Water Boosting System
The water authorities are only obliged to provide a pressure of 0.7 bar and 9 litres per minute to the boundary of your property. People who experience anything more than this pressure should understand that they are very fortunate. It is necessary therefore to increase the water pressure in certain areas where either the property pipe work is extremely restrictive or the property is significantly elevated and the water main pressure cannot overcome the static head pressure. Unless in extreme circumstances (usually fire systems), you are not allowed to install an inline pressure pump that pulls directly from the main. - Instead you have to install a small break or water storage tank with a suitable air gap and overflow to avoid back washing into the authority main. From this tank you can boost the water to the required pressure and flow rate to the property.
When choosing a pump, it is not only important to choose the correct type of pump, but also the correct size of pump. These are largely dependant on the pipe size, static head and length of run.
Each pump will have its output graphed as a 'pump curve' drawn up by the manufacturer. This graph should be used in conjunction with a system curve which will show an expected duty point on the graph.
If the pump is incorrectly sized it will be pumping against closed value or off the end of curve. So whereas often a pump will actually deliver the liquid to the destination, it is not always obvious that it can also be struggling to do it! This also means that the pump can possibly be running with excessive electrical loading and at incorrect temperatures. This will effect the lifespan of a pump.
The next most significant cause of pump failure is the selection of an inappropriate pump type. There are commonly two types of pump functions; a pump to deliver a high pressure and a pump to deliver high flow rates.
Fore instance, if your house had poor water pressure, you would need a high pressure output without necessarily wanting an increase in flow. Whereas if you were trying to empty a water tank over a short distance, you would need very little pressure but a high volume output without having an excessive wait to complete the job.
Higher pressure pumps (ie approx 2 bar upwards) generally have little dirty water handling capabilities. The tolerances in these types of pumps are so high that the composition of the fluids and particles can either be very abrasive or more commonly blind the tight passages in the pump and ultimately can block it. In addition to the pump running hotter whilst it is working harder to overcome the large resistance's, it also relies on the constant flow and surrounding water (or air if free standing) to cool it. Therefore one problem can quickly provoke other problems and contribute towards the demise of a pump. Apart from additionally installed pump protection systems (excluding electrical and thermal overloads), few installations are properly protected against blockages and dry running.