27U black tank issues

[Dmarcian]

I have a 2023 Greyhawk 27U and have had issues draining the black tank since new. I noticed when I run water into the black tank flush (with the valve open) water doesn’t seem to drain out. And I don’t think my tank is getting fully emptied. I recently read on a different forum about a black tank “vacuum breaker valve”. What is that and what does it do? Thanks.

[pconroy]

Couldn't you test this by turning off the pump, and flushing the toilet while draining? Opening the bottom toilet valve?

[Parrott]

Originally Posted by Dmarcian

I have a 2023 Greyhawk 27U and have had issues draining the black tank since new. I noticed when I run water into the black tank flush (with the valve open) water doesn’t seem to drain out. And I don’t think my tank is getting fully emptied. I recently read on a different forum about a black tank “vacuum breaker valve”. What is that and what does it do? Thanks.

Vacumn breaker valve is to keep black water from siphoning back into the water hose when hooked up for flushing. They can be a pain and some have just taken them out or replaced with a back flow preventer.

[Dmarcian]

Thank you!

[Parrott]

If you ever flush your tank and find water on the floor, most times in the bathroom cabinet where most vacuums are located, it needs replacing. They have a spring inside and it gets weak or stuck allowing water to leak out. Typical picture of valve. Has to be mounted higher than the toilet.

[Grimmy999]

I'm having a hard time understanding exactly what the issue is. Do you think the black tank flush isn't filing the tank, or that the tank isn't draining?

I have a '22 27U and when I have time to flush (meaning I don't have other people waiting to dump) I'll pull the black tank valve and let that drain out. Then close it to let the tank fill back up with water from the flush. This can take a while. Like five minutes. Then pull the valve again. The extra force helps push things along. If I leave the valve open and have the flush going only a trickle will come out. I don't think that flush has a high volume going into the tank.

Also, do note that the Y connector can rotate where the hose attaches. I like to have it angled down more, and not just horizontal the way it comes from the factory.

[mini4mw]

The black and grey tank have vent hoses to the roof, just like in a house, so there shouldn't be a vacuum holding stuff in. If the black isn't draining, could be a clog. Something stuck up there from manufacturing.. snake camera may be best bet.

[Parrott]

Originally Posted by mini4mw

The black and grey tank have vent hoses to the roof, just like in a house, so there shouldn't be a vacuum holding stuff in. If the black isn't draining, could be a clog. Something stuck up there from manufacturing.. snake camera may be best bet.

The vacuum breaker he is asking about has to do with the black tank flushing

[Dmarcian]

Thanks, I may have something in the black tank from manufacturing.

[Parrott]

Originally Posted by Dmarcian

Thanks, I may have something in the black tank from manufacturing.

Sometimes when they cut the hole for the vent pipe, the piece falls inside and if it’s a lazy person they will not fish it out.

[mini4mw]

If there is something in there from manufacturing, it will probably float (plastic, foam insulation, etc). The best non-tech view is down the toilet. I'd fill the black tank 2/3 (5gal bucket several times down the toilet may be faster than holding toilet foot bar), get a broom handle, hiking stick etc and a good LED flashlight and swish around and see if you can find anything floating in there.

It makes sense that it would float as black drains well until it get low. Unfortunately getting it out may be hard as if its not coming out the black tank, which has a 3-4" opening, it may be bigger than any hole to pull out. Hopefully it will just be something you can see down the toilet and use some long pinchers to get out (like the ones they use to pick up trash), or at least get high enough you can grab with your hands and bend/brake it to get it out.

I'm guessing its the cutout for the black tank drain. Most everything else would be smaller than the drain itself and should come out with drain flow.
- assuming its been like this since new -

[billcf7]

Originally Posted by Parrott

Sometimes when they cut the hole for the vent pipe, the piece falls inside and if it’s a lazy person they will not fish it out.

This is my guess what your problem is if its been happening from new

[Marshmellow]

thats how it works the flush is not a high volume of water mostly a jet up near the toilet that just washes away any crap

[cmikal]

Since you indicated it's been doing this since it was new, maybe this......

https://www.youtube.com/watch?v=Wg_X...el=CountryLane

[spark of insanity]

Mine is a preowned and I am also having issues as well. The RV tech said to keep it closed for a week and keep adding water. He did check it a week later and said it may need to be jetted. Meaning cleaning it out completely. I am going to try those chemical things you see at the store. I keep the grey valve open but keep the black valve closed. My sensor says it is full and even after a week the sensor still says full. So if the chemical flush does not work then its jet time. Good luck.

[mini4mw]

Drain it as best you can with the black tank flush and then stick this camera down there as nasty as that is

Limited-time deal: DEPSTECH Dual Lens Wireless Endoscope, 1080P Scope Camera with 7 LED Lights, 0.31In Lens Video HD Inspection Camera, Zoom Waterproof Borescope Semi-Rigid Cable for Android & iOS Phone or Tablet-16.5FT https://a.co/d/cioYDR3

I have this one and have it for other things but I'd use it in this case instead of guessing. I might actually fill black tank up 1/2 way with water as if it is the cut out it might be easier to see floating around.

It's got a good light on it and decent camera. Hardest part is seeing the images right side up and moving forward in that direction. The snake is solid enough to keep position as you move forward but will bend if you hit something.

Seems easier than guessing. If you go down the toilet, turn the water off so it's not running while you're poking around in there

[rodpod]

Originally Posted by mini4mw

The black and grey tank have vent hoses to the roof, just like in a house, so there shouldn't be a vacuum holding stuff in. If the black isn't draining, could be a clog. Something stuck up there from manufacturing.. snake camera may be best bet.

On more than a few occasions the clog turns out to be The bore hole cut out that the moron cut to install the fittings for the black tank pipes. A bore scope a can verify this. Unfortunately, it's damn near impossible to remove. And, it's a messy job. Don't ask me how i know. Poor Jayco quality strikes again. Good luck

[SmokeyBear]

Originally Posted by mini4mw

Drain it as best you can with the black tank flush and then stick this camera down there as nasty as that is

Limited-time deal: DEPSTECH Dual Lens Wireless Endoscope, 1080P Scope Camera with 7 LED Lights, 0.31In Lens Video HD Inspection Camera, Zoom Waterproof Borescope Semi-Rigid Cable for Android & iOS Phone or Tablet-16.5FT https://a.co/d/cioYDR3

I have this one and have it for other things but I'd use it in this case instead of guessing. I might actually fill black tank up 1/2 way with water as if it is the cut out it might be easier to see floating around.

It's got a good light on it and decent camera. Hardest part is seeing the images right side up and moving forward in that direction. The snake is solid enough to keep position as you move forward but will bend if you hit something.

Seems easier than guessing. If you go down the toilet, turn the water off so it's not running while you're poking around in there

I want this! So many times it would have been useful. But (isn't there always a but?) I have a question.

The first video says be sure to get the correct one for the device you will be connecting it to, iPhone, android or other. However, on the Amazon page, I can't find anything about selecting the device version. What am I missing?

[mini4mw]

Which video are you taking about? Perhaps they were talking about the app for your device (apple or Android).

It connects via wifi to phone so all you need is the app for your phone.

Turn the device on, wait 5 sec or so, then the device's said/wireless network shows up in phone settings and you switch to that network. Then open the app and the camera view shows up. You could use any tablet or phone that I know of.

You can take pics and video with it as well. If you need a big screen use ipad or Android tablet.

[SmokeyBear]

Thanks. I didn't realize he was talking about the app. That makes sense.

Product ordered. Tomorrow delivery. Boy, am I ever gonna have fun with my new toy.