What is a backwater system? Is it necessary to install the home decoration?

Hot water backwater system: refers to the backwater pipeline system on the outlet pipe of the water heater, which aims to circularly heat the water in the hot water pipeline from the water heater to the faucet. Because the hot water pipe between the water heater and the faucet has no heat preservation function, the hot water in the pipe will get cold after a long time. When the tap turns on hot water, the cold water in the hot water pipe must be drained before the hot water will flow out. This brings two problems: first, it wastes water resources; Second, it is inconvenient to use hot water, and you have to wait for several seconds, ten seconds or even longer every time.

Common hot water return system includes thermostat, return pipe and one-way check valve. The thermostat controls the backwater circulation system. When it is detected that the water temperature in the hot water pipe is low, the circulating pump is started to convey the cold water in the hot water pipe to the water inlet pipe (cold water pipe) of the water heater, and the water heater starts to heat, and when the water temperature in the hot water pipe reaches the normal set temperature, the circulation is stopped. Return pipe is installed on the hot water pipe, usually arranged together with the hot water pipe, and the end of the hot water pipe (hot water pipe in front of the faucet) is connected with the water inlet of the water heater. Install a check valve on the return pipe at the end of the hot water pipe to prevent return pipe cold water from reversely entering the hot water pipe.

Advantages and disadvantages of hot water reflux system: the advantage is that it can ensure the convenience of using hot water at the faucet, and the hot water can be discharged as soon as possible without waiting for a long time, and at the same time avoid wasting cold water in the hot water pipe when using hot water. The disadvantage is that the installation cost is increased, and it is necessary to buy a backwater device (about 800-2,000 yuan), a one-way valve (30-50 yuan) and an extra water pipe (about 200-500 yuan); In addition, after the backwater system is installed on the hot water pipe, it is kept in a normally open state. As long as the system detects that the temperature in the pipeline is low, it will start the circulating pump of the water heater for heating, which will waste energy unless you have the need to use hot water 24 hours a day. If the backwater system is turned on only when hot water is used, it is usually closed, which is not very convenient and has no effect of immediate heating. After the backwater system is turned on, the water in the pipeline should be heated for several minutes, which has the advantage of not wasting water.

Whether it is necessary to install a hot water return system depends on your own hot water demand and use location:

1. First, calculate how much water is wasted according to the length of the water pipe-take DN25 (Branch 6), a commonly used PPR water pipe at home, as an example. 3. 18 meter long water pipe contains 1 liter water, and 6 meter long hot water pipe wastes about 1.8 liter water each time. The calculation method is to calculate the hollow cross-sectional area in the pipe and then multiply it by the length of the pipe to get the volume, and then convert it into units (1L= 1000 cubic centimeter). The cross-sectional area is calculated by multiplying the inner diameter of the tube (the diameter of the outer wall of the tube minus the thickness of the tube and dividing it by two to calculate the radius) by the inner diameter of the tube and then by 3. 14. Is it acceptable or usable, such as kitchen sink, sanitary indirect mop bucket and toilet.

2. If the distance is far, it is recommended to install a backwater system, for example, if it is more than 8 meters or the cold water in the pipe is more than 2L, if it is close, it is not necessary to install it. Because the cost of backwater system is equal to the price of a large electric water heater and several small electric water heaters, it is better to install a small water heater at a short distance. For example, kitchen treasures are used in the kitchen and large water heaters are used in the bathroom.

3. It is generally not recommended to install a hot water return system, because most people use water heaters that consume electricity or use natural gas, and the return system consumes more energy. Unless a large water heater with low energy consumption is installed, such as solar energy, air energy water heater, ground source heat pump and other environmentally friendly and economical energy sources, installing a hot water reflux system is low in energy consumption, water saving and convenient to use. If electric heating, natural gas and other consumable paid energy sources are used, it is inconvenient and energy-saving to install the backwater system, so it is better to install more water heaters.

Whether the hot water pipe backwater system is installed or not needs to consider economy, practicality, maintenance convenience and energy saving.

Some suggestions on hot water pipes during decoration

1, the best way to do water pipe insulation, which is beneficial to energy saving. Choose thick-walled hot water pipes.

The shorter the hot water pipe, the better. The longer the water pipe is, the more the water temperature drops from the water heater to the faucet, resulting in too high water temperature setting and wasting energy. So try not to detour when designing the pipeline.

3, hot water pipes buy special hot water pipes, can not be replaced by cold water pipes.