top of page

Model BO:

Three way thermostatic valve

AMOT Model B Thermostatic Control Valves are fully automatic, 3-way fluid temperature control valves for diverting or mixing applications. They provide reliable control of fluid temperatures in engine jacket water and lubrication oil cooling systems. These valves are suitable for process control and industrial applications where fluids must be mixed or diverted depending on their temperatures. They may also be applied to cogeneration systems to control temperatures in the heat recovery loop assuring proper engine cooling and maximizing heat recovery.

Features and Benefits

  • No external power source required – simple, low cost installation

  • No user setting needed – "fit and forget solution"

  • Small number of parts – simple maintenance and low cost of ownership

  • Robust design capable of high vibration and shock applications

  • Easy installation, operates in any mounting position

  • Automatic self-sensing control with positive proportional valve action


  • Lubricating oil temperature control

  • Jacket water high temperature (HT)

  • Secondary water low temperature (LT)

  • Heat recover

  • Water saving applications

  • Boiler inlet temperature control

  • Co-generation, cooling towers

  • Temperature mixing or diverting

  • Engine and compressor cooling systems

Temperature ranges:        13-116°C (55-240°F)


Flow Rates: 15 - 400 m3/hr68 - 1750 US gpm

Sizes: 40 - 200 mm1 ½" - 8"

Body Material: Aluminum, bronze, cast iron, ductile iron, carbon steel, stainless steel

Pipe Connections: Threaded: BSP NPT
Flanged: DIN, JIS, ANSI, US Navy

Amot BO-valve model code example:

(See also table in data sheet p. 8)

3BOCB1000100AA: 3'' valve without manual override (BO), cast iron(C), flange PN10 (B), 100°F element  (100), standard element without override with buna N/Nitrile seal(01), leak hole size (0), leak hole number (0, no customer customization (AA)

33BOCB1000100AA: same as above, but with three elements

4BOCB1000100AA: above, but 4'' valve

4BOCB0950100AA: above, but with 95°F element


The valve is supplied with the temperature element assemblies factory-set to the nominal temperature setting. Temperature is sensed at Port A which remains open to Port B (bypass) until the fluid temperature reaches a point 5 - 10°F (3 - 6°C) below the nominal setting. As the temperature continues to rise, the sliding valve moves to close off Port B and open Port C (connected to the cooler or heat exchanger) Port B is fully closed 8 - 10°F (4 - 6°C) above the nominal setting. The valve continually modulates the fluid flow to maintain the nominal temperature. For optimum control the system should be sized so about half the total fluid flow is passing through the cooler at full load.

Download data sheet for the BO-valve (pdf) >>

bottom of page