Why will the well pressure not go above 40 PSI even when I hold the pressure switch closed

pressurepump

My well is probably 200' deep and is about 50' from the house. I have no idea what the pump HP is.

I have tried different pressure switches and adjusted them up / down but I can never get more than 42 psi, so I have the switch set at 20 / 40. If I hold the pressure switch closed for as long as 15 minutes it still will not pump beyond 42 psi. I would really like to have 30/50 psi. I now have the bladder tank set to 18 psi for 20/40 pressure setting. In order to get 30/50 do I need a larger well pump?

(If I install a 30/50 switch the current pump never shuts off.)

Best Answer

You need a pump that will provide more pressure. That may or may not be "larger" in terms of HP - my recollection was that the most common 1/2 HP submersible pumps when I was shopping were actually set up for higher pressure/deeper wells than the 3/4 HP pump I got, but the key is that the HP alone does NOT tell you what the pump can or will do - different impeller/staging setup can do more volume at lower pressure or more pressure at lower volume from the same HP input. This is seen by comparing "pump curves" which is what truly matters when choosing the right pump.

You can make some slight inference as to pump HP from the size of the breaker (or fuse) on the pump circuit, but given the starting surge it's not entirely definitive.

My particular 3/4 HP pump works just fine (set at 40/60) from 300 feet down more than 100 feet from the house, and will draw the well from 100 feet down all the way to the pump location (my well drillers appear to have fibbed quite a bit about the GPM my well produces, since it was chosen with their numbers and the well should not draw down to pump level if their numbers were correct.)

Another possibility is that your pump impeller may have worn to the point that it no longer works as designed, and it's possible that a pump of the same power and impeller setup that was new should work fine.

When you get a new pump, be sure to stick the provided labels (usually - or just write the information with a permanent marker) on the pump control box or breaker panel or on the wall near the pressure tank so that you or the next person will actually know what pump is down the well.