Tank monitor says 69%, drains backing up!

[Silver Comet]

I have a 2017 Flying Cloud RB 25 footer. When my gray water tank monitor indicates that the tank is at 69%, the kitchen, shower and bathroom sinks back up. I've flushed the tank and monitor is at 0%.

Using a 6 gal. water can, I dump approx. 20 gallons of water into the tank via the shower and the kitchen sink. When the drains backup the monitor says 69%. I've tested this twice with the same results.

At first I thought the monitor gray water sensor was incorrectly installed, but the tank will take only 20 gallons when it is supposed to hold 35 gallons.

Has anyone else run into this? I thought perhaps there might be a foreign object in the tank that is taking up space but not registering with the monitor.

Any ideas will be welcome!

[dbj216]

Very interesting mystery. I'm afraid I would have to look at the 35 gallon gray tank to find out why water won't drain into it. Has it always been this way since new? Or is it a recent problem? There may be a plumber close by with a "camera" who could explore the drain line and then into the gray tank to see if anything is apparent.

Let's see if someone else has had a similar problem with their Airstream.

David

[SeaLevel]

Are you sure your AS is level, and that the grey tank has been completely emptied before starting your capacity test?

Could something be blocking the drain valve?

[Adventure.AS]

Originally Posted by Silver Comet

I have a 2017 Flying Cloud RB 25 footer. ...

At first I thought the monitor gray water sensor was incorrectly installed, but the tank will take only 20 gallons when it is supposed to hold 35 gallons. ...

My 2017 International 25 RB only has a 24 gal grey water tank. Does your FC have larger tanks? Here is the link to the SeeLevel II monitor manual.

[Tbeck11931]

Originally Posted by Adventure.AS

My 2017 International 25 RB only has a 24 gal grey water tank. Does your FC have larger tanks? Here is the link to the SeeLevel II monitor manual.

Wow! Only a 24 gal grey tank? I’ll have to keep and eye on that when I start searching for a newer Airstream.
That’s terrible for Boondocking.

[Tbeck11931]

Originally Posted by Silver Comet

I have a 2017 Flying Cloud RB 25 footer. When my gray water tank monitor indicates that the tank is at 69%, the kitchen, shower and bathroom sinks back up. I've flushed the tank and monitor is at 0%.

Using a 6 gal. water can, I dump approx. 20 gallons of water into the tank via the shower and the kitchen sink. When the drains backup the monitor says 69%. I've tested this twice with the same results.

At first I thought the monitor gray water sensor was incorrectly installed, but the tank will take only 20 gallons when it is supposed to hold 35 gallons.

Has anyone else run into this? I thought perhaps there might be a foreign object in the tank that is taking up space but not registering with the monitor.

Any ideas will be welcome!

There is a endoscope inspection camera that plugs into your android and or I-phone. I’ve seen it for sale on Amazon but I’m not sure that would help troubleshooting your issue. Seems like it could be a handy little item to have in your toolkit. Anyone use one before?

[AirstreamInc]

Hi Silver Comet,

We're very sorry to learn about the issue you described in your 2017 25' Flying Cloud. Please send me a direct message with your contact information and the last 6 digits of your VIN so we can share it with our Customer Service and Technical Support team.

You can also reach Airstream Customer Service and Technical Support at customer_support@airstream.com

We look forward to helping you get this resolved.

[Rob Cope]

I have a 25 FC 2016 RB. Neither black or gray have ever registered accurately. Just now both are at 0, but I know they must be 1/2 full. I pay no attention to the gauge. Sometimes it does no even turn on. No idea. I look forward to learning what you discover.

[Al and Missy]

According to the plumbing diagram in the 2017 FC manual, the bathroom sink is plumbed to the black tank. I find it odd that it is backing up at the same time as the kitchen sink and shower.

It is also odd that the kitchen sink and shower drain start to overflow at the same time since the kitchen sink is much higher than the shower drain. I would think that if the kitchen sink is backing up because the tank is full, water would be overflowing out of the shower onto the floor. The only way I could see these symptoms happening (and this is a WA guess) is that the tank vent is clogged (or missing) and flow into the tank is compressing air at the top. At some point the tank will not accept more water due to the air pressure.

Al

[Rob Cope]

I believe the bathroom sink drains into black.

[Al and Missy]

Originally Posted by Adventure.AS

My 2017 International 25 RB only has a 24 gal grey water tank. Does your FC have larger tanks? ...

Odd. Not according to the manual online.

Al

[dznf0g]

Is there a single vent stack? This sounds like a plugged black/gray vent stack to me...or it was installed too far down into the tank(s).

[Adventure.AS]

Originally Posted by Al and Missy

Odd. Not according to the manual online.

Al

Thanks. I stand corrected, I was reading the spec sheet for my previous 22' Sport. Duh!

25'
* Fresh Water Tank (gal.) … 39
* Gray Water Tank (gal.) … 35
* Black Water Tank (gal.) … 37

[Silver Comet]

Originally Posted by dbj216

Very interesting mystery. I'm afraid I would have to look at the 35 gallon gray tank to find out why water won't drain into it. Has it always been this way since new? Or is it a recent problem? There may be a plumber close by with a "camera" who could explore the drain line and then into the gray tank to see if anything is apparent.

Let's see if someone else has had a similar problem with their Airstream.

David

Thanks for your response! We took a 1-week trip last year, and a few weekend trips without this issue. Then again, on our 1-week trip we usually dumped the gray water every other day. And on the weekend trips it was usually just my wife and I. (The gray water tank mystery occurred last weekend when we had 3 people.)

I'm wondering if the air vent pipe to the gray water tank has somehow gotten blocked and the tank has air trapped in it, meaning additional water can't get into the tank because the air can't get out.

[Silver Comet]

Originally Posted by SeaLevel

Are you sure your AS is level, and that the grey tank has been completely emptied before starting your capacity test?

Could something be blocking the drain valve?

I made sure that the AS is level and the tank was completely empty before I started my test.

I don't think it's the valve because the monitor shows 0% after I drain the tank. Also, I took the valve assembly apart thinking I might be able to peek into the tank and see if there was an "unknown object" that got in at the factory. (I was not successful.) The valve was clear.

[Silver Comet]

Originally Posted by dznf0g

Is there a single vent stack? This sounds like a plugged black/gray vent stack to me...or it was installed too far down into the tank(s).

I was also thinking the vent stack might be blocked and that air is trapped in the tank.

Great minds think alike!

[Silver Comet]

Originally Posted by Al and Missy

According to the plumbing diagram in the 2017 FC manual, the bathroom sink is plumbed to the black tank. I find it odd that it is backing up at the same time as the kitchen sink and shower.

It is also odd that the kitchen sink and shower drain start to overflow at the same time since the kitchen sink is much higher than the shower drain. I would think that if the kitchen sink is backing up because the tank is full, water would be overflowing out of the shower onto the floor. The only way I could see these symptoms happening (and this is a WA guess) is that the tank vent is clogged (or missing) and flow into the tank is compressing air at the top. At some point the tank will not accept more water due to the air pressure.

Al

I realized that the bathroom sink drains into the black tank after I made my original post, so my bad on that one.

I also thought it that there would be a lot more water backed up in the shower due to the kitchen sink being much higher. There was some, but not as much as I thought there would be.

I'm really leaning towards air being trapped in the tank.

[dznf0g]

Whe you have a backed up event, do you get a puff of foul air if you flush the toilet, followed immediately with the sink and shower draining? Careful, or you may get a face full....start the experiment with no water in the bowl. An alternative experiment would be to hold the toilet valve open and try and fill the gray tank to 100% on your gauge. Shut off the water supply behind the toilet.
Again, does your unit have a single stack which vents both black and gray?

[Silver Comet]

Turns out my Flying Cloud had two problems:
1) Tank level monitor showed 69% when tank was full,
2) Tank held approx. 24 gallons when it should have held 35 gals.

The solutions:
1) Tank sensor was replaced by the dealer.
2) The tank vent pipe was 10 inches too long and extended too far into the tank. When the water level reached the pipe (at about 24 gals.) the end of the pipe was blocked, meaning that additional water couldn't enter because the air couldn't get out.

Dealer raised the pipe, cut off the excess material and reinstalled. Tank now holds 34 gallons and monitor reads 100%. Success!!

Thanks everyone for their suggestions and ideas...

[pcskier]

Originally Posted by Silver Comet

2) The tank vent pipe was 10 inches too long and extended too far into the tank. When the water level reached the pipe (at about 24 gals.) the end of the pipe was blocked, meaning that additional water couldn't enter because the air couldn't get out.

Dealer raised the pipe, cut off the excess material and reinstalled. Tank now holds 34 gallons and monitor reads 100%. Success!!

Unbelievable. All this hassle because someone at the factory just stuffed the too-long pipe into the hole rather than take 1 minutes to cut it. But at least you GOT one. Someone recently posted about odor in their new trailer, and when they looked behind the wall, the vent pipe wasn't even there.