#51-HD

• For low pressure steam and hot water boilers larger than
5,000 sq. ft. (465m2
) capacity with cold water feed
• Quick-change replaceable cartridge valve and strainer
• Optional features
– No. 2 switch  (pictured with the #2 switch)
– Manual reset
– Float block
• Proportional feed action
• Model 51 can be field upgraded with a No. 2 switch to
add low water cut-off function
• Maximum water supply pressure 150 psi (10.5 kg/cm2
)
• Maximum inlet water temperature 120˚F (49˚C)
• Maximum vessel pressure 35 psi (2.5 kg/cm2