Interior Water Tank Fill Tube Nozzle

In our last article and in other articles in which I have written about sanitizing our fresh water tanks and de-winterizing, I have spoken of a continuing problem that we have had each year when sanitizing the tanks. When we get to the point that we need to flush the bleach and water mixture out of the rear, interior, fresh water tank the water backs up and pours out of the fill hole in the door frame when just a gallon or less of water has gone down into the tank. At that point nothing that we have tried to get the water to fill that tank has worked consistently. What seems to work one year has not worked the next. We have tried all ways that we can think of to get this tank to fill. The odd thing is that this only happens on the first fill after the tank has has water/bleach from sanitizing. My thought has always been that the bleach causes a gas bubble to form that is keeping the water from coming down the tube. Last year I started researching what RVers so when they can't fill a fresh tank looking for descriptions of the same behavior - back up well before the tank is filled. What I came up with were a number of recommendations to fill the tank from the bottom of the tank to the top - and not from the gravity fill tube. So how would could I do this? My first thought was to try AGAIN to fill that back tank with the city water connection - BUT that did not work.  I came up with the following "tool" - and it has worked now two years in a row.

I have been trying to come up with a name for this "tool". A long time ago a computer software engineer was working on a software tool that would enable the scanning of documents. He wanted
a really good name to go with this tool that he put a great deal of work in. Other software tools had interesting names and he wanted one too. In the end what he came up with was TWAIN". If you have a scanner you will know about TWAIN. What does TWAIN mean - ready - "Tool Without An Interesting Name!  I played around with combinations of letters and really did not come up with anything that worked for my special "Interior Water Tank Fill Tube". I have been thinking of calling it the "Bottoms Up Tool" and that may be what I decide on. For now we will just refer to it as the Interior Water Tank Fill Tube. It works - and you can make one too and I will tell you how.

This was assembled with parts from Home Depot in the plumbing and garden departments. Al of the parts are potable water plumbing safe brass with the exception of the tube and the shut off valve at the end. What you need is a brass nipple fitting for a 3/16" inner diameter tube that has the opposite end a male screw end able to connect to the next brass fitting and the size may vary by what you can find for the next piece. 

The next part is has a garden hose female screw end on one end and the other end a female screw on end sized to match the male screw end of the last part. This is basically it. I wish I could tell you the specific part numbers. I had them for this article and they were lost. But it is not hard to match up the correct parts if you do some looking in the plumbing department. You may want to ask for help. You may get strange looks when you tell them what  you are putting this together for. You may find it necessary to put a fitting between the two parts to reduce one to fit the other. For what was available in the store, I had to do that.  One more thing to be aware of is that the part that will connect to the water hose from your spigot must be specifically sized for garden hose. I learned in this venture that garden hose is a different thread from the same size part for pipe plumbing.

Now, this does not work with the tube that you are making this to use to fill your tank. You need tubing that is 5/16 outer diameter and 3/16" inner diameter. The 3/16" to match the brass nipple that you are using.

Next you want to put a shut off valve on this so that you can turn the water off right there when you are finished filling. This is found in the garden department and is just a standard plastic garden hose shut off valve. 

Assemble the brass parts tightly together. I found that even with pipe tape on the threads there were leaks so I got some plumbers tape - also found in Home Depot's plumbing department and wrapped the joints from top to bottom. This is the black wrapping that you see in all of the photos. This tape is pulled around and holds on its own - and it has not come off in two years.

Push about ten feet of tubing onto the nipple and then screw on the hose shut off valve on the other end. You are not going to put ten feet of tubing into the fill hole on the tank but you want a good amount outside with you. Just in case that tubing comes flying off the end, you want plenty outside so that there is no way that it can wind up inside the tank!

After putting it all together run some water thought it to clean out the fittings and you are ready to use it.

So here is how to use it. Attach your fresh water hose to the end. Turn on the water so that it runs slowly. Don't put the water on full force. Use less than half force or less. Turn turn on the valve on the "tool" and make sure the water is flowing, everything is holding together, and the shut off the valve. Open your rear tank door fill and push the tube down the fill hole until you are sure it has to be not only inside the tank but at the bottom of the tank. Hold the rest of the tube outside and turn  on the valve. You will see the water coming out of the nozzle when it starts.

NOW - here is something that happened and it may happen to you. As the water started going in using this, suddenly it came back up and out the fill hole - similar to before but not as much. It will spurt out once and may spurt out again the same way  BUT then it will stop and the water will continue and now fill the tank so keep going if you see that one or two spurts. Perhaps it is that bubble clinging to its last moments before it is gone. If someone is inside looking at the tank sensor they will see the progress of the tank filling. It takes a while - even though this is the smaller tank - as the water is running slower and is coming out from the much narrower tube rather than the regular hose. Once filled - done!

I keep mine in the Roadtrek. This fill problem actually happened to us once when filling in hot Virginia afternoon heat. This would fix that too. Now, if you don't have a Roadtrek 190 or a 210 you may want one of these anyway - as RVers without Roadtreks and without two fresh tanks have had this same problem too.