Thermal head for underfloor heating: description and photo

An important element affecting the smooth operation of a modern heating system is the thermal head for the warm floor. It is used in combination with a valve for mixing hot and cooled heat transfer streams in order to regulate the temperature in the water circuits.

The whole system functions thanks to the mixing unit. This is due to the fact that water is heated from the boiler to 90 ⁰ C, and the floor surface indicator should not exceed 40 ⁰ С.

The principle of the mixer with a two-way valve

The thermal head with a sensor for the warm floor is connected to a system with a two-way valve. Hot water from the boiler is fed through it into the mixing unit.

The sensor detects the temperature of the heating medium supplied to the floor heating, and at its high value, the thermal head valve cuts off the supply from the boiler. Circulation will take place along the inner contour, until the water begins to cool down. When the specified minimum value of the coolant temperature is reached, the sensor receives a command to supply hot water and it starts mixing again with the return water.

A small capacity of two-way valves ensures heating of rooms with an area of no more than 200 m ² .

Quality control of the temperature of the warm floor

The method consists in mixing the hot water coming from the boiler with the cooled coolant returning to the heating. For this, a three-way valve with a thermal head for a warm floor is used. As a result, water is supplied at a set temperature for heating.

The thermal head is connected to the valve stem through an axle blocking the entrance to the place of its connection. On the signal from the temperature sensor, the rod with the two disk valves is moved. At the same time, the passage for one flow is opened, and for the other, it closes, as a result of which the temperature of the heat carrier fed to the heating circuit changes.

Types of temperature sensors

The remote temperature sensor is a can of gas. It is connected to the thermo head with a capillary tube. As the temperature increases, the pressure inside the canister increases and is transmitted through the bellows to the movement of the rod, which covers the supply of hot water through the valve. When the air temperature decreases, the supply of coolant increases.

Instead of gas, a paraffin or liquid thermal valve can be used, which is more inertial. The signal is applied to a heating element located in a cylinder with a thermosensitive filler. When heated, wax melts and increases in volume. He presses the piston and he moves the stem with the valve plate. The range of control of the temperature of the coolant is in the range of 20-40 ⁰ С.

The temperature control of the heating medium takes place in a mixing unit consisting of a valve, a thermal head and a pump. Regulation is carried out continuously, and mixing of flows is carried out inside the valve.

Control can be done manually, by turning the cover of the thermal head with a scale. In the "1" position, the flows are supplied in equal amounts. The adjustment is rough, since the heat consumption for heating is variable. A more accurate control is produced by the thermal head with a remote sensor for the warm floor inside the return collector. The method is one of the most effective, albeit expensive for the equipment used.

Quantitative regulation of the temperature of the warm floor

The distribution manifold or collector is a unit that ensures the correct operation of the underfloor heating system. In this case, the coolant is distributed along the contours not necessarily evenly, but according to predetermined regimes. A comb is needed in case their number is more than two. The ratio of coolant flows establishes a thermal head for each floor for a warm floor.

The simplest method is the quantitative regulation of the temperature of the warm floor, through a change in the flow rate of the coolant. The flow for each circuit is controlled by the thermal head for the warm floor RTL. It maintains the set water temperature at the output of each loop. The sensor is a bellows filled with a thermosensitive fluid. The position of the valve plate depends on its temperature and the setting of the outer cover with the scale.

Thermal head for the warm floor perceives the temperature of the air in the room and, depending on its size and manual adjustment of the maximum heating of the coolant. The upper and lower levels of the control range are limited by the locking clamps.

The model can have an internal or external thread, by means of which it is screwed to the pipe.

How does the thermostatic head work?

The set coolant temperature is set on the head scale (photo below).

As soon as it is reached (around 40 ^° C), the thermosensitive element starts to press on the valve stem and shut off the flow of hot water. As a result, the coolant in the loop begins to cool down. When the temperature decreases, the thermal head begins to release the rod and the fluid passage increases. The amount of hot water supplied to the circuit increases and the floor surface starts to heat up again.

Thus, the thermostatic valve regulates the temperature of the water passing through the contour of the warm floor at a constant flow rate. Only the ratio of the hot liquid to the cooled liquid is changed.

Floor heating mode

The regime is chosen at the discretion of the tenants. The most common is comfort or heating. In the first variant, the surface temperature is maintained at 28-32 ^° C. Here, the heating function of the main room is performed by other devices, for example, radiators. The second option is to maintain the desired room air temperature, which must provide a warm floor. For this, room thermostats that control heating are used.

How much fluid passes through the circuit shows the rotameter installed on the supply manifold. The thermal head for the water-heated floor is installed on the return manifold.

The pressure in the system creates a central circulation pump for the heating boiler. So that he can press all the loops, the length of each should not be more than 60 m.

Remote thermal head for underfloor heating

In the system of the warm floor with automatic control over the temperature of the air in the rooms, the thermostats associated with the controller are monitored. The remote room thermostat sends a signal to the servo, which controls the manifold valve. In addition, the controller has the following functions:

• Response to the readings of sensors, including outside the house;
• Organization of heating regimes for certain premises;
• Switching off and switching on of heating in separate rooms at different times;
• Work with remote control via GSM communication.

The cost of automation will pay off in due course, as it enables you to save up to 20% of the money spent on heating.

Choice of underfloor heating system

For one small room, you should choose the simplest scheme of a warm floor with two shut-off valves and a valve with a built-in thermostat. The maximum water temperature in the circuit is manually set and the thermostatic head will control the valve depending on the room temperature.

If the house is equipped with a radiator circuit, and the warm floor is an additional one, it needs a mixing unit. It consists of a three-way valve, a thermal head and a pump. At a high temperature in the house, the return flow is blocked and the internal circulation takes place through the pipes of the warm floor. Once the coolant starts to cool, the valve will re-open and hot water will flow into the mixer.

When using a warm floor as a basic heating, it is divided into zones, each of which is controlled by simple schemes. You can equip one large mixing unit for all circuits. Here you need a controller that sets the temperature limits of the coolant through the rooms.

Conclusion

Thermal head for a warm floor is a necessary element in a low-temperature heating system. Together with the thermostatic valve, it is the key element of the system, ensuring efficient use of the coolant and saving fuel. They are both set when there is a need. If you design the right circuit, the warm floor can be installed on its own. It is better to entrust the development and installation of a complex system to specialists.