Black Tank Flush Leak

MNtabernacle

Just in case anyone else sees this problem, we were seeing leakage on the underside of our 400 during black tank flushing, plus a strong tank smell in the bathroom at all times. Due to some great detective work by our dealer (Elk River RV - Thanks guys!) they found a broken flush check valve (allowing flush water and gas out) and were able to replace it by removing the outside shower and reaching in.

That said - we're always reminded to keep the fresh water pressure under 50 psi - should this apply to the flush as well? It isn't marked as such but I can imagine it could damage the flush system.

Thoughts anyone??

Verna

I do use the black tank flush every opportunity I get. I was wondering about the pressure last weekend when I flushed the tank (I’m in a full services RV Park near where I have spent most of my summer).

I think that I will put a pressure regulator on my black hose (it really is black) to keep the pressure down within acceptable limits. I don’t feel I can trust my own definition of how many turns of the faucet it takes to stay below 50 lbs, so I’ll let a known pressure relief valve keep me within the limit of 50 lbs psi, even though there is nothing indicating that I must keep the pressure within those limits.

I think it makes sense to keep all incoming water pressure at or  below 50 psi. 

MNtabernacle

Verna, when you are at a spot with full hookups, and want to do a black tank flush, the flush hose needs to hook up to the potable water supply. Do you feel there is a chance of contaminating that spigot with your flush hose?

Verna

@MNtabernacle, no, I do not feel there is a chance of contamination. I do use a dedicated hose, and I use a “y” at the campground faucet. 

Sharon_is_SAM

Some owners spray a spigot with bleach before connecting just to ward off evil spirits.  Not a bad practice.

Verna

Those of us who are allergic to bleach can always use vinegar in its place. 

N7SHG_Ham

The faucet is the same, black tank or fresh water connection. I always wonder what the last camper did?

Most of us use a separate hose, but do we consider yuk transfer to the faucet, the pressure regulator, the "y" and so on?

My guess is there is a lot of yuk spread around the hookup side and on the faucet at every CG.

If one end of black house is yucky, what prevents the "clean" end and associated things it touches from being yucky?

4ncar

Bah...im a backpacker...everything is just “flavor crystals!” Lol

jgram2

I’m a retired nurse. That which does not kill us only makes us stronger. If I really wanted to worry, I’d never wear slacks/jeans and use a public restroom-ewwww, can’t keep the pants legs off the floor, ewww. 

N7SHG_Ham

@jgram2 no such thing as the 5" rule in a medical lab, it touches the floor, it is trash!

jgram2

Oops, @N7SHG_Ham. While at work, believe me, I employed all appropriate precautions for my patients and myself. While at play, let’s just say I’m a bit more casual-careful not to contaminate things others use as much as possible but for myself, my tolerance for risk is fairly high. Do I like lying on the ground at the dump site to reach the black tank valve under the Outback platform? Nope, but if I allow myself to really think about what gets on my person, I probably wouldn’t be camping.

Michigan_Mike

MNtabernacle said:

Just in case anyone else sees this problem, we were seeing leakage on the underside of our 400 during black tank flushing, plus a strong tank smell in the bathroom at all times. Due to some great detective work by our dealer (Elk River RV - Thanks guys!) they found a broken flush check valve (allowing flush water and gas out) and were able to replace it by removing the outside shower and reaching in.

That said - we're always reminded to keep the fresh water pressure under 50 psi - should this apply to the flush as well? It isn't marked as such but I can imagine it could damage the flush system.

Thoughts anyone??

Is the flush valve you are referring to hooked to the actual nozzle spray assembly in the black tank?  I guess I thought that the inner nozzle assembly just allowed the water pressure applied to power wash the interior of the black tank?  

As for the yuck stuff, this is why I use the disposable gloves for this task.  I’ve seen people performing the task bare handed and slopping things around in the process.  No different than the guys I see in Sams Club who use the facilities and then head out to the food sample tables without washing their hands.  Nuff said!  😂

Horigan

Given that the flush circuit is open to the black water tank and vented, you can't build 50 psi pressure in that line, even if the pressure at the spigot was well over 50 psi.  There is significant pressure drop just across the spigot valve, with the down stream side being close to atmospheric pressure.  Thus, I wouldn't worry about putting a pressure regulator on when flushing the black water tank.

lpanthers

I have the same leakage problem with my black tank flush system.  There is leakage under our 2020 Tab 400 BDL when I flush/rinse the black tank.  Is this an easy do it yourself fix or do I need to take it to a dealer for repair?
Thanks for any replies.

Lee S
Pisgah Forest, NC
2020 Tab 400 BDL
2014 Toyota Tundra Crew Cab 5.7L

Denny16

The the black tank flush check valve keeps Yuk from the tank from getting in the flush hose, let alone getting back up the hose against the lube pressure to the faucet.
cheers

Sharon_is_SAM

@Ipanthers - I would email Austin in repairs@nucamprv.com and explain your problem.  You can remove the outside shower yourself - lots of pictures on the forum.