External Liquid Level Switch
Model R

The Model R is an compact external service liquid level switch. The body style, with its top and bottom process connections, allows easy installation using straight-through piping. Models are available for service up to 250 PSIG with an operating temperature up to 500 F and specific gravity as low as 0.6.


Float Chamber: The float chamber is cast iron. Refer to the Model CB if other materials are required.
Float: A 2-1/2" round float is available in copper or 316 SS.
Trim: The float rod and its related hardware are 300 series stainless steel.
Specific Gravity: The Minimum standard specific gravity is 0.8. Lower is available upon request.
Mounting and Process Connections: The unit is mounted externally to the tank or vessel using 3/4" NPT female connections. One inch NPT connections are available through an adapter at added cost.
Differential: The fixed differential is 3/4". The switch actuation point is not adjustable.
Switch Housing: A water-tight/dust-tight housing is standard.
Switches: See Model V.
Conduit Connection: 1/2" NPT.

Optional Features:

Corrosion-Resistant Coating: To provide added protection in corrosive applications, the float and/or magnetic armatures are available with a Teflon coating.


Starting in the unactuated position, a rising liquid level will lift the float and rod, pivoting the magnetic armature towards the barrier plate. A permanent magnet, located within the switch assembly, snaps forward from the magnetic attraction. In doing so, the plunger is depressed, actuating the switch assembly. When the level decreases, the float falls away, pulling the armature to its original position, releasing the permanent magnet, re-setting the switch assembly to its unactuated position.