What causes bubbles in pool return?
If you are seeing a significant number of bubbles coming out of your return lines into the pool, you probably have an air leak in your filtration system. Possible sources of this problem are low pool water levels, leaks around the strainer lid, leaks in the unions or leaks in the pump seals.
What happens if air is present in suction side of centrifugal pump?
The presence of an air pocket in the suction line is another example of a cause for pump troubles, which should never happen. Any high point in the suction line can become filled with air and interfere with proper operation of the pump. If the liquid supply is below the pump the suction line should run up to the pump.
What is a suction line leak?
A suction side air leak is most commonly indicated by air under the pump lid. It can not be located after the pump, in this case you will be leaking water out not sucking air in. In rare cases a suction leak can be the cause of an underground suction pipe that has been punctured, or cracked.
What is the relationship of NPSH and cavitation?
It is the difference between the NPSH available (NPSHa) at the pump’s inlet and the NPSH required (NPSHr) by the pump to operate without cavitation. Cavitation is the formation of bubbles at the pump inlet, followed by their sudden collapse, which can cause permanent damage.
Why does oil hold up in a suction line?
The suction line of a refrigeration system, especially for large commercial or building systems, can be a major location of oil holdup. The low temperature and high quality inside of a suction line means the small amount of liquid will be very oil rich and have a high viscosity. A high velocity of refrigerant vapor is required to pull the oil
What causes the suction line to freeze up?
This cause the temperature of the suction line to drop, and just like in the evaporator, cause the condensation to freeze. Eventually the freezing works its way all the way back to the compressor, which is where the trouble can really start.
How is refrigerant vapor used in suction lines?
A high velocity of refrigerant vapor is required to pull the oil through long suction lines, especially in vertical, upwards flow conditions. The demand for energy efficient building systems has pushed many innovations, such as variable speed compressors, to reduce power usage during low load conditions.
