City water line filling fresh water tank

collinsRVLife · 06-07-2014, 03:58 AM

Hi. I just bought my first travel trailer (keystone cougar 31sqb). I've rented a few times over the years, but definitely pretty new at this.

We took it out for the first time a few weekends ago. I wasn't dry camping, so I didn't need the fresh water tank. I hooked the city water connection up and all of the faucets worked. After a few hours, I noticed water leaking out of my fresh water gravity fill. I did some troubleshooting and realized that the city water was filling my fresh water tank.

I took it in for service because there had to be something wrong. All of the RVs I've ever rented, this never happened. They told me that this was operating properly and that I left my city water connection on too long and I was supposed to use my water pump for my water supply needs.

This still doesn't sound right to me. Is this really the way it is or is there some valve in the wrong position that I don't know about? I don't plan on doing much dry camping and this explanation sounds like a real pain.

Thanks for any help!

**JRTJH** · 06-07-2014, 05:34 AM

First of all, welcome to the Forum. As for your question, your dealer just ignored your problem and sent you on your way without fixing the issue.

There are two "one way valves" in the water system. The first is on the back side of your city water connection. Its purpose is to prevent water from the fresh water tank from flowing out the city water connection when you're using your water pump. The second (and the one that is not working on your RV) is on the output of the water pump. Its purpose is to prevent water from flowing through the pump head and into the fresh water tank when you're connected to city water. On some pump models it's a separate valve, on others, it's built into the water pump and the entire pump must be replaced.

There are two reasons why the one way valve would be leaking. First, it's defective and needs to be replaced. The second, and one you should try before going any further is that the one way valve is being "overpressurized" by your city water connection. Most RV plumbing is rated at 60 PSI and if connected to a water supply higher than that, could have problems. Get yourself a water pressure regulator and install it on the city water faucet. Then connect your supply hose to that regulator and to the RV. See if it solves your problem, if so, you're "good to go" if not, then the one way valve on your water pump is defective and needs to be replaced.

Your dealer didn't do you any "favors" when he sent you on your way without addressing your problem. That's probably something you'd want to remember when you go back and he gives you some "cockamamie" excuse for the next issue you have...... Trust is a hard thing to regain once it's lost, I would be cautious with the person who told you that it's normal to have a leaking valve and that you're "supposed to run off the water pump" even when hooked up to city water. That's not the way the water system works !!!!

Get that regulator (WalMart sells a cheap one for about $10) and see if it works, otherwise, it's back to the dealer......

jsmith948 · 06-07-2014, 05:41 AM

On our Cougar 5er, the water tank is gravity filled and there is a check valve in or near the pump that prevents filling the tank via the city water connection. On some of Keystone's models, it is possible to fill the water tank via the city water, but, there is a valve that must be switched. As you stated in your post, you should not need your water pump and water tank when you have city water available. Sounds like your dealer doesn't want to possibly have to replace the check valve, or, his service guy is new?

collinsRVLife · 06-07-2014, 12:04 PM

Thank you all for confirming this.

So, I have a 55psi regulator already, so it must be the check valve or water pump.

Well, I have to pick it up from getting other warranty work, so I'll have an opportunity to ask the tech directly. I get to be nice one more time, then find a new service center for sure.

audio1der · 06-09-2014, 05:59 PM

Ours did this also; easy warranty replacement on a one-way valve in the water pump.

dandjh1958 · 06-11-2014, 07:55 AM

Make sure you check the regulator. Last trip my regulator showed as 60 lbs of pressure but the water was trickling out. The very first trip in my trailer, I used a cheapo regulator and it was too much pressure and my fresh water tank filled up. I now carry three good regulators just in case one goes bad.

Happy camping!

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