I regularly have trouble filling my RV’s fresh water tank. I have a 2018 Rockwood Windjammer TT. When filling the tank, the water starts to come back out the filler tube, and when I check the panel, it’s says 1/3 to 2/3. I have tried to turn on the pump, open a faucet, rock the trailer, fill slowly (as recommended by others on FB).
The last couple times I shot compressed air bursts down the vent tube (right next to the filler tube). I almost immediately have water shooting back out the vent tube. Then I hear air coming out the vent tube. When it stops, I start filling again and am able to get several more minutes of filling time and the trailer panel will flash full or the light stays on full. I thought I’d run a stiffer tubing inside the vent tube to clear any obstruction, but I’m not sure that’s the solution. From what I see online this is a fairly common problem. Any help would be appreciated. Thank you. —Dave, 2018 Rockwood Windjammer
I wouldn’t say it is a common problem as I have not gotten a question regarding trouble filling an RV’s fresh water tank in several years, although I have come across this problem myself. One time it was a kink in the supply hose that restricted water flowing into the tank when the water source had high pressure. I tried running a fish line down the tube as well as different descaling solutions, but it continued.
Bent supply tube
What I eventually found was a slight kink that got worse as the weight of water came into the supply tube and bent it even further. I replaced the tube, which was not an easy task, and installed a spring “bend” protector to keep it from kinking again at a point in the tube where it started to bend slightly.
If your supply tube does not go straight to the tank, but rather bends upward or even goes below the tank then up, it would be best to remove the fill port and shorten the tube so it goes straight to the tank, with no bends or dips.
In another situation it was the vent tube not being large enough to allow air to escape the tank as I filled it up. Since you shot compressed air down the tube, I would assume it is not plugged but could be kinked or just not large enough to allow air to flow. However, if you get several minutes of filling after the compressed air bleeds out, it does point to a possible kink in the vent hose. Most of these hoses are just a cheap 1/4” hose that is flimsy. I would recommend replacing it with a stiffer hose.
Since your rig is a travel trailer, hopefully the water tank is accessible under the dinette seat and you can get at either the fill tube or the vent tube.
You might also enjoy this from Dave
Beware damaging your RV with high water pressure in campgrounds
“I just bought my first RV, a Keystone Springdale travel trailer. I’m concerned about the water pressure at campgrounds. I’ve heard horror stories that too much pressure can damage the water system. Are there ways I can keep that from happening? Do I need to be concerned?” —Lana
Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”
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