Newbie question (black tank flush)

Seththel · 10-02-2017, 04:36 PM

I emptied my black tank for the first time today. When I connected the water to the flush it was leaking. The tank filled but it seemed to take a long time. Everything I've read notes about 5 minutes. I waited 8 but I didnt want to have any mishaps so I went ahead and pulled the valve.

Any thoughts or advice would be appreciated.

Thanks

**chuckster57** · 10-02-2017, 04:51 PM

Welcome to the forum

Where exactly was it leaking? Black tank size and water pressure will affect how long it takes to "fill" the tank.

Tbos · 10-02-2017, 05:02 PM

Mine will take longer than 5 min to fill from the flush. I pull the handle first with the flush running. After about 10 min I will close the handle let it fill for 5 min and then repeat it several times. I do have a 40psi regulator on the flush line and an extra back flow preventer too. Never ever let anyone or anything distract you while flushing your black tank. If you do, a stinky mess is around the corner.

2016 Passport GT 2810BHS, 2016 F350 CC DRW

bobbecky · 10-02-2017, 05:02 PM

Our black tank is 53 gallons, so it would take a long time to fill, but when adding water with the valve closed, I usually wait about 5 minutes before pulling the valve, not expecting it to be full, just wanting to clear the line. Smaller tanks of course would take less time.

**JRTJH** · 10-02-2017, 05:10 PM

Quote:

Originally Posted by Seththel

I emptied my black tank for the first time today. When I connected the water to the flush it was leaking. The tank filled but it seemed to take a long time. Everything I've read notes about 5 minutes. I waited 8 but I didnt want to have any mishaps so I went ahead and pulled the valve.

Any thoughts or advice would be appreciated.

Thanks

As a "noobie" I don't know what you "know" and what you "don't know" so this may seem elementary, but needs to be said: If you close your dump valve with the black tank flush system filling the black tank, you run the risk of damaging the tank. Many of us do it, but you must realize that with the valve closed and water running into the tank, once it's full, the water has to go somewhere. We all "think and hope" that if it ever happens to us that the water will rise in the vent pipe and flow onto the roof of the RV. BUT the other possibility is that it will rupture the black tank, spilling the contents into the basement area, destroying (contaminating) the insulation and all the wiring, heat ducting, plumbing and anything else that's under your floor and above the black plastic sheet that covers your trailer's "belly".

So, leave it running for a period of time and you do run the risk of damaging your equipment. Do so with the understanding that it's a nasty, expensive repair.

The system is designed to flush the black tank with the valve open and there's a warning in the operating instructions that states not to close the valve with the black tank flush system in operation. We all "do it" but we also "run the risk" of damaging our black tank...

If you already knew this, then disregard.....

**chuckster57** · 10-02-2017, 05:14 PM

Quote:

Originally Posted by JRTJH

As a "noobie" I don't know what you "know" and what you "don't know" so this may seem elementary, but needs to be said: If you close your dump valve with the black tank flush system filling the black tank, you run the risk of damaging the tank. Many of us do it, but you must realize that with the valve closed and water running into the tank, once it's full, the water has to go somewhere. We all "think and hope" that if it ever happens to us that the water will rise in the vent pipe and flow onto the roof of the RV. BUT the other possibility is that it will rupture the black tank, spilling the contents into the basement area, destroying (contaminating) the insulation and all the wiring, heat ducting, plumbing and anything else that's under your floor and above the black plastic sheet that covers your trailer's "belly".

So, leave it running for a period of time and you do run the risk of damaging your equipment. Do so with the understanding that it's a nasty, expensive repair.

If you already knew this, then disregard.....

Try being the guy that gets that job!! My SECOND day as an RV tech: had to change black tank valve seals. Owner never rinsed the tank and it was piled up to the base of the toilet.

**JRTJH** · 10-02-2017, 05:23 PM

Definitely not a job I'd want to do !!!

CrazyCain · 10-03-2017, 12:56 AM

Thats just plain nasty Chuckster57, think they saved that one for you as an initiation!!

**chuckster57** · 10-03-2017, 02:43 AM

We do make sure the new guy gets the next one.

PARAPTOR · 10-03-2017, 04:54 AM

Just wondering what you could have done to deserve that JOB

**chuckster57** · 10-03-2017, 07:05 AM

Quote:

Originally Posted by PARAPTOR

Just wondering what you could have done to deserve that JOB

I got hired.

texas-traveler · 10-04-2017, 11:23 AM

black tank flush!!!!! DON"T GET DISTRACTED
Just think of the movie with Robin Williams. Vacation. with the big motor home
In my past club we had several members at rallies(newbies) that would start the flush process with the valve closed. Had gotten side tracked and walked away. The black tank actually filled up and blew liquid out the top of the rv through the tank vent on the roof.Now that was a mess.
If this happens, Remember don't open the toilet valve until the tank is empty. it will blow back through the toilet also. can plug up the tank vent also.

IRV2 · 11-05-2017, 05:51 PM

I tried to use my black flush today. Just for the record the black flush and winterizer inlets are not marked and are located next to each other. I was told that the black flush was marked because the warning sticker is under the inlet. When I connected the water to to inlet that had the warning sticker under it and turned the water on slightly it shot back out of the inlet as if it was closed. What did I do wrong? Is there a valve behind the access panel in the cargo area? Or maybe its mislabeled like the grey and black tanks valve handles were. Any help on this is much appreciated.

**chuckster57** · 11-05-2017, 06:12 PM

If it shot back out of the part you thread the hose onto, look at the fitting and make sure there is a screen/washer there.

MattHelm21 · 11-05-2017, 08:22 PM

Quote:

If it shot back out of the part you thread the hose onto, look at the fitting and make sure there is a screen/washer there.

Exactly what I was going to suggest. I’ve got that t-shirt except I was trying to pull antifreeze into an inlet without a gasket/screen and couldn’t figure out why it wouldn’t pull it in.

**sourdough** · 11-06-2017, 09:12 AM

Quote:

Originally Posted by IRV2

I tried to use my black flush today. Just for the record the black flush and winterizer inlets are not marked and are located next to each other. I was told that the black flush was marked because the warning sticker is under the inlet. When I connected the water to to inlet that had the warning sticker under it and turned the water on slightly it shot back out of the inlet as if it was closed. What did I do wrong? Is there a valve behind the access panel in the cargo area? Or maybe its mislabeled like the grey and black tanks valve handles were. Any help on this is much appreciated.

Another possibility is a faulty or backwards vacuum break/backflow preventer. That's exactly what mine did the first time I used it and the dealer had to repair it. It's worked perfectly since.

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