Black water tank.

[Sprky]

Just bought my 5th wheel.3950BR Was wondering how to fill black water tank without sticking a hose down the toilet. The sensor says it’s full even when empty I figured I would fill it halfway for our trip this week and let it slosh around while traveling. There is what looks like a valve in the hook up area. I will get a pic when it gets light outside.

[Lee-CI]

Year and model would be very helpful for accurate advise. If it is a late model unit, there should be a black tank rinse port in your convenience center to attach a water hose to. Once water is added you might consider adding a quarter cup of Dawn dish soap to the tank as well. Good luck as the tank sensors are notoriously inaccurate.

[DutchmenSport]

You can put an RV flush valve prop into the hole of the toilet, which will hold the bottom of the toilet (slide) open and allow water to run without having to hold your foot on the peddle. When the water reaches the bottom of the neck of the toilet, then pull the prop out of the hole and flush out the tank.

Before the days of black tank flushers, this is how I filled my black tank. It works, easy, and no mess.

[Daryles]

Use a water meter so you don't over fill it.
I use this all the time when filling our freshwater tank (42 gallons is the average for our freshwater tank).

[Sprky]

2017 3950br

[RMcNeal]

As Lee said, you could use the black tank rinse port to fill your tank. I do that often to clean it, then put about 7 gallons in to start the next cycle. I use a water meter like the one pictured above to fill fresh water and to fill/flush the black tank. No guessing that way and I don't overfill the black tank.
If the black tank is very dirty, you might try using a chemical like Unique Tank Cleaner to let it sit overnight and get the tank clean. The sensors won't likely work for long, but at least you'll know there is not a pyramid forming to block the tank up.

[KingRanchFan]

Using that water meter idea, several years back I added one of those inline to my fresh tank so I could monitor more accurately the water coming out. The meter works both ways. I get about 54 gallons in from bone dry, but you seem to get in the 40's coming out before the pump starts sucking air. So it's very interesting to watch who uses more taking a shower, LOL. It sure helps knowing where your at boondocking. It's not a perfect solution but it's better than three lights on our systems. You reset the meter when full and it will count back up as you pull water from tank.

[High5er]

It's definitely a good idea to regularly flush out your black tank, but I wouldn't get your hopes up too high on the sensors reading properly. In every RV we've had, I've been able to get them to stop reading full, but it's always temporary. As an example, I recently did a flush and it showed completely empty. I added 5 gallons of water and chemical and it went back to showing full. I think it's a conspiracy by RV manufacturers to give us something to obsess about

[tom woodward]

Mine and most gauges stop working shortly after the warranty runs out. I’ve come to learn that you can hear the toilet getting full via the Doppler effect if you listen carefully. When the shower does t drain or drains slowly the grey tank is full. I have a black tank spray arm but it does t seem to clean the sensors. We always put the proper chemicals in after dumping, add a couple of gallons of water and slosh it around going down the road. Still the sensors haven’t worked in the black tank for at least the last four years and I don’t miss them.

[mgmillsa]

Just remember whatever you do to make sure it's idiot proof (or Army proof as we would say in the Air Force ). Never turn on flow to the flush port without opening the drain. The flow meter is a great option, but be conservative on the amount and set a second alarm. My buddy overflowed his Airstream black water because he got distracted while filling via flush port. That's a tough mistake to overcome!

[Ttman]

Originally Posted by KingRanchFan

Attachment 16572Using that water meter idea, several years back I added one of those inline to my fresh tank so I could monitor more accurately the water coming out. The meter works both ways. I get about 54 gallons in from bone dry, but you seem to get in the 40's coming out before the pump starts sucking air. So it's very interesting to watch who uses more taking a shower, LOL. It sure helps knowing where your at boondocking. It's not a perfect solution but it's better than three lights on our systems. You reset the meter when full and it will count back up as you pull water from tank.

I love that idea, I’m stealing it, thanks!