In the past two years, with the upgrading of consumption in the south, the air source heat pump cooling and heating unit has big market, The fundamental reason for the huge changes in the market is that consumers’ demand for heating and cooling has been upgraded from functional demand to comfort demand. Driven by the overall consumption upgrade, the cooling-heating air source heat pump has been favored by more and more consumers because of its outstanding advantages in comfort, energy saving and environmental protection. The market for heat pump cooling heating unit scale is developing rapidly at a growth rate of more than 200%.
Compared with wall-hung boiler heating system, the air source heat pump cooling heating system installation has a higher technical threshold. In practical applications, there are also various problems, which make many dealers daunting. The following experience is for your reference!
System install buffer tank will be more energy efficient.
In addition to the functions of heat storage and balance system stability, the buffer tank also has functions such as exhaust and sewage.
| Buffer tank model choice | ||
| Heating capacity kW | Expansion tank L | Installation require |
| <20 | 60 | Install by the return water pipe side, inlet higher outlet lower, above install discharge valve |
| 20 to 45 | 100 | |
| 45 to 70 | 200 | |
| 70 to 130 | 300 | |
Besides buffer tank, an expansion tank is also needed for cooling-heating system installation.
As long as an open or closed water circulation system with water pump, no matter whether there is a buffer tank or not, an expansion tank or a high-level expansion tank must be used. Expansion tank not only digests thermal expansion of water, but also has an important function of “constant pressure”, so expansion tank is also called constant pressure tank. If the expansion tank is not installed or the model selection is incorrect, there will definitely be frequent accumulation of air and unclean exhaust. Many water system failures frequently appear, which may be caused by unscientific partial installation.
| Expansion tank model choice | ||
| Heating capacity kW | Expansion tank L | Accessories |
| <12.5 | 5 | Automatic water supply valve Pressure relief valve |
| 12.5 to 25 | 8 | |
| 24 to 45 | 12 | |
| 45 to 75 | 19 | |
| 75 to 112.5 | 24 | |
| 112.5 to 150 | 36 | |
Note: ①It is better to choose 304 stainless steel flange for expansion tank, carbon steel galvanized is easier to rust.
②The pre-charge pressure of the expansion tank is equal to the set pressure of the water make-up valve.
③It is recommended to check the inflation pressure of the expansion tank every 1-2 years, and inflate when the pressure is low.
Install an automatic exhaust valve at the highest point of the system.
If the location of the water tank for the heat pump cooling-heating system installation is hard to determine, we have to determine it according to the on-site situation. However, in some cases, it can only be installed on the ground or lower places, then the exhaust problem must be considered in the system.
If the water tank is installed higher than the system pipeline, an automatic exhaust valve can be installed on the top of the water tank, because the fan coil and the floor heating pipes has a manual exhaust valve.
If the position of the water tank is lower than the system pipeline, in addition to the buffer tank must be equipped with an automatic exhaust valve, the system’s water inlet and return pipe also need to be equipped with an automatic exhaust valve at the highest point, otherwise if the pipeline enters air, it will increase water resistance, in severe cases, it will cause air blockage in the water circuit and block circulation.
Some people would say, isn’t the system under pressure, how can the air get in? Because in winter, when the floor heating is used for heating, some air in the water will be released.
The system main pipe must be straight laid.
The main pipe of the whole system must be straight. It is best to have a slight upward slope along the direction of the water flow. The inlet pipe is slightly lifted up, and the return pipe is slightly lowered. This can facilitate the discharge air in the pipe, and the main pipe must not be U-shaped, It will form a gas block, even if the soft connection is used.