Fresh water tank always full

[F117plt]

My fresh water tank remains full all the time, even when I have not filled it. Obviously the tank fill valve is allowing water through it even when the valve is turned to off. Anyone else ever had this problem? Getting to the valve is going to be a bit of a job, but I guess it will have to be replaced. Anyone think of another reason this could be happening. Thanks. BTW, Itasca Ellipse 42QD.

[Jim_HiTek]

It's difficult to tell from your description what's going on. But assuming that when you hook up to shore water, the holding tank slowly fills, then I'd think that the check valve is stuck partially open...if it were stuck full open, then you'd have water pouring out of the fill spout. There are no float valves in any RV tank I've hear about or seen. If it's as inaccessible as the fill valve, then put a new one somewhere where you can get to it.

This often happens when small plastic shavings from manufacturing make their way into the supply lines.

[topdownman]

If you can figure out how to make that happen with the fuel tank, let me know

[F117plt]

Originally Posted by Jim_HiTek

It's difficult to tell from your description what's going on. But assuming that when you hook up to shore water, the holding tank slowly fills, then I'd think that the check valve is stuck partially open...if it were stuck full open, then you'd have water pouring out of the fill spout. There are no float valves in any RV tank I've hear about or seen. If it's as inaccessible as the fill valve, then put a new one somewhere where you can get to it.

This often happens when small plastic shavings from manufacturing make their way into the supply lines.

Thanks , Jim. When you say "check valve" do you mean the valve that selects between the city water or tank fill? Your idea about putting a shutoff where I can get to it is a good one. Thanks.
Jerry

[Possum]

My buddy had an older Winnebago where the water fill and the campground potable water hookup are one and the same. He fills his storage tank whenever he hooks up to a water source.

Not sure I like this as I always carry water of a known quality in my fresh water tanks and when I am at campsites with poor or bad tasting water I don't bother hooking up to fill up the fresh water. I would rather be able to sellect when I want to fill up.

[Jim_HiTek]

Originally Posted by GBFleming

Thanks , Jim. When you say "check valve" do you mean the valve that selects between the city water or tank fill? Your idea about putting a shutoff where I can get to it is a good one. Thanks.
Jerry

I mean a device that permits water to flow in only one direction. Not a shut off valve exactly, but a small device about twice the diameter of the pipe, something like this:



Not all RVs have them, many use use a set of valves set up in a 'Shore water' or 'Tank water' system.

Others have a check valve in the plumbing to the water heater. Often in a difficult to access spot behind the tank.

Your symptoms remind me of one of those check valves behind or near the water tank having some particle of plastic blocking it open a bit. When the shore water pressure is greater then the systems pressure, it forces water back into the holding tank passed the slightly open check valve.

[Skip426]

It is also possible that the 12v water pump has an internal check valve leaking. That can be tested by removing the pump inlet when hooked to city water. Use caution, fresh tank may be above pump so you have to be ready for flow from the inlet hose.

[palehorse89]

Is there a check valve on this side of the water fill? I just have a 1/4 turn valve to open and it directs the city water into the tank, when full close the valve, I do have a check valve on the incoming water filter though.
Is the tank overfill have water running out of it after being hooked up to city water and the tank becomes full and does not stop? Is this what you are saying?

[F117plt]

Originally Posted by palehorse89

Is there a check valve on this side of the water fill? I just have a 1/4 turn valve to open and it directs the city water into the tank, when full close the valve, I do have a check valve on the incoming water filter though.
Is the tank overfill have water running out of it after being hooked up to city water and the tank becomes full and does not stop? Is this what you are saying?

Thanks to all. I don't think my RV has any check valves, at least none I can find. I do have the City Water/Tank Water valve. Yes, the tank fills and overflows when I have that valve in the City Water position, so the valve must be leaking. Am going to try to find a valve tomorrow. I am in Tucson and will try Lazy Days.

[DancinCampers]

If this is the white valve that Winny uses alot, you can replace just the inside parts. More than likely the rubber seal is bad, or one of the fingers that hold the rubber seal has broken off. (I haven't found a source for just the inside parts, but have replaced
several on my previous coach. The insides from a straight valve should also work if you can't find the city water/fill one)

If indeed this valve is leaking, the pump should be cycling if you turn off the city water spigot.

[CampDaven]

When my rig was new the FW tank was overflowing one morning. It was only 1/4 full when we arrived. I opened and closed the FW fill valve in the wet bay several times. Fixed. Musta been some debris in the valve.

[rream]

This must be contagious - please post the fix as I will need it too.

[CampDaven]

Originally Posted by rream

This must be contagious - please post the fix as I will need it too.

All I did was open/close the FW fill valve several times.

[rream]

Originally Posted by CampDaven

All I did was open/close the FW fill valve several times.

Eureka I did the same and mine is fixed also

[F117plt]

Originally Posted by rream

This must be contagious - please post the fix as I will need it too.

Ha, when I started this thread I thought I was the only one!

[swyates]

Your coach is obviously a lot newer than our 05 Adventurer and the plumbing could have been updated quite a bit, but we had a similar problem last winter. The fresh water tank kept filling and overflowing. The problem turned out that the internal valves in the Shurflo water pump were leaking and allowing water to back flow through it into the tank. Replacing the valves cured the problem. Alternatively, I could have installed a check valve in the water line going to the pump, but I figured if the valves in the Shurflo were leaking, I'd eventually have to fix it and another check valve would add a little more resistance to water flow.

[F117plt]

Originally Posted by swyates

Your coach is obviously a lot newer than our 05 Adventurer and the plumbing could have been updated quite a bit, but we had a similar problem last winter. The fresh water tank kept filling and overflowing. The problem turned out that the internal valves in the Shurflo water pump were leaking and allowing water to back flow through it into the tank. Replacing the valves cured the problem. Alternatively, I could have installed a check valve in the water line going to the pump, but I figured if the valves in the Shurflo were leaking, I'd eventually have to fix it and another check valve would add a little more resistance to water flow.

Today I decided to exercise the tank fill valve to see if I could dislodge any debris that might be in the valve. When I turned the valve to Tank Fill the water pump came on. The tank was completely empty because I had drained it. The pump ran as long as the valve was in Tank Fill. As soon as the valve was closed, the pump turned off. This seemed strange to me as I don't remember the pump ever running when I was filling the FW tank. Any ideas what is going on here? Thanks.

[swyates]

The way my system is plumbed, the pump sits between the high pressure line and the tank. The city water in is also on the high pressure line. The tank fill valve sits between the high pressure line and the tank fill line. If you turn on the tank fill valve with no city water pressure, the pressure drops in the high pressure line and the pump will run. Thus, it will just cycle water from the tank through the pump, high pressure line and back into the tank. I test this a lot because I sometimes fill the fresh water tank when leaving a hookup site (because we dry camp a lot) and forget to turn the valve back to city. So when we turn on the pump inside, it starts cycling water from the tank back to the tank, making me go back outside and turn the valve. Just thinking about it, if you tank fill valve was indeed leaking, the pump would cycle as the pressure drops in the high pressure line. My bet is still on the water pump allowing water to back flow. Oh, and there's no completely empty on the fresh water tank. My dump valve isn't even on the bottom of the tank, its on the side at the bottom.

[F117plt]

Originally Posted by swyates

The way my system is plumbed, the pump sits between the high pressure line and the tank. The city water in is also on the high pressure line. The tank fill valve sits between the high pressure line and the tank fill line. If you turn on the tank fill valve with no city water pressure, the pressure drops in the high pressure line and the pump will run. Thus, it will just cycle water from the tank through the pump, high pressure line and back into the tank. I test this a lot because I sometimes fill the fresh water tank when leaving a hookup site (because we dry camp a lot) and forget to turn the valve back to city. So when we turn on the pump inside, it starts cycling water from the tank back to the tank, making me go back outside and turn the valve. Just thinking about it, if you tank fill valve was indeed leaking, the pump would cycle as the pressure drops in the high pressure line. My bet is still on the water pump allowing water to back flow. Oh, and there's no completely empty on the fresh water tank. My dump valve isn't even on the bottom of the tank, its on the side at the bottom.

Thanks, makes sense. I'll think I'll call Winnebago tomorrow and talk to one of their techs.