Black tank flush check valve

[RWP]

Does anyone know where the blank tank flush check valve (vacuum break) is located on a 2020 sunset trail 291rk?

[Russb]

Mine is in the cabinet under the bathroom sink.

[dagst1]

Usually it is under the bathroom sink way up high. If you replace it I recommend a brass one.

[Papa-T]

Yea mine is under bathroom sink as well.

[Yakherder]

On the inside of the trailer find where the Flush Line comes in. Follow along the line and the Flush Valve will be on there. Mine is also under the bathroom sink but depending where your black water tank is located the Flush Valve could be located anywhere. Let us know where you found it.

[toolman.dustin]

Originally Posted by RWP

Does anyone know where the blank tank flush check valve (vacuum break) is located on a 2020 sunset trail 291rk?

You're probably looking for this thinggoogle this string): RV Vacuum Breaker Check Valve | Protect Fresh Water from Pollutants 571-VAC-CHK-A

Shop around, prices vary.

Mine was located on the inside of the trailer opposite from where my black tank flush inlet (where my garden hose connects to my black tank).
Last winter the valve got stuck closed and would not allow water to fill/flush the black tank and of course the slinger would spin. I removed it (very easy, but difficult to get to the valve ).

I removed the vacuum breaker (photo below) I couldn't blow air into the inlet but the vacuum breaker did work when I sucked air at the inlet. I couldn't get air flow either direction at the outlet. (rinse it in alcohol or bleach before sucking on it).

It was very easy to disassemble the vacuum breaker/check valve. Turns out the check valve is a rubber ball (not plastic). It was "stuck" against the seat it rides against. It was stuck firmly enough it had the imprint of the seat into the ball. Not sure why or how that can happen. The "instructions" that come with a new breaker say not to leave it under pressure for more than 12 hours or the ball can get stuck. Water pressure from the inlet should move the ball forward away from the seat and compress the spring. For the ball to be stuck in the seat, by deforming the rubber ball, pressure would have to be coming from the black tank. I'm not sure how that would happen, but it did. I got the ball unstuck so re-installed it and it's been working fine since.

Here's a photo. Chances are you can un-stick it.
best of luck,
Dustin

[Yakherder]

I think I may have had the same problem with mine some time ago and just replaced it. They can get a bit expensive for just plastic, spring and rubber ball but it is needed. I didn't realize they could be taken apart.

From looking at your picture, it looks like the only pressure on the ball comes from the spring. I guess if the ball sat there long enough it may seal itself to the inlet hole. Minerals from the water that had gone through it can build up and the heat of the summer may add enough gunk to the outside of the ball that it adheres to the opening. I wonder if a shot of silicone spray once and awhile into the outside hose adapter would work at keeping it lubricated. Or if the valve is accessible to just unscrew the inlet and spray the inside.

[toolman.dustin]

Originally Posted by Yakherder

I think I may have had the same problem with mine some time ago and just replaced it. They can get a bit expensive for just plastic, spring and rubber ball but it is needed. I didn't realize they could be taken apart.

From looking at your picture, it looks like the only pressure on the ball comes from the spring. I guess if the ball sat there long enough it may seal itself to the inlet hole. Minerals from the water that had gone through it can build up and the heat of the summer may add enough gunk to the outside of the ball that it adheres to the opening. I wonder if a shot of silicone spray once and awhile into the outside hose adapter would work at keeping it lubricated. Or if the valve is accessible to just unscrew the inlet and spray the inside.

The inlet of the device is on the bottom. The outlet is on the side. The device must me mounted square side up and a few inches above the garden hose inlet. Mine was about 10" above the garden hose inlet.

Silicone spray sounds like a good idea. In my case, spraying silicone into the garden hose inlet would probably not not make it to the device. As long as the ball isn't already stuck, perhaps some spray might coat the ball. Disassembly, pull out the little white insert and the spring (and ball) come out. As to why/how the ball get's stuck is a mystery to me. The inlet water pressure moves the ball away from the seat and compresses the spring. However, the instructions that come with it say not to keep the inlet under pressure for more than 12 hours or the ball can get stuck. 12 hours of inlet pressure would surely overflow the black tank. Pressure from within the black tank can compress the ball into the seat. But, I don't know how the black tank would come under pressure. So, it's a mystery, but it's relatively easy to fix. Yes, $25 for a little piece of plastic is ridiculous expensive.

Dustin

[dagst1]

This is what came in my camper so I replaced it with the same. https://www.amazon.com/San-T-Flush-B...pb_opt?ie=UTF8. So far so good.

[Russb]

Originally Posted by dagst1

This is what came in my camper so I replaced it with the same. https://www.amazon.com/San-T-Flush-B...pb_opt?ie=UTF8. So far so good.

I replaced the san-t-flush with with a hose fitting check valve installed outside the RV at the fill connection. I had the original fail a couple of times and flood the inside of the RV.

[Wingerdinger]

I recommend a brass replacement, and the Watts brand for reliability.
This item has recently come way down in price. I saw it at $60.
I first bought a cheaper one, and it leaked on me.

https://www.amazon.com/Watts-Technol...39546384&psc=1

[RWP]

Originally Posted by RWP

Does anyone know where the blank tank flush check valve (vacuum break) is located on a 2020 sunset trail 291rk?

I found it right behind where the flush water line connects. I had to take a small panel inside the storage area off to get to it. Water pouring out from under the valve cover.

[RWP]

Thanks. Once I found it I took apart but the ball was not stuck. But I don't see how this ever worked as once the pressure pushes the ball off of the spring, water is open to come out the top square piece, which is what it was doing. I will replace with a brass one.

[Yakherder]

Sounds like water froze inside and cracked the housing. I've had that happen here in Manitoba where it gets to -35F/C in winter. Not sure how cold it gets in Georgia but all it takes is for the temps to drop low enough to freeze. I take mine off and clean it out as part of my winterization and reinstall in the Spring. OR the plastic just gave up the ghost.

[Papa-T]

Had to replace mine this year. Started leaking when using tank flush. Took longer to order it than to install. Lol

[robert66r]

Originally Posted by RWP

Does anyone know where the blank tank flush check valve (vacuum break) is located on a 2020 sunset trail 291rk?

Mine is under the bathroom sink. Lol I had to go look for myself for piece of mind.