Black tank fills when filling fresh tank

[Mindycpa]

My husband and I bought a new 2015 jayco RedHawk 23x2 on the Chevy chassis a year ago and have had a periodic problem (3 times) of the black tank filling with fresh water when filling the fresh water tank. We have Told the dealer (says it is impossible) and sent an email to jayco customer service (with no reply yet). Has anyone else had this problem? We are now questioning the vent system and check valve in the black tank. Any help would be greatly appreciated.

[schiguy]

I have not heard of that before, but it sounds bad to me. If your fresh water is getting into your black tank, then could the black water be getting into your fresh tank?

[Mindycpa]

We have the same concern. But can't get help from the dealer as it is periodic not consistent so it is hard to duplicate

[tnchuck100]

The first thing that comes to mind is you are hooking up your hose to the black water flush system instead of the fresh water fill.

There should be NO way for water to move from the fresh water system to the black water tank EXCEPT via the toilet flush.

[Mindycpa]

Nope, attaching to the city fill inlet. We have watched the spray into the toilet when sanitizing the black tank while hooked up to the tank sanitize fill. We will watch the toilet now when filling the fresh tank-great suggestion. Hopefully the toilet is the problem. Thanks

[Chrislorl]

If your hooked up to the city water connection then maybe it is leaking past the valve at the toilet where you flush. Are your vents on the fresh water tank clogged? If that is possible it will look for a way to release the pressure.
Ours has a tank fill on the rear, city water is separate and just for that.

[Griswald One]

Originally Posted by Mindycpa

Nope, attaching to the city fill inlet. We have watched the spray into the toilet when sanitizing the black tank while hooked up to the tank sanitize fill. We will watch the toilet now when filling the fresh tank-great suggestion. Hopefully the toilet is the problem. Thanks

I am confused as to what you would be watching when cleaning the Black tank? The Black tank flush is a device inside the tank, essentially an octopus which waves it's arms and sprays the interior surface? I can't imagine you open the toilet valve while that is going on as it would likely spray out at you???

As others have said, for obvious sanitary reasons, there is no link between your fresh water system and the black water tank. The only two access points are the toilet and the black tank flush.

I am guessing by Tank Sanitize you mean the settings on the two dials on your rig. I think that is positions 1 and 4. That is not for sanitizing your black tank. That is for sanitizing your fresh water system.

The black tank flush is achieved by connecting the hose directly to the water intake designated for that purpose. In your case I believe it is the connection below the "City Water Connection".

I would bet a significant sum that you have hooked your hose up the "Black Tank Flush" instead of the "City Water Connection"

[Mindycpa]

We will check that too, thank you. Another thing that happens that may be related is when we drain the kitchen sinks. When both sinks have water and the drains are both pulled at the same time, the sink in the bathroom gurgles and a spray of water shoots up about a foot into the air. This makes us think there is a vent problem but we don't know quite where to look. When filling the fresh tank, there is overflow coming out of the bottom of the coach which is what it is suppose to do.

[wags999]

Originally Posted by Mindycpa

We will check that too, thank you. Another thing that happens that may be related is when we drain the kitchen sinks. When both sinks have water and the drains are both pulled at the same time, the sink in the bathroom gurgles and a spray of water shoots up about a foot into the air. This makes us think there is a vent problem but we don't know quite where to look. When filling the fresh tank, there is overflow coming out of the bottom of the coach which is what it is suppose to do.

Your kitchen sink is higher than your bathroom sink. If you pulled both stoppers it is possible that the amount of water going down the drain (may be a common drain into the tank) can't handle the flow and it would back up into the bath sink.

I agree that most likely you hooked the water up to the black tank flush connection and filled the black tank. It can get very confusing.

Good Luck.

[Mustang65]

Is it possible that Jayco put the labels on the wrong fill points?

Don

[Mindycpa]

No, labels are correct. I have actually put the hose on the wrong connection and have had the black tank fill. So, I do know the difference between the the fresh and black tank fills. We are questioning whether or not there may be a valve problem that perhaps 'sticks' periodically and allows both tanks to fill. When this does happen, you can actually hear the black tank filling with water and watch the tank indicator lights show both the black and fresh water tank filling with water. I have requested a schematic diagram from Jayco on the valves so we can see if there is something there, but have not received any response at all from customer service on this issue.

[Mindycpa]

The water doesn't back up into the sink, it actually shoots a foot into the air and sprays water all over the mirror above the sink. Unless you are looking at the sink when it happens, you miss it.

[jloco]

I didn't even know you could fill the FW tank via the 'city' hookup. I thought they were all gravity fill . That must be a class 'A', class 'C' feature?

[Robbbyr]

Properly plumbed, there should not be any connection between the fresh water plumbing and the black tank flush or tank itself. The black tank flush is a dedicated connection and line to the flusher itself. And gray water should not enter the black tank. Likewise there should not be any connection between the black and gray tanks, except at the sewer drain connection. There was a time when some manufacturers would connect a gray water drain to the black tank, but today that violates the RVIA standards.

Could someone have modified the plumbing to incorporate a direct connection between the two; it is possible but certainly not advisable. I think you mentioned you bought the unit new. Could it have been mistakenly connected somehow when built, also possible, but then the dedicated flushing connection might not work.

A very interesting conundrum, I will be watching to see if you get any answers.

[mike837go]

Originally Posted by Mustang65

Is it possible that Jayco put the labels on the wrong fill points?

Don

Jayco make a mistake?!?!?

Surely, you jest!

[Jerald61]

Don't know if you've seen a basic drawing of how most RV fresh and black water systems are connected. Looking at this shows that there is not a way that fresh water should get into the black system or black into fresh water system. Hope it helps. I'd like to know what you found out is the problem.

[wags999]

I guess there is a possibility that the toilet valve is faulty and when you connect to the city water it allows the water to flow into the black tank. I would assume you could hear or see this happening, but, it should be the only point that fresh water can gain entry into the black tank. I have seen someone leave both black and gray tank drain valves open and put the cap on. Water could back from the gray tank into the black tank.

My suspect would be the toilet or a wrong connection to black tank rinse.

Good Luck tracking it down. Please keep us informed

[Jerald61]

Yep I would suspect the toilet valve leaking.

[Mindycpa]

Originally Posted by jloco

I didn't even know you could fill the FW tank via the 'city' hookup. I thought they were all gravity fill . That must be a class 'A', class 'C' feature?

Here is a picture of our valving door. We are thinking that sometimes the valve sticks open when it should be closed when adding fresh water but can't figure out how/which one. (there are several combinations to choose from). We REALLY wish it was the 'old style' fill, much simpler.

[Mindycpa]

Sorry, I can't get the picture to post. Probably has to be in PDF, only have it is jpg.