MaxBlack
Member
Maybe you guys have ideas for me: My 3/4HP shallow well pump, for 10-15 seconds on startup, makes a somewhat harsh sound from the impeller that then "smooths out" to be very quiet, as its pumping-up from 40 to 60 psi. This pump's 1 1/4" input is tied not to a well, but to the bottom bulkhead fitting of a storage tank which always has 500+ gallons of water in it (about 8 feet of pipe interconnecting the two, at the same low ground level).
Wondering about the noise on startup--my assumption has always been (this pump has worked fine for a couple yrs now) that somehow there are air bubbles in the pump that the impeller "spins out" then things quiet down. But where would/could air bubbles possibly come from--I'm certain there are no leaks in the intake pipe, and there is always a ton or more of water on top of the intake pipe (it never ever "sucks air" from the tank).
The pump has an integral check valve and serves a large pressure tank w/bladder (below it underground), a couple of Big Blue filters (above it), and eventually a water softener and a couple of pipes to our house & garage.
As I type this the only thing I can think of is possibly air bubbles in the pressure tank below that the pump "trades back & forth" time & again? Gosh, even that theory seems unlikely--any air bubbles should rise UP thru the pipes into the filters and out the system eventually...
Like I said the pump has worked fine, the noise is not actually a problem--just wondering what could be causing this, and assuming if it's cavitation that the impeller life will be shortened thru this?
Wondering about the noise on startup--my assumption has always been (this pump has worked fine for a couple yrs now) that somehow there are air bubbles in the pump that the impeller "spins out" then things quiet down. But where would/could air bubbles possibly come from--I'm certain there are no leaks in the intake pipe, and there is always a ton or more of water on top of the intake pipe (it never ever "sucks air" from the tank).
The pump has an integral check valve and serves a large pressure tank w/bladder (below it underground), a couple of Big Blue filters (above it), and eventually a water softener and a couple of pipes to our house & garage.
As I type this the only thing I can think of is possibly air bubbles in the pressure tank below that the pump "trades back & forth" time & again? Gosh, even that theory seems unlikely--any air bubbles should rise UP thru the pipes into the filters and out the system eventually...
Like I said the pump has worked fine, the noise is not actually a problem--just wondering what could be causing this, and assuming if it's cavitation that the impeller life will be shortened thru this?