Fresh Tank Filling on City Water

[avarusbrightfyr]

Hello all,

I'm new to this forum and wanted to start by saying hello and I'm glad to be here!

I've been living in my travel trailer for nearly a year now in a trailer/RV park and haven't really been able to use it for the "recreational" part because I don't have a truck yet. Because of that, I've been on city water exclusively since I've had the trailer. A few days ago, I wanted to make sure everything on the boondocking side of things still worked, so I switched over to the RV side on the water selector and filled the tank and ran water through the pump to test things out. Everything seemed to work fine, so I emptied the tank and switch back over to city water.

However, now my fresh tank is continuing to be slowly filled while city water is selected. The rate of fill is much higher when RV is selected and much lower when on city water, so my assumption is that the selector valve is not sealing properly, but I'd like to get some input from more experienced RVers to make sure I'm not oversimplifying. I've read some things about faulty backflow preventers on the pump causing the fresh tank to fill, so I don't want to discount that just because it hasn't been used much at all.

Any input would be much appreciated!

[Dirtclods]

bucky wrote:
I always fill the fresh tank upon arrival. It only took once to learn that lesson when the park shut the water off to fix a leak or whatever. The older the park the higher the chances.

2nd that Theirs a place our club goes Dirtbike riding and getting water is iffy...? So I always fill before I go anywhere.

[avarusbrightfyr]

rjsurfer wrote:
Yes, the backflow valve is in the pump, found that on some YouTube videos.

I looked at a post that mentioned running lots of water using the pump and sure enough after 10 minutes of continuous flow from multiple faucets the valve must have reseated and the water stopped entering the fresh water tank.

Ron W.

Good to know. I'll try to remember that for next time. Thanks for the info!

[rjsurfer]

Yes, the backflow valve is in the pump, found that on some YouTube videos.

I looked at a post that mentioned running lots of water using the pump and sure enough after 10 minutes of continuous flow from multiple faucets the valve must have reseated and the water stopped entering the fresh water tank.

Ron W.

[Dusty_R]

I believe you will find that the check valve is built into the pump.

[rjsurfer]

Timely post, my wife just noticed our fresh tank is full, it had been at one quarter. We also have water coming out of the fresh water fill.

I don't have a select valve for moving water into the fresh tank so the problem has to be a check valve in the pump?

I'm assuming it's at the output side of the pump.

Thanks

Ron W.

[avarusbrightfyr]

Ok, so this should be the final update. I got the new pump installed and the fresh tank does not appear to be filling after sitting overnight. Pump works and runs fixtures, city water works and runs fixtures. Looks like the issue is solved for now. In the end, it looks like the pump was the original culprit.

However, I'm not comfortable yet because one of the flair-it fittings started leaking. I don't know if it was a bad connection or if it's a failing in the design or what. I replaced the leaking one with a crimp fitting and it seems to be fine now. Just a shame that it started while I was at work and there's some water damage. I'll be keeping an eye on it for the next couple of weeks.

Thanks to everyone for the help!

[avarusbrightfyr]

opnspaces wrote:
I agree on that. It's way better that you found this now than two hours away out at a remote campsite.

If you are retaining the PEX (hard plastic lines) be careful with the worm drive hose clamps. They are easy to strip when tightening enough to compress the PEX. Home Depot will have the crimp rings and crimpers for the PEX lines in the plumbing section if you want to go that route. Also if you are using flexible lines make sure they are rated to handle the city water pressure. Up in my neighborhood I've seen 120 lbs pressure coming off the street. So I always use a pressure regulator when I hook up to city water.

I am retaining all the PEX connections and so far nothing appears to be leaking at all. Ideally I won't have to deal with this again for a very long time, but I'll look out for stripping things next time. The entire trailer is using braided PEX, so I think it's beefier than the thinner stuff.

I did a lot of research before buying my trailer and I do have a pressure regulator that is set to around 55 PSI, which is what my pump maxes out at as well. I'm currently only getting 40 from the city, though. San Diego isn't great for water pressure.

[avarusbrightfyr]

Another update: I got all my plumbing hooked up the way I want it and now everything works as it originally did, but now everything is screw on and easily removable if needed. It turns out the the flair-it fittings aren't sized for braided 1/2 PEX and it wouldn't fit, and that was giving me a lot of grief until a friend suggested I soak the end in really hot water to make it more flexible. That did the trick and it took like ten minutes to get everything finally hooked up again.

I did do some troubleshooting before hooking up the tank fill line, however. I ran water with the valve set to city and there was no leakage from the tank fill side of the valve even when under city pressure. This leads me to believe that the suggestion that the water pump leaking back into the tank was the correct one. I already have a replacement pump on order and it arrives next week, so we'll see if this solves the unwanted tank filling issue and my trailer is back to 100%.

[opnspaces]

I agree on that. It's way better that you found this now than two hours away out at a remote campsite.

If you are retaining the PEX (hard plastic lines) be careful with the worm drive hose clamps. They are easy to strip when tightening enough to compress the PEX. Home Depot will have the crimp rings and crimpers for the PEX lines in the plumbing section if you want to go that route. Also if you are using flexible lines make sure they are rated to handle the city water pressure. Up in my neighborhood I've seen 120 lbs pressure coming off the street. So I always use a pressure regulator when I hook up to city water.

[avarusbrightfyr]

I'm still working on getting things replaced, but I think I might start using the RV side primarily and just using city water to fill the tank. I still have to do weekly emptying of my black tank anyway, so it wouldn't be that much of a change. It will also keep the pump from sitting for long periods without being used, and I've noticed that in general mechanical parts don't like to just sit unused.

As of right now, I've bypassed my selector valve and have the water inlet connected straight to the hose that goes to the plumbing fixtures. I'm slowly collecting parts to put everything back together mostly the way it was, except that I'm going to use screw on connectors for the selector valve connections instead of clamps or crimps. That way I can just unscrew everything if I need to take the valve out in the future.

It also turns out that my water pump is bad, so I have a replacement coming in for that as well. It really sucks because it's barely been used at all...like a few times for demo before purchase, and this one time when I was testing everything out. I'm taking this opportunity to install a dc connector plug so that the only wiring I have to do for future replacements is on the pump side and it will just plug right in.

While no one is every happy to have to fix things, part of me is glad this happened now so I can figure out how all this works while I have easy access to parts and city connections.

[Bill_Satellite]

wolfe10 wrote:
And we do the opposite. Use only tank water-- refilling and dumping gray and black when out of potable water.

This way tank water is always fresh. And, this gives us the option of not filling with CG water if it is poor quality.

Yes, sanitize tank at the beginning of each trip/if water over 2 weeks old in summer or 3 weeks old in winter.

I do the same. I always supply the coach from the fresh water tank using the water pumps. I fill the tank when it's empty and dump both holding tanks at the same time. I keep both of those closed until it's time to dump to ensure enough water volume for a good clean dump. The fresh water tank is always clean and safe to drink due to the fresh supply of chlorine in the city water supply.

[wolfe10]

And we do the opposite. Use only tank water-- refilling and dumping gray and black when out of potable water.

This way tank water is always fresh. And, this gives us the option of not filling with CG water if it is poor quality.

Yes, sanitize tank at the beginning of each trip/if water over 2 weeks old in summer or 3 weeks old in winter.

[GenoB]

Just a comment regarding fresh water tanks :

I've been RVing since the early 90's with several different RV's types. In general here is how I use the internal water tanks when traveling (not when parked on city water)

a) I never use the fresh water tank for cooking or drinking or brushing teeth
b) I DO use the fresh water tank for washing dishes, showers, general wash basin uses, toilet, etc
c) I keep the tank about 1/4 or less filled when stationary in RV park, more if needed when traveling.
d) I put about a cap full of bleach when adding water to the tank to keep water from going rancid
e) I do all my cooking and drinking with bottled water

Just me personally, has worked well for me over the years. I don't like leaving a tank dry / empty, things dry up and crack, etc. Never had any problems with the tanks using these methods...

[bucky]

Lwiddis wrote:
Bucky, and if upon arrival no water is available? I never leave home or a campground without a full fresh water tank if available. If a TV and/or TT can’t handle the weight, someone bought the wrong TV and/or TT. Lots of beautiful DRY campgrounds in the West.

Good point. I usually only travel with enough for potty stops if needed.