Originally Posted by Heymirth
Will the water pump run constantly when the water is gone?
Yes, if the pump switch is on. The pump senses output pressure in the plumbing. Once plumbing pressure beyond the pump falls below 25 PSI (typical) the pump turns on until it senses 45 PSI (again typical).
If a faucet is open or there is a leak, the pump may never get to or sense 45 PSI, and continue to run. Similarly, if there is a leak on the suction side or no water in the tank, the pump cannot achieve 45 PSI and continues to run.
There should be a manual switch to turn off the pump, as you don't want the pump on when the camper is connected to city water (or the water tank is empty). My switch is located on the pump enclosure itself at the bottom of my under-sink cabinet. My water filter is located on an upper shelf in the same cabinet.
The Shur-flo pump can run dry for a short period time with no damage, but a short period is not hours. The water lubricates and cools the diaphragm in the pump, which in turn keeps the pump motor from being over-loaded and burning out. My earlier post described my faux pas in running the pump dry and burning out the motor because I forgot to turn the pump off when I drained the water tank.
just my experiences with 12V water pumps in boats and RVs
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time