September 10, 2010
With the continuous deepening of coal-to-electricity conversion, air source heat pump heating has been widely used in North China, giving strong impetus to the development of the industry. Heating is a livelihood project. In order to ensure the effect of heating in winter, in addition to the performance of the heat pump itself, on-site installation and construction are also particularly important. Leomon combines several years of project practice experience to share with you the common problems of air source heat pump heating system installation. The following is for your reference and learning.
1. System composition of air source heat pump heating
The air source heat pump heating system mainly includes air source heat pump, heating terminal (fan coil floor heating, radiator heating), pipes, water tanks, pipeline heating system, constant temperature mixing valve, temperature control center and other parts.
The main part of the air source heat pump heating system includes: heat source equipment, i.e. air source heat pump; pipeline accessories and fittings: circulating pipeline water pump, Y-type filter, check valve, butterfly valve, rubber flexible joint, system water supply device, pressure differential bypass valve, pressure gauge and thermometer, exhaust valve, electric control box, etc.
The indoor part is determined according to different terminal forms, including fan coil, fan coil electric two-way valve, floor heating coil, floor heating manifold, radiator, etc.
2. Construction and installation of heat pump heating system
1. Main part
1) Transportation and transportation of air source heat pump. During transportation, the inclination angle of the heat pump should be kept within the range of 75°-105°, and it should not be over-inclined. It is usually transported by electric forklift or crane. If there is no electric forklift and crane, or it is inconvenient to use mechanical transportation, rolling transportation can be used.
Rolling transportation: Place 6 rollers of the same size under the base of the heat pump. Each roller must be longer than the outer frame of the base and suitable for the balance of the heat pump.
2) Construction of the main unit foundation of the air source heat pump. The foundation of the air source heat pump is generally more than 30 centimeters. In Hebei, Henan, Shandong and other places, even if there is thick snow on the road after snowing, it will not interfere with the normal operation of the main unit. However, in the northeast or northwest regions, the height of the foundation needs to be increased, otherwise the thick snow will block the heat pump, and the equipment cannot be used or even frozen. Therefore, the height of the main unit foundation needs to be designed according to the local snowfall.
2. Installation of the water pump
During the installation of the water pump, a rain shelter needs to be built to prevent rainwater from entering the bearing impeller of the water pump and causing damage to the pump body. In addition, if the rain shelter is not installed, the noise of the standby pump will become very loud when it is activated. When the water pump is connected to the bracket, a shock-absorbing pad needs to be installed, otherwise the noise will be very loud during operation. A check valve needs to be installed at the outlet of the water pump, and rubber soft connections need to be installed at the front and rear ends to reduce the noise generated during the operation of the water pump.
3. Heat pump pipe connection
After the air source heat pump is fixed, the water inlet and outlet pipes can be installed to determine the direction of the pipes; according to the technical parameters of the heat pump, select the appropriate water pump and pipes to eliminate heat pump failures caused by inappropriate accessory specifications; do not leave other debris in the pipes during the connection process; connect the pipes according to the design schematic diagram, and construct according to relevant national technical standards so that the heat pump can be maintained and maintained during use; the water pipes should be installed horizontally and vertically, the pipes should be arranged reasonably, and the bends should be minimized to reduce the resistance of the water system; after the installation of the tap water supply pipe, the connecting pipe between the host and the water tank, a strict water pressure test should be carried out and the sewage should be discharged to ensure the cleanliness of the system; the water supply/circulation pipe must be wrapped with thermal insulation materials.
When installing the pressure gauge, it is necessary to install valves and buffer components (bends) to facilitate later maintenance and replacement, and at the same time extend the service life of the pressure gauge; when connecting the pipe to the host, it is also necessary to install a stainless steel hose, and a filter needs to be installed at the water inlet. In order to save costs, some people use inferior rubber soft connections, which will affect the service life of the entire system.
4. Water system pressure maintenance
After the water system connection pipeline is installed, a water pressure test is carried out, and the accuracy of the pressure gauge should be greater than 0.01Mpa; during the water system water pressure test, when the working pressure is less than or equal to 1.0Mpa, it is 1.5 times the working pressure, but the minimum shall not be less than 0.6Mpa. When the working pressure is greater than 1.0Mpa, it is the working pressure plus 0.5Mpa.
When maintaining pressure, it is necessary to disconnect from the host. If the pressure is maintained together with the host, the parts on the air source heat pump side will be damaged; when filling the water system with water, the exhaust valve must be opened, and the air must be exhausted and then closed after the water is full; if there is a leak during the pressure maintenance process, it must be repaired immediately, and the pressure maintenance test must be repeated again.
5. Water system cleaning
After the water system connection pipeline is installed, the water system must be cleaned. When cleaning, it must be separated from the host, and the water system must be circulated and cleaned separately. After ensuring that the water system is free of impurities, the water system can be connected to the host.
The Y-type filter is an auxiliary component close to the host and is located at the water inlet pipe of the heat pump. When cleaning, you can use a high-density filter for multiple cycles of cleaning to remove impurities such as particulate matter in the water system.
After the impurities in the water system are filtered out, the dirty water in the system must be replaced. The number of water changes depends on the cleanliness of the water quality of the water system.
6. Water system antifreeze
During all winter project installations, switch to system water replenishment before the air source heat pump has normal antifreeze protection capabilities to prevent freezing and freezing of water pipes and water-side heat exchangers; antifreeze can be added to the system to prevent freezing of the heat pump in winter. If you add, please refer to the instruction manual for details.
7. Insulation and anti-corrosion
The pipes and equipment foundation supports and hangers must be treated with anti-corrosion, and anti-rust paint should be applied after rust removal. Threaded connection is recommended for steel pipes less than or equal to DN65. When the pipe diameter is greater than or equal to DN80 and is not convenient for threaded connection, welding can be used, but the weld needs to be painted with anti-rust paint. The inner and outer surfaces of the water tank need to be treated with anti-corrosion, or anti-corrosion materials are used. Polyurethane foam insulation is used between the inner and outer walls of the water tank, and the insulation thickness is at least 50mm. Air conditioning water pipes must be insulated, with outdoor insulation thickness of at least 30mm, and the insulation materials must comply with national standards.
