Fresh water tank fills up on its own when hooked up to city water

[John and Cathy]

Hey folks,

Hope someone can offer me a solution. I have 2012 Carriage Cameo 5ver. Had water pump replaced last spring. Since then I have experienced and intermittent issue. For no apparent reason my fresh water tank fills up when the water pump is off but I am hooked up to City water. It has filled to overflowing twice. It doesn't do it all the time. I try to monitor it but don't always catch it in time. Any ideas on what may be causing this and how to correct it?

 

Thanks for the advice/info.

 

[chirakawa]

Hey folks,

Hope someone can offer me a solution. I have 2012 Carriage Cameo 5ver. Had water pump replaced last spring. Since then I have experienced and intermittent issue. For no apparent reason my fresh water tank fills up when the water pump is off but I am hooked up to City water. It has filled to overflowing twice. It doesn't do it all the time. I try to monitor it but don't always catch it in time. Any ideas on what may be causing this and how to correct it?

 

Thanks for the advice/info.

 

 

There's a check valve between the city water connection and the pump outlet to prevent this. I'd say it is malfunctioning and city pressure is flowing through the pump back into the tank.

[Mark and Dale Bruss]

Do you have an Anderson 4-Way valve? If so, they sometimes leak and Anderson has a repair kit.

 

The other source of filling the fresh water tank is leakage from the reverse valving in the pump.

[John and Cathy]

Don't know if or what kind of valve I have. I'll will check it out tonight when I get home.

Thanks

[pjstough]

At our fresh water city connection there is a valve that allows water to go directly into the RV, or the water can be diverted to the onboard tank. I have had this valve fail, which then fills the onboard tank, even when set in the "city fill" position.

[Big Greg]

My money is a flakey check valve in or attached to your new water pump like chirakawa has said. We

had the same intermittent problem you describe and it was the check valve in the pump. Rather than

replace the pump we added another check valve on the pumps output, problem solved. Greg

[Kirk W]

Most RV water pumps don't have a check valve but are diaphragm pumps that act as a check valve when not operating. While it isn't common, the do sometimes leak back and that could be fixed by adding a check valve to the outlet of the pump. There are also pumps that have a check valve built in and a few use a separate check valve. It might help if we knew what fresh water pump you have. If your RV has one the "tank fill" valves they also could be leaking. On our previous RV there was a tank fill valve that was separate and only supplied the tank & if it was not completely closed, the tank would fill until water came out of the vent.

[A&KHayes]

Sounds like the issue we'd had with our Anderson Kantleak water selector valve. The o-rings in the valve can get out of position if the selector is moved under pressure which allows water to flow differently than selected. If your rig has this, all you have to do is pull the selector out an repair/replace the o-rings. Lubricate it with silicone grease.

[57becky]

We had ours do the same thing last year. After thinking about the cause, I went to a local hardware store, purchased a check valve and two shark bite adapters to thread on to both ends of the check valve. I installed the check valve into the fresh tank side of the water pump. Works like a charm. The check valve is pictured in the lower left of the photo.

 

[John and Cathy]

Thanks everyone.

I don't find an external valve. City water inlet flows through a T connector to the fresh water tank. The other part of the T connector comes from the water pump which is obviously after the fresh water tank. The third part of the T connector goes to the faucets etc. It must be something internal in the pump allowing the fresh city water to flow through the pump into the tank. I will probably try installing an external valve between the T connector and the pump to prevent the fresh water from flowing through the pump.

 

Thanks again everybody for the expertise and the pictures.

[John and Cathy]

OOps sorry folks, Correction my fresh water tank fill line runs directly to the fresh water tank not through the T connector. The city water inlet runs through the T connector. What can I say, long day. Hey Kirk, I am going to be away from the forum for about a week. When I return I'll try to have the model of the pump I have and post it.

Thanks again folks.