Circulating pump requirements for heat pump water heaters

At present, the hot water produced by domestic heat pump water heaters is directly used as domestic water, and the quality of hot water will be related to the health of users. In addition, the tap water quality in China when choosing circulating water pumps is also a key factor that can not be ignored. Therefore, not all shielded pumps on the market are suitable for use as circulating pumps for heat pump water heaters. Health requirements: According to GBT23137-2008 "Household and Similar Purpose Heat Pump Water Heater" 5.1.2 requirements: In the premise of the inlet water quality in line with national requirements, all heat source water side of the pipeline, heat exchange equipment should have anti-corrosion ability, Heat pump water heaters should not contaminate the water used during use. As an important component of piping on the hot water side, pumps must be eliminated as a source of secondary pollution. Scale problems: tap water in most parts of China are hard water, tap water residue contains Ca + +, HCO3-, FE +, Mg +, Cr plasma, after prolonged use of water pumps and piping will occur scaling phenomenon. As the shielded pump shaft and bearing lubrication is dependent on the lubrication of the transport medium, the problem of scaling can not be avoided. Especially in a long time down state, the water stays in the pump, the scale may cause shaft and bearing blocked phenomenon. Resulting in heat pump water heater started, the pump can not start causing the exhaust temperature is too high compressor protector continues to open phenomenon. Energy efficiency requirements: According to the national standard "household and similar purposes heat pump water heater" regulation, heat pump water heater in the calculation of energy efficiency, the actual power consumption of the pump must be added. In addition, the energy efficiency requirements of circulating heat pump water heaters above 3.6, higher than the 3.4 requirements of the static heat pump heat pump water heater, so the pump energy consumption is even more important.