Brand classification of wall-hung boiler:
Wall-hung boilers are divided into two categories: imported and domestic joint ventures.
Original imports are divided into regional brands such as Germany, Italy, France and South Korea. Domestic joint ventures are divided into assembly plants and joint ventures.
1, German brand: Weineng, wiesmann, Doctor.
2. Italian brands: The original imported brands are Faruoli, Yima, Beretta and Baxi, which are divided by the heating method of domestic hot water. There are two main types of wall-hung boilers: thermal type and volumetric type, and thermal type is divided into sleeve type and plate-changing type.
Like the brand I know, Faruoli Liu Hui Saddle Notification Heat Exchanger has won the world patent and the highest achievement award in Europe. German Weineng is a board-changing type, and Bosch has both. There is a big difference between the two models, so it is best to choose the model first and then the brand.
Heat exchange classification of wall-hung boilers: ① ordinary sleeve type; ② Double heat exchanger type; ③ Farrow-Hui-Hui Saddle informs the type of heat exchanger; 1. heat exchange principle:
The double-tube heat exchanger is a double-tube heat exchanger. The domestic hot water sleeve is nested in the main heat exchanger, and the priority operation of domestic hot water is controlled by the start and stop of the pump. When the domestic hot water is running, the pump stops working, and the domestic hot water in the casing is heated by the first-class high-temperature water in the main heat exchanger.
Plate heat exchange type is to heat domestic hot water through plate heat exchanger, and the priority operation of domestic hot water is completed by electric three-way valve. When there is a demand for domestic hot water, the electric three-way valve introduces the primary high-temperature water in the main heat exchanger into the plate heat exchanger to heat the domestic hot water.
Second, the technical comparison:
1, comfortable hot water for living.
In the process of using domestic hot water, when the user temporarily turns off the production hot water and turns it on for a short time, because the water in the main heater does not flow, the residual heat of the main heat exchanger and the first-class high-temperature water will continue to heat the domestic hot water in the sleeve. At this time, when the domestic hot water is turned on, a section of high-temperature water will appear, causing the domestic hot water to be hot and cold, even scalding the user.
Plate heat exchange can completely avoid this problem, and it is safe and comfortable to use domestic hot water.
2. Scaling ratio
During heating operation, the first-class high-temperature water will continuously heat the domestic hot water in the shell, resulting in high-temperature scaling; When domestic hot water is used or temporarily stopped, because the water in the main heater does not flow, the residual heat of the main heat exchanger and the first-class high-temperature water will continue to heat the domestic hot water in the shell, which will also cause high-temperature scaling. With the increase of service time, the scale will become thicker and thicker, which will affect the efficiency of wall-hung boilers, especially in areas with hard water quality.
Generally, the water temperature on the water side is below 60℃ (the actual water temperature is below 50℃), and it is not easy to scale below 60℃, so it is convenient to remove, clean and replace the plate.
3, service life
When the domestic hot water is used up or temporarily stopped, because the water in the main heater does not flow, the residual heat of the main heat exchanger cannot be taken away in time, resulting in local high temperature and affecting the service life.
Plate heat exchange heat exchange form When the domestic hot water ends, the water pump will run for a period of time, which can effectively avoid local high temperature.
Third, the structure and price comparison:
The casing machine has no electric three-way valve and no separate domestic hot water heat exchanger, so the structure and control are simple and the price is relatively cheap.
Due to the addition of domestic hot water plate changer and electric three-way valve, there are relatively many internal parts of the plate changer, which is expensive.
The casing machine is generally called economical, and the plate changer is called comfortable. For example, Bosch's Eurostar has two series: economical ZWE(E is economy) and comfortable ZWC (c: comfort).
Fourth, product model comparison:
The casing machine is easy to scale, and the double heat exchanger is easy to use two heat exchangers in the system. The system must be equipped with a three-way reversing valve to switch between heating and domestic hot water. The three-way reversing valve is easy to close without aging, which makes the two thermal systems interpenetrate and increases the fault point. Whether it is dead warm or domestic hot water, the circulating water pump should be in working mode, increasing energy consumption and reducing service life.