Still a problem with onboard water system, pump doesn't pump

[tooth ferry]

OK what am I missing? Drained tank, added 53 gal.water to tank through convenience center line so that line is open. Disconnected lines to pump and put intake line in gallon jug outlet line open and it pumped it dry in 5-10 seconds so pump works. Pump runs constantly when switch is on, will not cut off. Cannot get pump to pull from tank, no way to prime pump that I can see. Is the fill line for the tank also the input line for the pump? Can't find any screen or check valve on the pump input. Could the pump be strong enough to pull from the jug but not from the tank? Suggestions?

[K0LCB]

Pumps are usually self priming

[scattershot]

Is your switch in the convenience center set to normal flow, or fill? Set it to normal flow and it should take care of the problem.

[dieselguy]

Watch this video and take note of all valve positions ... especially the last valve shown at about the 13 second mark. (tank fill power fresh) Point it to normal flow as scattershot explained.

https://www.youtube.com/watch?v=qVSnLoTD3is

[Overlord]

Originally Posted by scattershot

Is your switch in the convenience center set to normal flow, or fill? Set it to normal flow and it should take care of the problem.

Ditto.

If the valve is set to fill, you are pumping water from the fresh water tank, and putting it right back into the fresh water tank. There is no pressure buildup, so the pressure switch does not turn off the pump.

Alternately, if your valve is set to normal, and your hot water tank happens to be empty, it takes quite a while to pump 12 gallons of water to fill the tank, and in the mean time there is also not enough pressure in the system to shut off the pump until the HW tank is full, so the pump runs and runs until the HW tank fills and pressure builds enough to trigger the pump shut-off.

....or, the pump diaphragm or anti-back-flow valve in the pump is shot(maybe it froze over the winter), and can't build enough pressure because of back-flow. I've had that happen to me once on an old TT.

[SThalhauser]

Not sure Why I am not seeing a new thread button somewhere but I am having pretty much the same problem on my 2010 Keystone Montana, 10th Anniversary Edition. Pump runs and will not shut off. When hooked to city water everything runs as usual. Turn pump on and it is not pulling from fresh water tank. I also can not fill fresh water tank when I am hooked up to city water. I think it is the valve switch. I have no where to go to look and order what I am needing to replace it. Any ideas?

[dieselguy]

As to the new thread button .. go to a forum like Maintenance or Montana Problems. You'll see the Montana Owners Club logo at top left. About 3" below that logo is a grey box that says new thread.
To get to the back of the convenience center ... remove the big plastic panel. It's screwed to the storage compartment floor and rear wall. You'll find a real plumbers nightmare like we all have.

[DQDick]

If air is getting in the lines between the tank and the pump you will never get it to pull from the tank. start at the pump and look for loose connections back toward the tank.

[rohrmann]

Assuming all the valves are in the correct position, it is very likely that a fitting at the convenience center end or the tank end of the water hose that connects to the fresh tank is loose and sucking air instead of water. Hopefully the hose does not have a hole in it, but I suppose that could also be a possibility. In the photo, the white hose that is shown angling down from the center of the photo is the hose that connects to the water tank. I would suggest accessing the back of the convenience center and tighten all the connectors. I had a leak very early after we purchased the rig, and I found several connectors loose, almost to the point that they were hand tightened, barely. Also make very sure the water pump connectors are tight also. I'm not sure what the tank end connector looks like, but that would be the next place to look for a loose connector.

[prndl]

If the OP used the fill valve in the convenience center to fill the tank then the white hose going to the tank is good as it is the same hose for fill and pump.