Fresh water and rear black tanks filling unexpectedly

Icantdrive55 · 07-28-2020, 07:52 AM

As if I haven't had enough issues, with only 35 miles on the trailer since purchased new, I've had another issue I can't figure out creep up.

I have two grey tanks, 2 black, and a fresh water tank. In the last 2 weeks I've noticed my rear blank tank that does not get used at all, has been filling up, as well as my fresh water tank which has been found overflowing the last few days. There is a power flush system, but it has a separate hose connection, which is only connected when I actually intent to flush it.

The diagram for the water panel says to turn the water heater bypass to ON for a tank flush, even though I assumed fresh water and flush are on 2 separate systems, so I'm wondering if there is another valve that's failed and the water pump is pushing water into the black tanks too.

RV is a 2019 Fuzion 429 toy hauler, and I have no idea where to start looking for a faulty valve. Thoughts?

travelin texans · 07-28-2020, 08:15 AM

Unless some one at the factory totally screwed up your water heater bypass & black tank flush should not be connected in any way. There should not be any fresh water & black water connections anywhere other than the black tank flush line that should be a separate connection.
The fresh water is likey bypassing through the pump due some debris in the check valve, turn off city water & pump from the fresh tank for a while might clear that problem.
As for the 2nd black tank that's not being used, is the toilet running over or are you looking at the gauges/sensors? If looking at the sensors that's telling you it might have something in the tank as to how much is anybody's guess. Press the foot pedal, if you see liquid it's full, if not then there's no telling how much if any as those sensors are well known to be totally useless.

Icantdrive55 · 07-28-2020, 08:17 AM

Quote:

Originally Posted by travelin texans

Unless some one at the factory totally screwed up your water heater bypass & black tank flush should not be connected in any way. There should not be any fresh water & black water connections anywhere other than the black tank flush line that should be a separate connection.
The fresh water is likey bypassing through the pump due some debris in the check valve, turn off city water & pump from the fresh tank for a while might clear that problem.
As for the 2nd black tank that's not being used, is the toilet running over or are you looking at the gauges/sensors? If looking at the sensors that's telling you it might have something in the tank as to how much is anybody's guess. Press the foot pedal, if you see liquid it's full, if not then there's no telling how much if any as those sensors are well known to be totally useless.

For the blank tank, my sensors are showing water in the tank, and I can pull the valve and completely drain it, even though it's not been used. A few days later, water shows up in the tank again, and I drain again, rinse, repeat. I don't see any roof damage or damage to the vent either.

I wouldn't think the systems are connected, but the water heater bypass makes me wonder if the design is just stupidly flawed, and factory screw ups are not foreign to me, I'm out of warranty as of last week, and I've only had this off the dealership lot since May....

**flybouy** · 07-28-2020, 08:20 AM

As for the fresh water tank there are 2 possibilities that come to mind. You could have a valve in the wrong position or the check valve in the water pump has derbies holding it open. Can you post a picture of the city water hose connected with the valve handles in the pic?

As to the black tank, how are you determining that it's filing? If you are depending on the "tank level indicators" they are notorious for false/inaccurate readings. On some units the sink or shower may drain into the blank tank as well.

Icantdrive55 · 07-28-2020, 08:26 AM

Quote:

Originally Posted by flybouy

As for the fresh water tank there are 2 possibilities that come to mind. You could have a valve in the wrong position or the check valve in the water pump has derbies holding it open. Can you post a picture of the city water hose connected with the valve handles in the pic?

As to the black tank, how are you determining that it's filing? If you are depending on the "tank level indicators" they are notorious for false/inaccurate readings. On some units the sink or shower may drain into the blank tank as well.

I posted above, but the sensors show the tank filling, and I can go drain it repeatedly, there is water getting in and I have no idea where it's getting into the black tank from.

**JRTJH** · 07-28-2020, 09:06 AM

On ALL "two bath" trailers, there are two black tanks, one for each toilet. Toilets MUST have a direct dump into the black tank as there is not enough room to build in a "drainage slope for solid waste in any travel trailer floorplan. There are NOT gray tanks for each bath. On about half of the Keystone "two bath trailers" the second bath sink dumps into the black tank as does some "outside kitchen sink drains". So, even though you're not "flushing the second bath toilet" waste water from "sources other than the toilet" are sharing that tank...

Looking at your floorplan, I'd suspect that the galley sink and second bath sink share a common gray tank, but it's possible that the washer does empty into the black tank.

Do you have a washer connected in your trailer?

Icantdrive55 · 07-28-2020, 09:11 AM

No washer and dryer here, but there's two gray and two black, the kitchen sink and the rear bath sink share the rear gray tank. The black tank filling on its own has only been an issue the last couple of weeks, otherwise I've spent 10 months living in the RV. I just can't for the life of me figure out where the hell the water's coming from, I'm waiting on a reply from keystone as to any possibilities.

travelin texans · 07-28-2020, 09:30 AM

There's 3 water hose connections on the left side of the photo, the way it's labeled & covered by the hose it's very hard to determine which is for fresh water & which may be tank flush connections.
Is it possible that you've connected to the wrong port?
In that photo there's only 1 valve each for black/grey drains, is there another spot for the other 2 tank drains with possibly a port to flush that black tank?
Not familiar with your RV is reason for the questions.

Icantdrive55 · 07-28-2020, 09:31 AM

Quote:

Originally Posted by travelin texans

There's 3 water hose connections on the left side of the photo, the way it's labeled & covered by the hose it's very hard to determine which is for fresh water & which may be tank flush connections.
Is it possible that you've connected to the wrong port?
In that photo there's only 1 valve each for black/grey drains, is there another spot for the other 2 tank drains with possibly a port to flush that black tank?
Not familiar with your RV is reason for the questions.

No worries, from top down it's winterized, freshwater, tank flush. Water is connected correctly.

**JRTJH** · 07-28-2020, 09:39 AM

Just to be clear, is the water coming out of the rear black tank "clean water" or is it "brown water" (not partially stained by previous tank contents)...

In other words, is it "black tank contents" typically seen in black tanks or is it "cleaner water like fresh water leaking into the black tank" ???

Icantdrive55 · 07-28-2020, 09:42 AM

Quote:

Originally Posted by JRTJH

Just to be clear, is the water coming out of the rear black tank "clean water" or is it "brown water" (not partially stained by previous tank contents)...

In other words, is it "black tank contents" typically seen in black tanks or is it "cleaner water like fresh water leaking into the black tank" ???

It's clear water, but if it sits in a tank for a couple days it comes out light brown, just from the residual residue left in that tank when I used to use it.

**JRTJH** · 07-28-2020, 09:49 AM

So, there's obviously a "source of fresh water" migrating to the rear black tank... To my knowledge, there's only one "fresh water connection" and that's the black tank flush fitting... By RVIA requirements, there should be NO interface between the trailer fresh water system and the black tank (other than through the toilet bowl and the fresh water black tank fitting (which is not a permanent connection). It should not be active if there is no garden hose connected to the side of the trailer at that port....

STRANGE PROBLEM.... I don't have any suggestions but sure would like to hear what the final conclusion might be....

**flybouy** · 07-28-2020, 09:54 AM

Quote:

Originally Posted by Icantdrive55

No washer and dryer here, but there's two gray and two black, the kitchen sink and the rear bath sink share the rear gray tank. The black tank filling on its own has only been an issue the last couple of weeks, otherwise I've spent 10 months living in the RV. I just can't for the life of me figure out where the hell the water's coming from, I'm waiting on a reply from keystone as to any possibilities.

Would be interesting to hear Keystone's response. If there were a freshwater source available to fill the black tank then why did it take 10 months to show up? I can't think of a probable cause for that. Hope you find the cause and share it with us.

Icantdrive55 · 07-28-2020, 09:56 AM

Quote:

Originally Posted by flybouy

Would be interesting to hear Keystone's response. If there were a freshwater source available to fill the black tank then why did it take 10 months to show up? I can't think of a probable cause for that. Hope you find the cause and share it with us.

The only thing I can think of, and I have no idea why to flush the black tanks I needed to turn the water heater bypass on, some weird plumbing thing they did and I've got a bad valve somewhere. But that makes me worry where the hell The water is coming from, and if I need to worry about fresh water in the sinks or shower.

**JRTJH** · 07-28-2020, 10:22 AM

Quote:

Originally Posted by Icantdrive55

The only thing I can think of, and I have no idea why to flush the black tanks I needed to turn the water heater bypass on, some weird plumbing thing they did and I've got a bad valve somewhere. But that makes me worry where the hell The water is coming from, and if I need to worry about fresh water in the sinks or shower.

If there is a "direct connection" between the spray head in the black tank and the water heater bypass, then you have a "direct connection" between the black tank and your cold water supply lines to the sink, shower and toilet flush water supply. That would only be "protected" by the anti-siphon valve in the black tank flush water supply line.

Like you, if that is the situation, I'd be extremely concerned with my family's health based on contamination of the fresh water supply in the trailer...

That said, I can't imagine any RV black tank flush that requires the water heater to be in "bypass mode" to flush the black tank.... Are those instructions written down anywhere or are those instructions "passed on by someone to you" ???

Is this trailer previously owned or was it purchased new?

Icantdrive55 · 07-28-2020, 10:24 AM

Quote:

Originally Posted by JRTJH

If there is a "direct connection" between the spray head in the black tank and the water heater bypass, then you have a "direct connection" between the black tank and your cold water supply lines to the sink, shower and toilet flush water supply. That would only be "protected" by the anti-siphon valve in the black tank flush water supply line.

Like you, if that is the situation, I'd be extremely concerned with my family's health based on contamination of the fresh water supply in the trailer...

That said, I can't imagine any RV black tank flush that requires the water heater to be in "bypass mode" to flush the black tank.... Are those instructions written down anywhere or are those instructions "passed on by someone to you" ???

Is this trailer previously owned or was it purchased new?

Brand new trailer purchased last summer, and you can see the picture I posted above, that the chart indicates the bypass needs to be on during tank flush, even though there's a separate water connection

**flybouy** · 07-28-2020, 10:47 AM

The water heater in "bypass" makes no sense to me either as the instructions show that the hose should be connected to the "Tank Flush" inlet and not the "City Water" inlet.

Javi · 07-28-2020, 11:00 AM

I want to know what that is...

Icantdrive55 · 07-28-2020, 11:01 AM

Quote:

Originally Posted by Javi

I want to know what that is...

Lol that's the cover for the freshwater intake

bill-e · 07-28-2020, 07:13 PM

I think the last two valve position drawings are both for winterizing. Notice how the other drawings are centered on Power Fill, Dry Camping and City Water then the next two are both opposite Winterizing. I don't understand why two for winterizing unless you have to winterize the two water paths, from the FW Tank and from the hose (which I would think would be the City Water line)

And, are you sure that the rear toilet flush isn't constantly leaking? It's easy for the toilet flapper to get out of whack and not seal and that might let a leaking flush put clean water into the tank.

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