black water clean out connection leaks

[OldRacer]

2016 Passport Ultralite 2770. Maiden voyage was this past weekend. Everything worked but 2 items.

1. Found out if you leave the bathroom door open, it blocks the intake vent for the furnace and apparently the furnace somehow overheats and when it shuts down, takes several hours to start back. Couldnt for the life of me figure out what was going on, thought maybe the tstat was messed up, but once we kept the bathroom door closed, unit worked perfectly the rest of the weekend.

2. And this one is what this thread is about.

Decided to dump and flush the blackwater tank there at the campground before we left since they had full hookups and i knew i wouldnt be holding anyone up while i flushed the tanks clean USING THE BUILT IN FLUSH SYSTEM. As per the picture attached, the hose comes from the outdoor fitting into the bathroom under the sink. It turns up and goes thru some sort of vent thingy (i have no idea what this is and this is the part that is leaking) then goes out and down to the black tank.

Just what the heck is this thing, (i'm assuming its some sort of vent altho i cant figure why it would be needed.) And surely its not supposed to be leaking out the TOP of it. The screw on fittings are tight, and the fittings themselves are not leaking. Its spraying out from under the top of the square plastic vent looking thing.

I'm tempted to just do away with this and install a 90 degree fitting there so it goes straight down to the black tank, but would like to know if its needed, and if its not supposed to be leaking (which its not), then i'll call the dealer i bought it from and get them to send me a new one.

[OldRacer]

evanvalk wrote:
Others have told me they had a leak problem only if they turned the hose on while the black tank cap was locked on.

yea, i tried it both ways, with the valve close and open. Leaked both times.

Problem is solved now.

[evanvalk]

Others have told me they had a leak problem only if they turned the hose on while the black tank cap was locked on.

[Old-Biscuit]

hohenwald48 wrote:
I think I will. I tried our flush connection once and it leaked so I just stopped using it. I'm not too fanatical about tank cleaning anyway. I just flush the toilet with a reasonable amount of water when it's used and I haven't had a problem in over 25 years (10 of them full time) of owning an RV.

My father in law is one of those who flushed his black tank with the valve closed, got distracted and about a thousand gallons later had a real mess inside.

Same here....they are just holding tanks
Fill them dump them......done

[hohenwald48]

I think I will. I tried our flush connection once and it leaked so I just stopped using it. I'm not too fanatical about tank cleaning anyway. I just flush the toilet with a reasonable amount of water when it's used and I haven't had a problem in over 25 years (10 of them full time) of owning an RV.

My father in law is one of those who flushed his black tank with the valve closed, got distracted and about a thousand gallons later had a real mess inside.

[Old-Biscuit]

hohenwald48 wrote:
Will it leak fresh water from the hose or dirty water from the tank?

Looks to me like it will leak a bit of dirty water from those holes marked "air inlet" in the drawing. Maybe even more than a little if it's below the level of the holding tank and gets a siphon action started via those "air inlets".

It will leak clean water from the section of flush system right at the connection 'check valve' which is part of the hookup......spitz then nothing

The air holes break any vacuum that would allow siphoning IF the check valve in the connection doesn't close. Remember the flush line goes to a open nozzle that won't suck anything from the black tank unless tank was FULL FULL FULL, check valve stuck open and vacuum breaker air holes were plugged---------and then where is it going to go with water supply hose bib closed (if it was open water pressure would push water into system not allow if back out)

Really is a lot of woo--ha (much ado about nothing)

For $5 pick one up and give it a try

[hohenwald48]

Will it leak fresh water from the hose or dirty water from the tank?

Looks to me like it will leak a bit of dirty water from those holes marked "air inlet" in the drawing. Maybe even more than a little if it's below the level of the holding tank and gets a siphon action started via those "air inlets".

[Old-Biscuit]

hohenwald48 wrote:
I think I see what you mean. I wonder why the manufacturers wouldn't just do that in the first place? Seems it would be cheaper than the valve they install under the cabinet.

Because of 'code'---'standards' RV MFG. must meet.

Anti-siphon vacuum breaker required in potable water/contaminated water connections.
The current device used is not suppose to leak when properly functioning



The hose end vacuum breaker WILL leak each time water supply is secured.......by design

[OldRacer]

Yep, that part was a whopping $5 from Ace Hardware.

[hohenwald48]

I think I see what you mean. I wonder why the manufacturers wouldn't just do that in the first place? Seems it would be cheaper than the valve they install under the cabinet.

[OldRacer]

Yep, works exactly the same.

The male threaded end screws into the port on the exterior of the RV leaving the female side of the bib to screw the hose into, which is the correct way for flow and it keeps anything from coming out of rv into garden hose.

[Old-Biscuit]

hohenwald48 wrote:

OldRacer wrote:
just solved the problem today.

straight thru inside the RV replacing the vent/check valve and put a vaccum break check valve on the outside. It screws onto the hose and then into the opening of the trailer. Does the exact same thing.

I don't think it does the same thing. The original was in place to prevent waste tank contents from siphoning from the tank and out thru the garden hose.

The one you installed (assuming it's a hose bib vacuum breaker like you would use on your house) is designed to keep the contents of the garden hose from siphoning back into the waste tank (house). It will allow waste tank contents to siphon out thru the garden hose and into the public water system.

When connected to hose bib (cg) water can only flow away from hose bib and when you turn hose bib off vacuum breaker allows water in hose to depressurize.

Now if you install it at other end of hose vs hose bib water will still only flow away from hose bib and when you turn water off vacuum breaker will still allow the little bit of water at RV connection to depressurize and then the check valve inside the flush connection will close

Hose bib vacuum breaker is going to work the same regardless of which end of hose it is on.

[hohenwald48]

OldRacer wrote:
just solved the problem today.

straight thru inside the RV replacing the vent/check valve and put a vaccum break check valve on the outside. It screws onto the hose and then into the opening of the trailer. Does the exact same thing.

I don't think it does the same thing. The original was in place to prevent waste tank contents from siphoning from the tank and out thru the garden hose.

The one you installed (assuming it's a hose bib vacuum breaker like you would use on your house) is designed to keep the contents of the garden hose from siphoning back into the waste tank (house). It will allow waste tank contents to siphon out thru the garden hose and into the public water system.

[Old-Biscuit]

hohenwald48 wrote:
If the water (fresh) is connected to the bottom in the illustration, then when the water pressure is removed and the plunger drops down, isn't the black tank now venting underneath the bathroom cabinet (or wherever it's mounted)? :E

Yes with the cheap ones it can.........fortunately the openings in the spray nozzle are relatively small and odors don't build up much due to the larger open venting to roof.

[OldRacer]

just solved the problem today.

straight thru inside the RV replacing the vent/check valve and put a vaccum break check valve on the outside. It screws onto the hose and then into the opening of the trailer. Does the exact same thing.