An important element that affects the smooth operation of a modern heating system is a thermal head for underfloor heating. It is used in combination with a valve for mixing hot and cooled coolant flows in order to control the temperature in water circuits.
The whole system functions thanks to the mixing unit. This is due to the fact that water from the boiler comes heated to 900C, and the floor surface index should not exceed 400C.
The principle of operation of the mixer with two-way valve
Thermo 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 heat carrier supplied to the floor heating, and if it is high, the thermal head valve cuts off the supply from the boiler. Circulation will occur along the internal circuit until the water begins to cool. Upon reaching the specified minimumthe 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 throughput of two-way valves provides heating for rooms with an area of \u200b\u200bno more than 200 m22.
Quality regulation of the temperature of the warm floor
The method consists in mixing hot water coming from the boiler with the cooled coolant returning back to the heating. For this, a three-way valve with a thermal head for underfloor heating is used. As a result, water with a given temperature is supplied for heating.
The thermal head is connected to the valve stem through a bushing blocking the entrance to the place of its connection. At the signal of the temperature sensor, the stem with two poppet valves moves. In this case, the passage for one stream opens, and for the other it closes, as a result of which the temperature of the coolant supplied to the heating circuit changes.
Types of temperature sensors
Remote temperature sensor is a gas canister. It is connected to the thermal head bellows by a capillary tube. When the temperature rises, the pressure inside the cartridge increases and is transmitted through the bellows to the movement of the stem, which covers the supply of hot water through the valve. When the air temperature drops, the coolant supply increases.
Instead of a gas valve, a paraffin or liquid thermal valve, which are more inertial, can be used. The signal is sent toa heating element located in a cylinder with a heat-sensitive filler. When heated, the paraffin melts and increases in volume. It presses on the piston and it moves the valve stem with the valve disc. The heat carrier temperature control range is within 20-400С.
The temperature of the heating medium is controlled in the mixing unit, which consists of a valve, a thermal head and a pump. The regulation is continuous and the mixing takes place inside the valve.
Management can be done manually by turning the thermal head cover with a scale. In position "1" the flows are supplied in the same quantities. The adjustment is rough, since the heat consumption for heating is a variable. More precise control is performed by a thermal head with a remote sensor for underfloor heating, located inside the return manifold. The method is one of the most effective, although expensive for the equipment used.
Quantitative regulation of underfloor heating
The distribution comb or collector is a node 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 specified modes. A comb is needed when their number is more than two. The ratio of coolant flows is set on each circuit by a thermal head for underfloor heating.
Quantitative regulation is the easiest waytemperature of the warm floor, through a change in the flow rate of the coolant. The flow to each circuit is controlled by a thermal head for RTL underfloor heating. It maintains the set water temperature at the outlet of each loop. The sensor is a bellows filled with a temperature-sensitive liquid. The position of the valve disc depends on its temperature and the setting of the outer cover with a scale.
Thermohead for underfloor heating perceives the air temperature in the room and, depending on its value and manual adjustment of the maximum heating of the coolant. The upper and lower levels of the adjustment range are limited by the locking clips.
The model can have internal or external threads, with which it is screwed to the pipe.
How does a thermostatic head work?
The set coolant temperature is set on the head scale (photo below).
As soon as it is reached (about 400С), the thermosensitive element begins 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 drops, the thermal head begins to release the stem and the fluid passage increases. The amount of hot water supplied to the circuit increases and the floor surface begins to heat up again.
Thus, the thermostatic valve regulates the temperature of the water passing through the underfloor heating circuit at a constant flow rate. Only the ratio of hot liquid and cooled liquid changes.
Floor heating mode
The mode is selected onresidents' discretion. The most common is comfort or heating. In the first variant, the surface temperature is maintained at the level of 28-320С. Here, the function of heating the main room is performed by other devices, for example, radiators. The second option involves maintaining the set air temperature in the room, which should provide a warm floor. To do this, use room thermostats that control heating.
How much liquid passes through the circuit is shown by a rotameter mounted on the supply manifold. The thermal head for a water heated floor is installed on the return manifold.
The pressure in the system is created 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 floor heating
In a floor heating system with automatic control, the temperature in the rooms is monitored by thermostats connected to the controller. The remote room thermostat sends a signal to the servomotor that controls the manifold valve. In addition, the controller has the following functions:
- reacting to sensor readings, including outside the house;
- organization of heating modes for certain rooms;
- off and on heating in separate rooms at different times;
- work with remote control via GSM connection.
The cost of automation will pay off over time as it enablessave up to 20% on heating bills.
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 temperature of the water 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 a warm floor is additional, a mixing unit is required for it. It consists of a three-way valve, a thermal head and a pump. At high temperatures in the house, the return flow is blocked and internal circulation occurs through the pipes of the warm floor. As soon as the coolant begins to cool, the valve will open again and hot water will flow into 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. It is possible to equip one large mixing unit for all circuits. Here you will need a controller that sets the temperature limits for the coolant in the rooms.
Conclusion
Thermohead for underfloor heating is a necessary element in the 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. Both of them are installed when necessary. If you design the right scheme, you can install a warm floor on your own. Development and installationa complex system is best left to specialists.
