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Chatter210's avatar
Chatter210
Explorer
May 31, 2016

Water Pump confusion - Can somebody clarify?

NEW RVer but fairly well read about RV water systems in class C RVs.

Just taken my 2nd trip camping to 'full hookup' park and am perplexed about something I thought was pretty easy. In an '06 Winnebago class C.

I have always hooked up to city water with good water pressure (and using a regulator) and have no issues with any faucets. I leave my water pump switched OFF naturally. NO WATER in my fresh tank at all.

Q: How come when I switch on my water pump (as an experiment) it runs continuously?
I though the pump would only run when a 'demand' caused it to start? I also thought that the city water pressure would keep the pump from running because of the back pressure?

My first trip it did this for a few tries, let it run a minute, then it stopped doing this as I thought it should. It should NOT run at all when you turn it on if you are hooked to city water correct?

Second trip it, same experiment, different park, it would run continuously. Still an empty fresh tank, no leaks anywhere in the system.

Is this a malfunction?
  • The pump will also run-on if the low point drain valves are not closed securely and any faucets are open or leaking. It's probably good for the pump to fill fresh water tank and use the pump once in a while.
  • Yup, need water in tank for pump to achieve the water pressure needed to stop it; otherwise it's just cycling through air and has no pressure to stop it.
  • Don't you have a switch to turn the water pump off? When running from city water you should flip the water pump to "off". Problem solved.
  • I think its because your tank is empty. Fill it half full and try it. Mine runs continuously when the tank is empty whether Im connected to city or not.

    It also runs with water in the tank when switched to fill.
  • Your pump only pulls from the tank. The line between the pump and the city connection is empty (there is a back flow protector that prevents the city water from back pressuring the pump, and into the tank. If you throw about a gallon of water into the tank, it should be enough to fill the pump and that line, then once filled, the pump should shut off. Not a bad way to test your pump,