To select the pump which will best suit your purposes, you need to know your pressure requirements: How much pressure do you need to generate in order to transfer a volume of fluid from point A to point B?
Knowing how your pump sounds when it's running healthy can save you a lot of money in the future. Every pump will make a “healthy” free flowing sound as a medium is passed through it unimpeded.
If you've bought a reliable pump and it has been correctly installed, you shouldn't have any issues for many years. But it's important to remember industrial and mining pumps
Have you serviced your pump recently?