Problem filling fresh water tank

Make sure a faucet is open while you are trying to prime the pump. It may not pull water and prime, if there is nowhere for the downstream air to escape. Opening a faucet gives the air somewhere to escape.

I used to have a similar issue with the pump. Found that the suction hose was factory routed about 10 feet. I found a shorter route of about 5 feet and the problem went away.

samsontdog wrote:
...only fill the tank half way....tried to fill coffee pot and water would not pump up to faucet. Went back and filled the tank all the way up and it worked like it is supposed too.

Where is your overflow/vent on the tank? I had a similar issue in my new-to-us 5er last year. Filled the tank, drove 10 hours to destination, and during a shower ran out. I later discovered both my drain and my overflow/vent are underneath the trailer. While traveling the water splashing in the tank was able to go out the overflow and I lost most of my volume. I talked to the previous owner and he said, 'oh yeah I forgot to tell you that happens. I used to stick a bolt in the hose when we drove'.

Since then I have installed a ball valve on the overflow hose so I can close it for travel then open when I'm at my destination.

K

Maybe freeze damage to the pump? Many pumps have a small clear strainer just before the pump. I have seen these freeze and crack which causes an air leak and the pump will not prime.

could you be loosing water from a loose plug in the water heater?

It is a 40 gal tank and I put in 20 gallons, 5 gallons at a time with a 5 gal bucket after we arrived at the Camp Gd
TT was level as it was set up for camping
As I said we have camped at this camp gd before and put in half a tank and it worked as it should
Oh well we don't camp without full hookups much any more but we love camping in the High Sierras on Federal Land

How do you know you filled it half full? If you're going by the little red lights those a extremely inaccurate so maybe you didn't have as much water as you thought you had. Also, some tanks will siphon water out while in transit.

Many have the supply port well above the bottom of the tank. If you were using the gauge to determine the water level, know that they are not reliable. I moved my pickup to the drain port so that I could use all the water.

Silly idea -- could it be that your trailer was not level, so that the pickup hose was high and dry until you filled the tank? Frankly, I doubt whether that was the problem -- the pickup hose is usually near the low point of the tank, and you would have to be tilted at 45 degrees to expose the pickup.

Maybe try to replicate the problem at home, filling the tank to a quarter, then a half, and so on, trying out the pump at each level?

Anyway, let us know what you find out!! Interesting problem.

Bucky Badger wrote:
Maybe it didn't prime long enough?

Tried priming it for several hrs