An important element that affects the smooth operation of a modern heating system is a thermal head for a warm floor. It is used in combination with a valve to mix hot and chilled coolant flows to control the temperature in water circuits.
The whole system is functioning thanks to the mixing unit. This is due to the fact that water comes from the boiler heated up to 90 0 , and the floor surface index should not exceed 40 0 .
The principle of operation of the mixer with a two-way valve
A thermal head with a sensor for underfloor heating is connected to a system with a two-way valve. Hot water is supplied through it from the boiler to the mixing unit.
The sensor determines the temperature of the coolant supplied to the floor heating, and with its large value, the thermal head valve cuts off the flow from the boiler. The circulation will take place along the inner circuit until the water begins to cool. Upon reaching the set minimum value of the temperature of the coolant from the sensor receives a command to supply hot water and it again begins to mix with the return.
The small capacity of the two-way valves provides heating of rooms with an area of not more than 200 m 2 .
High-quality temperature control of underfloor heating
The method consists in mixing hot water coming from the boiler with a cooled coolant returning back to heating. For this, a three-way valve with a thermal head for a warm floor is used. As a result, water with a predetermined temperature is supplied for heating.
The thermal head is connected to the valve stem through the axle box, which locks the input to the point of its connection. At the temperature sensor signal, the stem with two poppet valves moves. In this case, the passage for one flow opens and closes for the other, as a result of which the temperature of the coolant supplied to the heating circuit changes.
Types of temperature sensors
The remote temperature sensor is a can of gas. It is connected to the bellows of the thermal head by a capillary tube. As the temperature rises, the pressure inside the canister increases and is transmitted through the bellows to move the rod, which covers the flow of hot water through the valve. When the air temperature decreases, the flow of coolant increases.
Instead of gas, a paraffin or liquid thermal valve can be used, which is more inertial. The signal is fed to a heating element located in a cylinder with heat-sensitive filler. When heated, paraffin melts and increases in volume. He presses on the piston and he moves the stem with a valve disc. The range of temperature control of the coolant is in the range of 20-40 0 C.
The temperature control of the heating medium occurs in the mixing unit, consisting of a valve, thermal head and pump. Regulation is performed continuously, and mixing of flows is carried out inside the valve.
Management can be done manually by turning the cover of the thermal head with a scale. In position "1" flows are supplied in equal quantities. The adjustment is coarse because the heat consumption for heating is variable. A more precise control is made by a thermal head with an external sensor for a warm floor inside the return manifold. The method is one of the most effective, although expensive in terms of the equipment used.
Quantitative temperature control of underfloor heating
The distribution comb or manifold 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 the given modes. A comb is needed when their number is more than two. The ratio of the heat carrier flows sets on each circuit a thermal head for a warm floor.
The simplest way is to quantitatively control the temperature of the warm floor through changing the flow rate of the coolant. The flow to each circuit is controlled by the RTL thermal head. It maintains the set water temperature at the outlet of each loop. The sensor is a bellows filled with a heat-sensitive fluid. The position of the valve disc depends on its temperature and the setting of the outer cover with a scale.
A thermal head for a warm floor senses the air temperature in the room and, depending on its size and manual settings for maximum heating of the heat carrier. The upper and lower levels of the control range are limited by locking clamps.
The model may have internal or external threads with which it is screwed to the pipe.
How does the thermostatic head work?
The set temperature of the heat carrier is set on the head scale (photo below).
As soon as it is reached (about 40 0 ), the heat-sensitive element begins to put pressure on the valve stem and shut off the flow of hot water. As a result, the coolant in the loop begins to cool. As the temperature decreases, the thermal head begins to release the stem and the passage for fluid increases. The amount of hot water supplied to the circuit increases and the floor surface begins to heat up again.
Thus, the thermostatic valve controls the temperature of the water passing through the floor heating circuit at a constant flow rate. Only the ratio of hot liquid to cooled changes.
Floor heating mode
The mode is selected at the discretion of the residents. The most common is comfortable or heating. In the first embodiment, the surface temperature is maintained at 28-32 0 C. Here, the heating function of the main room is performed by other devices, for example, radiators. The second option involves maintaining a given air temperature in the room, which should provide a warm floor. For this, room thermostats that control heating are used.
How much fluid passes through the circuit is shown by the flowmeter mounted on the supply manifold. A thermal head for a water floor heating is installed on the return manifold.
The pressure in the system is generated by the central circulation pump of the heating boiler. So that he can push through all the loops, the length of each should be no more than 60 m.
Remote thermal head for underfloor heating
In a heated floor system with automatic control of indoor temperature, thermostats associated with the controller are monitored. The remote room thermostat sends a signal to the servo drive, which controls the manifold valve. In addition, the controller has the following functions:
- response to sensor readings, including outside the house;
- organization of heating modes for certain rooms;
- shutdown and inclusion of heating in separate rooms at different times;
- work with remote control via GSM communication.
Automation costs will pay off over time, because it provides an opportunity to save up to 20% of the funds spent on heating.
Choosing a floor heating system
For one small room, you should choose the simplest floor heating scheme 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 underfloor heating is optional, it needs a mixing unit. It consists of a three-way valve, a thermal head and a pump. At high temperature in the house, the return line is closed and internal circulation occurs through the pipes of the warm floor. As soon as the coolant begins to cool, the valve opens again and hot water enters the mixer.
When using a warm floor as the main heating, it is divided into zones, each of which is controlled according to simple schemes. You can equip one large mixing unit for all circuits. Here you will need a controller that sets the temperature limits of the coolant in the rooms.
Conclusion
A thermal head for a warm floor is an essential element in a low-temperature heating system. Together with the thermostatic valve, it is a key element of the system, ensuring efficient use of the coolant and fuel economy. They are both installed when necessary. If you design the right scheme, a warm floor can be installed on your own. The development and installation of a complex system is best entrusted to specialists.