McDonnell & Miller Combination LWCO & Pump Controls

McDonnell & Miller Series 42S Low Water Cut-Off/Pump Controllers

Series 42S is for residential, commercial, and industrial low and medium-pressure steam boilers with a separate water column and boilers of any steaming capacity.

Features:

• Monel bellows provide corrosion resistance
• Single pole, single throw snap action switches
• Enclosed junction box protects switches
• Maximum pressure: 50 psi (3.5 kg/cm²)

Optional features:

• Quick hook-up fittings
• Gauge glass connector

McDonnell & Miller Series 93/193, 94/194 Low Water Cut-Off/Pump Controllers

Series 93/193, 94/194 LWCOs are for commercial and industrial low or high-pressure steam boilers.

Features:

• Maintains consistent water level regardless of pressure
• Water column with integral tappings for gauge glass and tri-cock installations
• For boilers of any steaming capacity
• No. 5 switch included
• Magnetic repulsion eliminates the need for bellows

Optional features:

• Manual reset
• 7B switch (135ohm proportional control signal) to maintain constant boiler water level
• 1" NPT connections
• Maximum pressure: 150 psi (10.5 kg/cm²) – Series 93/193
• Maximum pressure: 250 psi (17.6 kg/cm²) – Series 94/194

McDonnell & Miller Series 150S/157S Low Water Cut-Off/Pump Controllers

Series 150S/157S combination LWCO/pump controllers are ideal for commercial and industrial low or high-pressure boiler applications and boilers of any steaming capacity.

Features:

• Monel bellows provide corrosion resistance
• Snap action switches for high-temperature service
• One single pole, single throw switch for pump control
• One single pole, double throw switch for low water
• Cut-off and alarm actuation

Optional features:

• Manual reset
• Two single pole, single throw switches
• Two single pole, double throw switches
• Float block
• BSPT threads
• Maximum pressure: 150 psi (10.5 kg/cm²)
• Model 150S-MD features maximum differential operation – prevents nuisance burner shutdowns in low-pressure applications