How does a thermostatic balancing valve work?
April 29, 2020

How does a thermostatic balancing valve work?

A thermostatic balancing valve has a sealed thermostatic "motor" in the flowstream of the valve body, which responds to temperature to open and close the valve to control water flow. The thermostat expands when heated which drives the valve seat toward closed, and contracts on falling temperature to open the valve seat. The linear action of the motor is calibrated with an opposing spring to control the stroke of the valve stem. Thermostatic balancing valve seats do not close completely; they must allow some water to flow across the thermostat so it can respond to changing inlet temperatures.

Caleffi's 116 Series ThermoSetter is a brand new, technologically advanced adjustable thermostatic balancing valve; the setpoint knob changes the spring tension for the thermostat which in turn changes the open/close setting of the thermostatic and valve seat. The ThermoSetter also has an optional temperature gauge and a choice of integral second cartridges for systems that implement thermal disinfection cycles for Legionella control. Check out all the 116 Series information on Caleffi's website!

Thermostatic balancing valves are relatively new choice for hot water recirculation circuits, compared to manual (a.k.a. pressure dependent or static) balancing valves and automatic (a.k.a. pressure independent or dynamic) balancing valves. Each type have their place, with varieties of features & benefits, and price point. Caleffi manufactures all types, such as our 142 Series and 130 Series Manual Balancing Valves, our 127 Series and 121 Series Automatic Balancing Valves, and our totally unique 132 Series QuickSetter. Contact us for more details on these too; we'll be glad to help.


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Blog post comments
Joe London
May 01, 2020

Been using CircuitSolvers for years. How does your valve address scale? We've experienced issues...especially hard water applications.


In reply to by Joe London

May 04, 2020

I think you will find that every product is effected by water quality.  The advantage that our 116 Thermosetter has is that it is easy to disassemble, clean and reassemble.  It is more serviceable and easier to maintain than any of our competitors.   You will find the maintenance instructions here in the installation manual on page 10.  

Kevin McKenzie
January 21, 2021

I have a seal that is leaking in my "Dynamic Balancing Valve" Series 127, where do I get replacement seals?

January 25, 2021

Kevin, If you're looking for a replacement union washer you can find that through wholesale distribution or online under Caleffi part number R20011. If you need further assistance please email:

Imran Khan
October 23, 2021

I want to know that, How the circulation of water will work with balancing valve.

October 28, 2021

The 116 ThermoSetter will modulate the flow rate based on the temperature of the water passing through it.  It is adjustable and once desired water temperature is set it will open to allow a higher flow rate until the desired temperature is achieved and then close down to a minimum flow to continue to monitor temperature and push the remaining system flow to other circuits thus providing balancing based on temperature.  These work well when paired with a variable Delta P pump.