensitivity adjustment screw and an enclosed switch compartment. These swi...

tches offer in-line configuration to eliminate the need for a pipe tee to combine or divide fluid flow.

Mcdonnell & Miller Competitive Advantages

WFE Uni-Match Electronic Feeder

WFE Uni-Match Electronic Feeder

These universal water feeders are used in small commercial steam boilers to automatically add water to the boiler when a signal is given from the LWCO (low water cut-off) device. They feature field-adjustable dwell-feed cycles to reduce the chances of flooding the system, a manual feed button to add water at any time (irrespective of the feed cycle...

), a multi-colour LED for making verification of operation and troubleshooting simple and a dwell / feed selector switch with four on / off switches for selecting appropriate feed cycles (up to 5 cycles).

Frequently Asked Questions

How does an SPDT flow switch work?

  • An SPDT (single pole, double throw) flow switch helps to detect the flow of liquids or gases in a system. This electronic configuration comprises normally open (NO) and normally closed (NC) terminals. The working of the switch depends on these terminals, acting under different conditions.
  • When there is no flow in the system, the switch is in the normal state, and the NO terminal is open while the NC terminal is closed.
  • When flow is detected, the switch actuates and the NO terminal closes while the NC terminal opens.

What is the purpose of NEMA enclosures?

NEMA (National Electrical Manufacturers Association) enclosures protect electrical equipment from a variety of environmental hazards like dust, water and debris. They are made of different materials and can be used in both indoor and outdoor applications. They are rated differently to provide protection against different types of external factors. For example, NEMA 1 enclosure protects against dust, while NEMA 4 provides protection against dust, water and corrosive materials.

What is the use of a bellow in pump controllers?

A bellow is made of a flexible material that expands or contracts in response to changes in fluid pressure, which in turn activates a switch or relay to turn the pump on or off.