RLC thermostat - classification and detailed explanation of floor heating thermostat

1. Mechanical

The sensitive gas diaphragm box or thermal bimetal sheet is used as the temperature sensing element to form the temperature control switch of the mechanical contact. This kind of thermostat is more in the European and American markets, and only a few domestic manufacturers promote such products. Mechanical floor heating thermostats usually have a contact current of no more than 8A, which is suitable for the opening and closing of control valves in water heating systems. Its advantages lie in low cost, simple installation and use, and good long-term reliability; The disadvantages are that the temperature control switch deviation is large (generally greater than ±3 °C), the display is not intuitive enough, and the function is relatively simple; The output contact current is only 8A, which also limits its application in electric heating engineering.

2. Electronic

The temperature sensing element is a thermistor (NTC) with a negative temperature coefficient, and the relay contact controls the output. According to the size of the contact current, the conventional specifications are 3A, 5A, 8A, 16A, which can meet the control requirements of water heating system and electric heating system with large load (below 3500W). It has the advantages of low cost, simple operation and high temperature control accuracy (±1°C). In terms of function, it is superior to mechanical thermostats, such as the installation position of the temperature sensor can be diversified, with built-in (with the product panel inside) and external (external ground probe) or both built-in temperature control and external temperature limiting; Individual brand products also have energy-saving programming function, only need to add a time control programmer of about 100 yuan, and connect the energy-saving control points of dozens of thermostats in the same area to the time control programmer, you can achieve reasonable energy-saving control. When you're not at home, the set temperature is automatically lowered by 5°C.

The electronic thermostat continues all the advantages of the mechanical thermostat, greatly improves the shortcomings of the mechanical thermostat in terms of function, and the degree of intelligent control basically meets all applications. Therefore, it is widely used in China, especially for children and the elderly. Due to its simple operation and good long-term reliability, it is also favored by many rational "minimalist" young families.

3. LCD display type

The liquid crystal display thermostat has been applied in the floor heating system, which fully reflects the intelligent, automated and personalized consumption concept of the floor heating system. The popularity in China is much higher than that of European and United States countries, so in China there are various forms, varieties, and uneven quality. The advantages of liquid crystal display floor heating thermostat must be well known to all experts, this article will not be discussed, in this chapter we are more willing to analyze the current situation of liquid crystal display floor heating thermostat in China, so as to refer to the selection.

4. In the early days of LCD floor heating thermostats, it is not difficult to find that most manufacturers directly modify the central air conditioning coil thermostats, which are prone to many problems. As:

1) The LCD interface is too large or the display symbols are not proportional or standard.

2) The terminal blocks or circuits (components) that control the output cannot withstand large currents.

3) The cable of the external sensor (ground probe) is a thin and flexible wire, which cannot be inserted into the embedded pipe, and it is also a hidden danger for future maintenance.

4) The control logic does not match the requirements of the floor heating system, resulting in the function is not dedicated and practical.

5) There is only one temperature control circuit, which cannot achieve "internal control and outer limit". That is, it is impossible to measure and control the air temperature in the room, and at the same time, it is limited to the ground temperature.

6) The overall shape is thin and the structure is unreasonable. The failure rate of the initial adjustment of the installation is higher, and the long-term stability is worse.2.3.2 Low price vicious competition, weak brand awareness, extremely high failure rate, and almost zero terminal technical service. As a direct result, some users would rather buy European and American products at several times the price.

There is no unified industry or national standard for products, and there is no recognized basis for production and acceptance. Note: We have consulted with relevant national agencies on this issue, and suggested that the floor heating thermostat be included in the scope of national CCC compulsory certification of electrical products, and strive to solve the problem as soon as possible.

5. Weekly programming period to control the floor heating thermostat

The weekly programming period control floor heating thermostat is one of the liquid crystal display floor heating thermostats. With a weekly cycle, 6 periods and the corresponding set temperature can be set every day, and it can be changed to manual or temporary control operation mode. The following table lists a more common factory default time setting parameter: the weekly programming period control method is another energy-saving revolution in heating automatic control. It not only ensures comfort, but also reflects energy saving, environmental protection and health. And it has many personalized functions, such as: the selection of working mode (single or double break, no break), pre-heating in advance, energy consumption monitoring, key lock and other functions. According to our experiments, the correct use of the time-controlled thermostat will save more than 30% of energy (compared with the non-time-controlled thermostat), in fact, the increased investment can be recovered within one year. For example, in cities with peak and valley electricity prices, the application of energy saving in electric heating systems is more significant.

6. Wireless control floor heating thermostat

Using radio frequency wireless 433MHz transmission, there are mature products in foreign countries but few applications, and they are rarely used in China. Wireless control thermostat is limited by factors such as installation distance, poor reception stability, high cost, and short battery life; In addition, China is basically a new property, and the wiring (wired) is very convenient when it is first installed; Therefore, there is basically no market demand at this stage.

7. Remote (centralized) control of the thermostat

Small systems generally use the Internet, fixed-line communication, and GPRS to implement remote monitoring. At present, the more typical application examples are: telephone remote control, residents use telephones, mobile phones to monitor or set their own thermostat switching time, set temperature, etc.

Large-scale systems are used in large buildings, with control points ranging from a few hundred to a few thousand, to achieve centralized control of the terminal area. Using computer network technology and microcomputer software, the operation of the entire system is monitored, analyzed, managed and recorded in the control room. The application of remote (centralized) control technology to the floor heating temperature control system is rarely implemented abroad, and there have been examples of application in China. The author believes that it is necessary to be cautious before choosing.

RLC thermostat - classification and detailed explanation of floor heating thermostat

RLC thermostat - classification and detailed explanation of floor heating thermostat

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