Water Flow After Switching Pump Power Off

AnOldUR

@ScottG and I have been having a pump discussion in another thread, but I have a question for those not following it. There's a by-pass adjustment on the Shurflo pump that I believe will control how much water can be drawn after switching off the pump. Currently I can get almost a gallon. @ScottG gets none. What is your experience?

bergger

I thought the bypass screws were there to stop any pulsating, or hammering of the pump that may occur when you open the faucet to anything less than full pressure?  With the pump off won't you only get whatever water can be pushed out by the pressure in the lines?  Which should not be much.  I believe we get none or just a tiny bit but it's been almost 7 months since we've been able to use our water in the trailer so I can't be certain of that.  I will have to check ours when I de-winterize, it's currently 16 degrees and snowing, so it'll be another 3 weeks or so before I do that! 

AnOldUR

@bergger The manual say, "The by-pass is a spring loaded diaphragm that opens up allowing water from the discharge side back to the inlet side."

I took that to mean that it allows water pressure built up after the pump to start bleeding back to the fresh water tank once the set pressure is reached. It should be set "at least 10 psi higher than the pump shut off pressure." If set too low the pump will not shut off, but wonder if any condition could allow it to reduce water pressure after the pump is shut off.