When city water hooked up, it fills the water tank

[TammyMark]

We are wintertime full timers, and we have a new problem while on city water. it's started to also fill our water tank. We noticed this when we saw water overflowing onto the ground below the motor home.

[JamieGeek]

How new is your coach? Typically construction debris get lodged in the water pump keeping the check valve open.

Turn off your city water and run your pump for a few minutes. That usually is enough to clear the debris and keep the valves closed. Then you can go back to city water.

[TammyMark]

We'll try that. Thank you!

[lwmcguire]

There may be a check valve sticking or broken as well. Check the plumbing from the city water inlet to verify if there is one or not and it not it has to be the pump checks

[16ACE27]

Originally Posted by JamieGeek

How new is your coach? Typically construction debris get lodged in the water pump keeping the check valve open.

Turn off your city water and run your pump for a few minutes. That usually is enough to clear the debris and keep the valves closed. Then you can go back to city water.

Originally Posted by lwmcguire

There may be a check valve sticking or broken as well. Check the plumbing from the city water inlet to verify if there is one or not and it not it has to be the pump checks

The check valve at the city water inlet stops water from going out that connection when you run the pump. It would have nothing to do with the OP's problem.

[lwmcguire]

Well most of us know all coaches aren't plumbed the same way and some are modified to all pressure filling of the fresh water tank

So follow the fresh water line and check it out

[JamieGeek]

Originally Posted by 16ACE27

The check valve at the city water inlet stops water from going out that connection when you run the pump. It would have nothing to do with the OP's problem.

Not talking about that check valve. A water pump is, essentially, two check valves in series between the piston--at least a reciprocating pump is. The check valve in the pump. Even if the pump isn't reciprocating its going to have a check valve to keep pressure in the system when the pump isn't running.

[16ACE27]

Originally Posted by JamieGeek

Not talking about that check valve. A water pump is, essentially, two check valves in series between the piston--at least a reciprocating pump is. The check valve in the pump. Even if the pump isn't reciprocating its going to have a check valve to keep pressure in the system when the pump isn't running.

My comment was not directed to your response. Notice who I quoted? Obviously I know about the integrated check valve in the water pump.

[AlmostRetired]

If you have a Kantleak water control system, that is your culprit. I’ve had three replaced and manufacturer always says factory and dealers aren’t installing correctly. It’s never their product according to them. Methinks they are silly.

[SteveW]

The diaphragm in the water pump either stuck, has debris, or is faulty. I would try running the pump for a few minutes to see if will clear itself. I had the same problem and it started working after I cleaned plastic drill shavings out of the pump. I also installed a shut off valve in the fresh water tank fill line in case the city water bypasses through the pump again.

[Wally]

I had identical problem. Replaced 3 way valve for filling fresh water tank which corrected problem. Apparently leaking by tank shutoff position.

[Chrisutt]

Actually had this problem a few weeks ago, wound up having to replace the pump. Still under warranty, so it wasn't bad.

[suenmike]

We had the same problem with our Miramar 34.2
I replaced the Anderson valve, no luck. Finally I had the time and patience and removed the pump and diaphragm and dissected it on the back porch picnic table. This was not very hard to do. What I learned was that one of the O-rings in the pump had dislodged from its seat and was protruding out just enough to let water enter the fresh water tank.
I have no idea how this happened, but it did. When I put it all back together it functioned properly. What I did do as a follow-up, was add a ball valve to the hose between the Anderson valve and the freshwater tank so this would never happen again. Hope this helps, good luck

[rynosback]

If you have a Kantleak system it might be as simple as replacing the stem. Here is a post I made on it.
http://www.thorforums.com/forums/f29...leak-2832.html

I also installed a shut off valve in-line Incase it went bad again.

[MLP]

Two things cause this. One is a faulty Anderson valve and the other is a bad water pump check valve. First time in my now former fifth wheel was the Anderson valve. The second time it was the water pump check valve. The fist time I removed the Anderson valve center stem. One of the seals was crumpled up and out of position. After that I took it apart once a year and lubed it with plumbers grease. Worked smoothly after that. The second time I was on a trip and took the stem out of the Anderson valve and found that it was fine. So I purchased an external check valve as a quick fix and put it in line with the water pump. Fixed the problem. I do not know any other reason the fresh water tank would fill except for these two failures. Those without an Anderson valve would not under stand and those with a separate external not integrated fresh water tank fill would not as well.

[Dr.Drone]

Originally Posted by MLP

Two things cause this. One is a faulty Anderson valve and the other is a bad water pump check valve. First time in my now former fifth wheel was the Anderson valve. The second time it was the water pump check valve. The fist time I removed the Anderson valve center stem. One of the seals was crumpled up and out of position. After that I took it apart once a year and lubed it with plumbers grease. Worked smoothly after that. The second time I was on a trip and took the stem out of the Anderson valve and found that it was fine. So I purchased an external check valve as a quick fix and put it in line with the water pump. Fixed the problem. I do not know any other reason the fresh water tank would fill except for these two failures. Those without an Anderson valve would not under stand and those with a separate external not integrated fresh water tank fill would not as well.

Which side of the water pump did you install the external check valve? Input side or output side?

[WearyTraveler]

I have a Kantleak (which does!) and have the same problem as the OP.

When I purchased the RV in Nov 2019 and connected to city inlet and the switch was on “city fixtures” all appeared fine. The FW tank didn’t get filled.

I winterized (turned the switch to “winterize”). Then dewinterized for this trip to FL. The stays in parks was fine. When we got to FL and parked in BIL’s yard and connected to his water, things went awry.

“City fixtures” gave us water at the faucets AND filled the FW tank to overflow and forced water out the overflow valve at the tank’s top. So we Amazon primed a new valve. Replaced it and it worked fine for a day or so... Then the FW tank overflowed again.

I called ABCO and explained that I am an “unhappy camper.” I ended up buying a new complete panel from them. We’re waiting on it to arrive.

I like the idea / setup that the Kantleak does. But man, it’s a POS!

[WearyTraveler]

Originally Posted by MLP

Two things cause this. One is a faulty Anderson valve and the other is a bad water pump check valve. First time in my now former fifth wheel was the Anderson valve. The second time it was the water pump check valve. The fist time I removed the Anderson valve center stem. One of the seals was crumpled up and out of position. After that I took it apart once a year and lubed it with plumbers grease. Worked smoothly after that. The second time I was on a trip and took the stem out of the Anderson valve and found that it was fine. So I purchased an external check valve as a quick fix and put it in line with the water pump. Fixed the problem. I do not know any other reason the fresh water tank would fill except for these two failures. Those without an Anderson valve would not under stand and those with a separate external not integrated fresh water tank fill would not as well.

Where did you install the check valve? In doing so, did the CV stop something that would normally have allowed water to flow? Basically, did all the functions of the Kantleak still work as designed?

If the inbound Kantleak doesn’t solve my issue then I may have to use your workaround. Which check valve did you use? A picture would be greatly appreciated. I’d like to duplicate your solution.

[j37genie]

It takes a 1/2 inch ball valve. You can pick up one at Home Depot for around 8 bucks. Also pick up a couple of clamps. Determine which water line coming out of the water switch feeds the FW tank. Cut the line, and install the ball valve using the clamps. When installing, make sure the valve is positioned so you can easily operate the valve.

[j37genie]

A pic of installed valve