Thermostatic valve with presetting - how does it work and what is it used for?

A thermostatic valve with a thermostatic head is responsible for regulating the room temperature and ensuring stable operation of the heating system. When the temperature reaches the set value, the thermostatic head closes the valve, limiting the flow of hot water to the radiator. When the temperature drops, the head reopens the thermostatic valve, increasing the flow of the heating medium.

In addition to setting the desired temperature on the head, the preset of the thermostatic valve for the radiator is also important. It is this setting that allows for precise adjustment of the maximum water flow through the radiator, which is crucial for heating comfort and economy.

Why are thermostatic valves with preset settings used?

In practice, central heating systems are not “perfectly balanced.” Longer branches of the heating system (leading to more distant radiators) have greater hydraulic resistance than shorter sections closer to the boiler or manifold. Without proper regulation, this can cause radiators closer to the heat source to overheat, while those further away remain underheated.

A thermostatic valve with a preset setting allows you to balance these differences by adjusting the flow to individual radiators:

the farthest radiator should usually have a more “open” setting (higher flow),

radiators closer to the boiler should have a lower setting (reduced flow),

for radiators of different sizes: a larger radiator usually requires a higher setting, and a smaller one—a lower one.

The result? Better hydraulic balancing of the heating system, even heating, and lower energy losses.

How does the preset setting work in a thermostatic valve?

The preset setting controls the restriction (or increase) of the maximum hot water flow through the radiator thermostatic valve. Modern designs typically feature 5–8 preset positions.

A lower setting means a lower flow rate (greater restriction).

Setting it to a higher value means greater flow (less throttling).

It is worth remembering that the system operates like a system of communicating vessels: reducing the flow on one radiator may increase the flow in other parts of the system. Therefore, any change to the preset should be carefully considered—especially in systems with multiple radiators.

Advantages of thermostatic valves with preset settings

The use of thermostatic valves with preset adjustment offers specific benefits:

lower heat energy consumption thanks to more stable regulation,

lower electricity consumption by the circulation pump (in practice, savings can be noticeable, especially with modern pumps and a well-adjusted system),

more precise room temperature control,

greater comfort and fewer issues such as noise, uneven heating, or “drafts.”

For which systems are pre-set valves suitable?

Preset thermostatic valves are most commonly designed for closed-loop heating systems with a circulation pump , where precise control and flow balancing have a real impact on the operation of the entire system.

On the other hand, valves without a preset (with lower flow resistance) are often used in simpler systems, such as older setups with characteristics similar to gravity-fed systems.

FERRO’s Offering – Thermostatic Valves for Radiators

Ferro thermostatic valves are designed for stable operation in central heating systems. They feature a maximum static pressure of 1 MPa (10 bar) and a maximum operating temperature of 100°C. The models are designed for installation with a thermostatic head featuring an M30x1.5 thread, and the manufacturer provides a 10-year warranty.

FERRO offers various types of thermostatic valves , and adjusting the preset temperature is simple and usually does not require specialized tools. Most often, all you need to do is:

remove the protective cap or head,

set the preset according to the scale (e.g., with a flat wrench),

reinstall the head – after installation, the adjustment mechanism is usually hidden from view.

You can find solutions and product variants at ferro.pl.