How do you know it's full?

[Montana_2825]

When you are OUTSIDE the RV filling the black water tank to flush it with clean water, how do you know when it is full? I know I can monitor the panel inside (or have my wife do it), but what method do you use when outside and alone?

wingnut

[CountryGuy]

wingnut,

I would NEVER trust that inside monitor panal thingy! NEVER! IF she is gonna monitor something, have her stand in the toilet area and watch for overflow. At least as good a way to tell if you are full, well, no, better! Monitors rarely work!

I think Steve R has timed his. So many minutes, turn it off.

I am sure some other MOC members will come along and give you very good answers to this question.

Carol

Al would like to remind you that it says to NOT plug the holding tank while rinsing, always keep the valve to the black water tank open. He says it says that on the unit by the filler hose.

[illapah]

are you using the built in flush or filling thru the toilet?

If I understand the manual, if using the built in flush you do not close the tank valve when flushing. I leave it open on mine.

[padredw]

The warning that the black tank emptying value must be open when using the flush connection is prominently displayed on my Montana

[Montana_657]

Place wife on "throne".... turn on flush.... close handle...... wait for scream.... pull handle immediatly.

This of course assumes your not easily distracted and might walk away to chat with the neighbor or have a few beers.

As far as the little sign, thats Keystones CYA. All the black tank flush does is spray water into the tank. Figure out by timing your fresh water tank. If it takes 10 minutes to fill... same hose same pressure through the spray head will take more time to fill the black tank.

Say take no more then one third of this time to be safe, have a watcher posted inside and rinse away.

[Montana_2825]

Thanks for the insight guys. I think the timing idea is a good one.
I plan to have the valve shut. How else can you fill the tank??
On the old RV I used a Hydroflush unit and backfilled the tank at the dump valve, but never was sure how full the tank got. I just ran water in for two minutes and then drained. Repeated that process several times until the drain water was almost clear.

wingnut

[CountryGuy]

You can always fill the toilet by flushing 20 or 30 toilet fulls of water. Fill toilet, flush, fill toilet, flush, fill toilet, etc, you get the idea. When toilet talks back to you (it is full), go outside and pull the black water tank valve.

We have to do this when at Michigan state parks, there is no real good way to use the black flush utlility. Had to do this for years with prior TT, never had a backed up toilet either in 14 years of use.

Carol

[Glenn and Lorraine]

I always flush the black tank after dumping.
I always close the black tank valve while flushing.
I always open the black tank valve before overflowing.
I always use Clear Sewer Adapters while dumping.
I will fill and dump at least 3 times or until the water in the clear adapter is nearly as clear as the water going in.

If I have good water pressure I keep the valve closed 10 to 15 minutes.
With lower pressure I allow additional time.
Only once was I distracted and overflowed. Luckily it was the last flush and it was mostly clear water making for a whole lot easier clean up.

[Chester]

Our 2750 didn't have the outside flush so I used to give my better half the hose and have her hold it in the toilet. I timed the fill from empty to be about 3 mins. Tanks on the 2750 were the same size as all other Montys.

Like Glenn, I flushed the black tank 2-3 times after emptying. I have the clear sewer elbo and just watch that until it's running clear water.

[sreigle]

I think that warning is a liability thing in case you overflow the toilet. My opinion, but that's what I think anyhow. I run ours awhile with the valve open, then close it awhile, open it to let it flush out, close it again, etc., etc. My guideline was to count off the seconds until I got nervous that it might be getting full, then pull the valve. I only went to 150 seconds but someone else here reported they go several minutes without overflowing. I have now managed to forget how many minutes. One of these days I'll ask Vicki to watch and tell me when she can see the water through the toilet so I'll have a feel for how long it takes to fill it. Water pressure will make a difference, too.

[Montana_657]

Steve, the "time to fill" changes depending on the condition of your tank. It stands to reason that if you have a foot of solids built up on the bottom the tank will fill faster then if it's clean. Hopefully, you never get into that situation, but the point is if you have a lot of build up because you have been unable to use the flush the tank will fill faster.

[Glenn and Lorraine]

When the tanks is empty and you first turn on the flush you can hear, at least I can, the water spraying in the tank. as the tank fills the sound becomes muffled to the point that you can barely hear it. At this point I flush for about another 2 minutes and than dump. As I said previously I will do this at least 3 times or until the water coming out is clear.

BTW- In my estimation, the water coming out of the black tank is now clearer/cleaner than either of the gray water tanks.

[Merv]

an easy way to do the tank flush and not overfill is to run a hose into the bathroom and stick it down into the toilet. this way you can see when it is full by looking into the toilet. have a spray nozle on the hose so you can stop the flow when it gets full.
then go outside and pull the dump valve.
works for me.
Merv

[Karl]

One of the reasons for having something open when refilling the black tank using the outside flush is the pressure that will build up in the tank as the water displaces the air. This "could" cause a problem, but it is easy to use something to prop the toilet flush open just a bit to relieve the pressure.

[Parrothead]

There is a little gizmo (I promise never again to use thingy) that we got at CW that holds the toilet flush open. Plastic tube gizmo about 4 inches long and the diameter of the toilet flush opening. It works really well to get more water in the black tank before flushing and I assume would release the air.

[Glenn and Lorraine]

The tank is vented through the roof so air pressure build up is not an issue.

[Montana_657]

Yeah.. after all the trouble to get a outside flush... why would you hold the toilet open to vent the gas into the coach and fool with dirty hoses. The need to do that is what this system is supposed to prevent.

[patodonn]

Glenn and Lorraine have it almost exactly the same as we use. I did time it (empty to full) using the flush system. The time is variable, to a degree, at about 12-15 min, depending on water pressure. The valve is, of course, closed while flushing. I usually stop it at ten min. You can also hear a definite change in the noise of the spray when it gets about 3/4 full.

There is really little to be gained by going all tghe way to "full". As Steve said, it is only a spray nozzle.

You can also fill the black tank with the dump valve open if you have a hose adapter at the outlet connection. The gate valve we installed there has one as part of the assembly. I don't use it because it seems very slow, and all it does is put water into dump manifold, and, from there into whatgever tank has an open dump valve. If you want an alternative method for rinsing out the grey or galley tanks, that is one possibility, but, then again, there is the possibility of overflow....I don't use it for that.

Best,

[campbud]

We were told to always open the black tank valve when flushing or else water would be coming out of the toliet.

[HamRad]

campbud,
Water will NOT come out of the toilet with the valve closed. Or at least it doesn't on mine. I often will do as patodonn and others and close the black tank valve and fill it almost full. Then dump. I often will do this a couple of times to make sure I've gotten everything out of the tank.

But you MUST stay right by the rig where the water is going in. You want to be able to pull the black tank lever at a moments notice. Ask what happens if you FORGET or get BUSY doing something else! As you can imagine.... it is not a pretty picture.

Good luck. HamRad