water pump question

[xray350]

We went camping this weekend in our Montana 2980rl (2004). Filled fresh water tank completely and after several days and alot of water usage, the water pressure dropped to almost nothing. Fresh tank level monitor said E, which I expected. We wanted to test how long we could go on one tank for boondocking later. Surprisingly though, when we emptied hot water heater it was nearly full. Also, when we opened fresh water drain, it drained out several gallons. I took precautions to ensure we were level on campsite. Anyone can help with this? It seems the pump stops providing enough pressure when water is low, but not empty? Pump was still running and air bubbles were in the line, which is why I thought tanks were empty. Also, should it pump all water out of hot water heater even if fresh is low?

Thanks,
Derek

[MarkS]

When the pump starts sucking air out of the fresh water tank, it stops pumping. Maybe a little air gets pumped, but nothing useful.

That leaves the WH and the piping downstream of the pump full.

The Pump is between the fresh tank and WH, so the pump can't pump out of the WH.

[ctpd814]

On my last trailer, the tank outlet to the pump was on the side of the tank near the bottom. The tank drain came from the bottom. The pump would start sucking air before the tank was completely empty but when you opened the the drain there was still water in the tank. I am guessing yours is the same way.

[therink]

X2 what was said above. Air bubbles will cause the pump to lose prime before the tank is empty. Most poly water tanks tend to have a low spot or two depending on how the tank supports are configured.
Water heater doesnt empty unless you pull the plug and drain it.

[GaryWT]

Common stuff so you are not pumping any crud that might be in the very bottom of the tank. The pump will pump water to the he tank but with no pressure behind it it will not empty the tank. This is a good thing as you would burn it out possible if the tank was empty.

[hankaye]

xray350, Howdy;

Now you know why there is water left when the pump stops.
The reason your monitor shows E when it's not and F before it
truly is because they need some space to mount the studs into
the walls of the tanks. The E is probably at the inch or 2 above
the bottom, the F is probably an inch or 2 below the top, the
middle one is left up to, as I refer to it, "The Stolfitz Kid" as to
how close to the middle it truly is.

hankaye

[Ken / Claudia]

Afew years ago I tested my Artic fox and found same thing happpened. I believe the others comments are right and if I tested the current trailer I would get same results. I know that when the light shows 1/3 I need more water.