2019 Grand Design Imagine 2150RB black tank check valve

jetchill

New Member
Joined
Nov 7, 2018
Messages
9
Location
Brownstown MI
When I connect hose to black tank flush port, water starts leaking from rear of trailer. Grand Design Tech says it check valve. Problem is they don't know where it is at and can't tell me how to get to it.
I looked behind shower faucets, under shower stall and under sink. Cutting into wall is next suggestion from GD Tech and he is guessing. Anybody experience this problem ?
 
I would check for a leak/break/loose something at the black tank, to see if anything is causing the leak. A check valve should only let it flow back to the input port not leak. So my thinking would be the above.

An option of dropping the lower covering, maybe get or borrow a boor scope to check it out. A long scope might find the problem putting it in the piping going from fresh to the grey tank.
 
I would check for a leak/break/loose something at the black tank, to see if anything is causing the leak. A check valve should only let it flow back to the input port not leak. So my thinking would be the above.

An option of dropping the lower covering, maybe get or borrow a boor scope to check it out. A long scope might find the problem putting it in the piping going from fresh to the grey tank.
Good information, makes a lot of sense.Where is the water leaking out from ? Hoping to hear from someone who experienced same problem on similar RV. Hitting the road next month, if I don't come up with anything by then, I will wash out by pouring water into toilet and not use outside flush port.
 
The outside flush port is completely useless anyway. I only use mine to measure 8 gallo a of water to go back into the holding tank after I flush the system using a wand through the toilet

I bet you will be very very surprised how much stuff dumps out after you use a toilet wand instead
 
The vacuum breaker for the black tank flush is often located behind the shower faucet (it has to be higher). Look for a panel in the linen closet behind the shower faucet.

I disagree with the statement about the black tank flush being "completely useless." It helped us keep our black tanks clean and the sensors working during our nine years of full-timing.

Rob
 
The vacuum breaker for the black tank flush is often located behind the shower faucet (it has to be higher). Look for a panel in the linen closet behind the shower faucet.

I disagree with the statement about the black tank flush being "completely useless." It helped us keep our black tanks clean and the sensors working during our nine years of full-timing.

Rob
I agree with your disagree. :)
 
Keep in mind, the black tank flush has a vacuum breaker, not a check valve. And for it to work, it must have an opening to the atmosphere. It is not uncommon for a tiny quantity of water to escape when water pressure if first applied, but never a gush of water. That would indicate a problem with the breaker or perhaps an obstructed outlet. Also, to work as intended, it must be position a distance above the toilet rim set by code - I think 18” minimum. Mine is located behind a drawer in the bedroom wardrobe. And one last point, it is dangerous to replace this breaker with ANYTHING other than another breaker!
 
The vacuum breaker for the black tank flush is often located behind the shower faucet (it has to be higher). Look for a panel in the linen closet behind the shower faucet.

I disagree with the statement about the black tank flush being "completely useless." It helped us keep our black tanks clean and the sensors working during our nine years of full-timing.

Rob
I looked behind shower faucet, No Luck not there. There is a tight 8 inch space (linen closet) between shower stall and end of trailer along side of toilet, no access without cutting. Seems like a logical place for check valve or leak.
I hope to get confirmation from some one that actually had this problem or knows for sure Im doing the right thing before I cut into that linen closet
 
Keep in mind, the black tank flush has a vacuum breaker, not a check valve. And for it to work, it must have an opening to the atmosphere. It is not uncommon for a tiny quantity of water to escape when water pressure if first applied, but never a gush of water. That would indicate a problem with the breaker or perhaps an obstructed outlet. Also, to work as intended, it must be position a distance above the toilet rim set by code - I think 18” minimum. Mine is located behind a drawer in the bedroom wardrobe. And one last point, it is dangerous to replace this breaker with ANYTHING other than another breaker!
Can't think of anyplace that could be 18 inches above toilet rim except for shower faucets and its not there. That 18 inches is new information. Thank You
 
I looked behind shower faucet, No Luck not there. There is a tight 8 inch space (linen closet) between shower stall and end of trailer along side of toilet, no access without cutting. Seems like a logical place for check valve or leak.
I hope to get confirmation from some one that actually had this problem or knows for sure Im doing the right thing before I cut into that linen closet
I've never encountered a unit that didn't have a panel for access to the vacuum breaker - wherever it is. Doesn't meant there isn't one out there. Perhaps @huntr70 can help us out regarding your model.

Rob
 
I've never encountered a unit that didn't have a panel for access to the vacuum breaker - wherever it is. Doesn't meant there isn't one out there. Perhaps @huntr70 can help us out regarding your model.

Rob
I wish my memory was that good....they haven't built the 2150 for at least 3 years.
 
When I connect hose to black tank flush port, water starts leaking from rear of trailer. Grand Design Tech says it check valve. Problem is they don't know where it is at and can't tell me how to get to it.
I looked behind shower faucets, under shower stall and under sink. Cutting into wall is next suggestion from GD Tech and he is guessing. Anybody experience this problem ?
I had the same issue with my 2018 unit. Valve is found in linen cabinet next to shower. Bottom panel has two screws. Remove and lift up. Valve is right there and Amazon or rv shops carry. Easy fix.
 
Here's a picture of the rear of the trailer exposed
 

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I had the same issue with my 323bhs. I found the Black flush valve going into the tank was cracked. The only time it leaked was when I flushed the tank. It’s a fairly easy repair.
 
In my experience the rv style vacuum breakers are junky valves. I have ad two of them fail.... one was full of bugs and wouldn't close. I made a screen and never had a problem again. The second and third ones occasionally leaked when connected because the plunger doesn't move straight.

As @Rabbitt said, the vacuum breaker must be above the rim of the toilet (highest unvented part) although I think I read twelve inches.

I moved mine to the wet bay. It is about sixteen inches above the tank. Although this is not above the toilet, there are other problems with the factory location anyway. Now I don't worry about a slow or intermittent leak going unnoticed. And... I can also see how junky they are. After three or four months on a new valve, maybe every third or fourth time connecting, it will leak. And the floor under where it used to be is finally dry.
 
I had the same issue with my 2018 unit. Valve is found in linen cabinet next to shower. Bottom panel has two screws. Remove and lift up. Valve is right there and Amazon or rv shops carry. Easy fix.
Same here but we have a 2018 2600RB. Bottom shelf in linen closet behind toilet, next to shower had a screw hidden behind face trim. I keep this backed out 1/2 way now and just lift the cover off, it is just a removable 'shelf' on top of the actual shelf with the cutout. You can see the hose running from outside wall into the valve. Quick 5 minute replacement for the vaccuum breaker valve. I also had to disconnect and blow the line out that then leads from vaccuum breaker to the black tank. The spray valve in tank was clogged. I dropped the back part of the underside chloroplast to expose where it went into tank to replace spray valve. But before replacing it, I tried just hooking up air compressor to the outflow hose of vaccuum breaker valve and it took 100psi to blow them out clean. It's a heavy duty hose and clamp and caused no issues blowing that much pressure through.

Even after dumping four 5 gallon buckets of water down the toilet to rinse, we still get a good amount of debris out of black tank using the black tank flush.
 

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