Help... Again...

[Sandals 123]

Hello all, thanks in advance for your help and patience again with us as we discover the ins and outs of RV life.

We are at our first campsite with full service and I have a couple of questions about Grey and black tanks.

On my 29RKS, we have a drain for the black tank at the front of the unit and a drain for the grey at the back of the unit. From what I have read, the common practice seems to be to drain the black tank and then use the grey tank to clean out the hoses.

Questions:

1. There is a "tank flush" water hose fitting in my control panel. Is this a way to flush out the black tank?

2. If I run my sewer hose from black tank to drain at my site, do I leave the shut off valve open or closed while camping?

Thanks for your help on this stinky topic.

[Canonman]

Your tank flush is for rinsing the black tank. I use the tank flush to fill the black tank prior to dumping (think about how your toilet bowl works). Then fill the black tank at least once more to rinse it out really good. Finally a few gallons to travel with so things don't get a chance to solidify:)
Always leave the black tank closed until you are ready to empty. Use LOTS of water. The more the better if you have it.

[busterbrown]

As Brian mentioned above, always ALWAYS leave your black tank valve closed when hooked up to a sewer connection. Otherwise you'll be playing with the "poo pyramid" problem. We, too, run a separate "black use only" water hose to the black tank flush/rinse prior to opening the valve. Water is your best friend in getting a tank clean.

When at a full hookup campground, we keep the gray tank valve open until the night before departure. THen we close it and fill it as much as possible with our night time showers. By morning, we usually have a semi-full gray tank that will clean the sewer hose after the black tank is emptied. Draining the gray tank is the last step in the process.

[MarkEHansen]

I think I have less experience than the others, but I have a couple comments. I was told never to use the tank flush hose while the black tank valve is closed, as a minor distraction could result in a back-flow out of the toilet into the floor of the trailer.

Whether you leave your gray tank valve open while at the campsite is up to you, but I would plan it such that each time you need to dump the black tank, you have a full (or nearly full, as much as possible) grey tank to provide a lot of water pressure to chase "stuff" out of the dump hose after dumping the black tank.

You can dump the black tank and then use the black tank flush system after, but to me this is more to rinse the interior of the tank, and not to clear the dump hose. I think you need a lot of non-black water to really "flush" the dump hose after dumping the black tank.

Do what's easiest for you, as long as it works :)

[busterbrown]

I think I have less experience than the others, but I have a couple comments. I was told never to use the tank flush hose while the black tank valve is closed, as a minor distraction could result in a back-flow out of the toilet into the floor of the trailer.

Most likely, the "poo-ey" water would travel in the path of least resistance and spill out of the roof vent first while the toilet valve is closed. (<--------albeit, an equally miserable task of cleanup).

After several fill ups using the black tank rinse, most owners will know how long it takes. I am usually doing something near the gate valves during this process and pull the valve after about 5-7 minutes. My toilet bowl is directly over the black tank so I have the 'privilege' of watching the tank fill with my foot on the toilet bowl pedal.

[Canonman]

Mark is correct in pointing out that when cleaning/dumping/rinsing the black tank with the tank flush Pay Attention. This is considered "hazardous waste". If you don't pay attention you will pay the consequences. Yes, I do use the tank flush with the valve closed. No, I have not had any issues with water coming up the toilet (there's a watertight seal). Just keep your wits about you and understand this is a job that needs to be done correctly and efficiently and you'll be just fine.

[Logan X]

As stated above, whatever you do, do not leave the black tank valve open while you are camping. If you do, all of the liquid will drain out and the solids will remain and become the afore mentioned “poo pyramid.” It is very difficult to correct that mistake. Keep the black tank valve closed until you are ready to dump and the fuller the tank is when you dump, the better it drains out.

I leave the valve closed when I use the black tank flush. I use a timer to let me know when the tank is close to full. My toilet is above the tank so I can see it filling up.

[chuckster57]

Leaving the gray tank open can cause food particles to gather and cause odor issues. I dump my gray every night before staying in.

[Gegrad]

I keep all my tanks close then drain the gray tanks as needed. Then I save some gray for flushing after rinsing black tank. We don't typically camp for more than 3-4 nights max at this point, so we can go the whole run with our black without dumping. But I almost never #2 in the trailer because mine always seems to plug up no matter how much water I run through it.

[Sandals 123]

Thanks everyone for the help! Turns out that I have 2 grey tanks. One shares the drain with my black tank from the bathroom and another is for the kitchen.

I tried to hook up the water hose to the Black tank rinse connection and it seemed like there was resistance and water just leaked from the fitting. Am I missing something? I tried it with the black valve open and closed.

[Logan X]

Thanks everyone for the help! Turns out that I have 2 grey tanks. One shares the drain with my black tank from the bathroom and another is for the kitchen.

I tried to hook up the water hose to the Black tank rinse connection and it seemed like there was resistance and water just leaked from the fitting. Am I missing something? I tried it with the black valve open and closed.

The problem with the black tank flush could be the anti siphon valve was installed backwards. On my trailer, I followed the plumbing from the outside of the trailer to under the bathroom sink. Under the sink, the pex pipe and anti siphon valve are visible and accessible. The anti siphon valve on my trailer is connected with compression fittings that can be unscrewed by hand. There are arrows which show which direction water is supposed to flow. This is the first thing I would check, I hope it helps!

[chuckster57]

If your running the black tank rinser and nothing is coming out of the tank drain, odds are the anti siphon valve was installed backwards. VERY common from the factory. Now you just have to find it. It may be under the sink in the bathroom or behind the shower wall. If its behind the shower wall you will need to remove the faucet assembly to gain access to it.

[Canonman]

There is some back pressure (resistance) since you are forcing water through a sprayer with a rather small outlet. I notice some dripping from the hose connection and if I'm not connected just right even spraying.
You should hear water spraying into the tank. You might need to have someone listen from the bathroom or even open the toilet seal to be sure water is running into the tank. If no water is spraying into the tank you might have a problem with the backflow preventer. They have been known to be installed backwards:(

[PARAPTOR]

Sandals.... if this black tank flush has never worked for you may want to check and make sure the anti siphon valve, which is usually located under bathroom sink, is installed in the correct direction.

Update: looks like many of us responding at the same time. I must be the slowest typest (pecker).

[sourdough]

Have to go with the suggestions above. Maiden voyage on this trailer (read "maiden voyage, not PDI) I hooked up the black tank flush to use it. Received a shower from the blow back in 30 degree weather and 30mph winds. Took back to dealership (10 miles away from campground) and anti siphon valve was backward. Shame on me. On the PDI I asked if it had been checked and was told yes - did not insist that I actually saw it work - won't happen again.

[fable081]

Sandals - There has been a lot of great advice here.
1. If you discover it is not the anti siphon valve, I have the same unit as you and had a similar problem except it was the connection from the tank flush to the tank that was not connected. There was no sound coming from the tank yet the underbelly was filling with water that started to drain at the low point drain valves just push up on the belly to see if there is water moving. Dealer had to cut open the belly and repair.
2. Like you I have the gray water tank at the rear that is only used for the kitchen sink. Instead of dedicating another "sewer" hose I added the cap adapters that accept a 3/4 inch hose which I send to my Y coupling that has the same adapter. Sewer remains closed until it requires emptying and the sink continuously drains down the smooth interior with no "stink".

[Frank G]

Make your life simple and safe. Install one of these valves on each of your outlets. Now you can disconnect or connect without any spillage.

Part two, many people with two outlets connect each to a Y fitting and then run a line to the CG sewer. Dump Black, dump each gray close valves and disconnect.

https://www.amazon.com/Valterra-T58-Twist-On-Waste-Valve/dp/B000BGHYJS/ref=sr_1_9?crid=SRTTBGULU2ZQ&keywords=rv+tank+valve&qid=1556654960&s=gateway&sprefix=RV+tank%2Caps%2C153&sr=8-9

[travelin texans]

Agree 100%!!! NEVER EVER leave the black valve open & NEVER EVER use your drinking water hose to rinse the black tank, use a dedicated hose.
My 5er had 1 black & 2 greys, 1 grey for only the kitchen sink/dishwasher & the other was for bath lavatory, shower & wash machine, this valve stayed open when connected to sewer or it would've needed dumped a couple times a day. I closed the bath grey valve a couple days prior to dumping black then opened it last as it's mostly soapy water.

[ncstan]

Your tank flush is for rinsing the black tank. I use the tank flush to fill the black tank prior to dumping (think about how your toilet bowl works). Then fill the black tank at least once more to rinse it out really good. Finally a few gallons to travel with so things don't get a chance to solidify:)
Always leave the black tank closed until you are ready to empty. Use LOTS of water. The more the better if you have it.

Not sure leaving the blank tank closed while doing a black tank flush is the correct procedure, my manual says to leave the black tank valve open while doing the flush. I suspect it maybe be because the water pressure from the flush might build to much pressure in the black tank and cause it to blow out through the toilet end which I'm sure nobody would want.

Just my thoughts, I open blk valve first/drain.. then open gray valve/drain.. close gray valve... then hook up the blk tank flush an and start. You'll see when the water gets clear after running the fluch for a min. or so. Close blk valve and done.

[Logan X]

Not sure leaving the blank tank closed while doing a black tank flush is the correct procedure, my manual says to leave the black tank valve open while doing the flush. I suspect it maybe be because the water pressure from the flush might build to much pressure in the black tank and cause it to blow out through the toilet end which I'm sure nobody would want.

Just my thoughts, I open blk valve first/drain.. then open gray valve/drain.. close gray valve... then hook up the blk tank flush an and start. You'll see when the water gets clear after running the fluch for a min. or so. Close blk valve and done.

This guy has done a lot of black tank cleaning tests. I found this video to be very informative. He shows the difference between leaving the valve open and leaving it closed. The link is below.

https://youtu.be/dfTd0Slt_cU

[Roscommon48]

first off, DON'T use your regualar water hose to flush! you can always get black water back into the hose!


as for flushing to rinse the black tank, i've been rving for years and never yet flushed out the black tank.

You need to learn how long you can NOT dump the black water and then flush it when nearly full to get the full force of drainage.

[sonofcy]

I think I have less experience than the others, but I have a couple comments. I was told never to use the tank flush hose while the black tank valve is closed, as a minor distraction could result in a back-flow out of the toilet into the floor of the trailer.

Whether you leave your gray tank valve open while at the campsite is up to you, but I would plan it such that each time you need to dump the black tank, you have a full (or nearly full, as much as possible) grey tank to provide a lot of water pressure to chase "stuff" out of the dump hose after dumping the black tank.

You can dump the black tank and then use the black tank flush system after, but to me this is more to rinse the interior of the tank, and not to clear the dump hose. I think you need a lot of non-black water to really "flush" the dump hose after dumping the black tank.

Do what's easiest for you, as long as it works :)

I added a water timer to my black flush because I am very forgetful. I already overflowed the bathroom sink twice!

[LHaven]

If your sink is connected to the black tank, you have unresolved problems. :eek:

[sonofcy]

If your sink is connected to the black tank, you have unresolved problems. :eek:

Not connected, I was running the sink to fill the grey in order to flush the sewer hose.

[efrulla]

I own a Cougar 25RES and both greys and the black dump through the same outlet. Once the black is dumped I use the tank flush liberally. I also purchased a 90 degree clear elbow which contains a hose connection and a built in one-way valve. Once the flush is complete, I close all of the gate valves, hook my grey hose to the 90 degree outlet and turn the water on. This gives my sewer hose a flush with clean water after it was flushed with the grey water. If you do this be real anal about making sure all of the gate valves are closed. Forget to do that and the mess will make sure you do not forget again.

[terrythetech]

Just a side note with all the good replies. When we are going to be at a campsite with hookups, and after i dump my tanks and close the valves, I always step on the toilet flush for 2 full minutes after adding my "Happy Camper" chems. You dont always know who may use the rest room and it allows for a bit of comfort knowing a pyramid doesnt start from the get-go.

[JRTJH]

Just a side note with all the good replies. When we are going to be at a campsite with hookups, and after i dump my tanks and close the valves, I always step on the toilet flush for 2 full minutes after adding my "Happy Camper" chems. You dont always know who may use the rest room and it allows for a bit of comfort knowing a pyramid doesnt start from the get-go.

I do essentially the same as you, but a slightly different technique. Here's how I do it and why: Both Dometic and Thetford toilets have a "2 step valve" that allows for filling the bowl when the valve is slightly depressed, without opening the ball/flush hole cover. I step on the toilet flush valve and fill the bowl completely, to just under the water ports. My toilet bowl (Dometic 310) holds approximately 2 gallons of water. Then I flush and fill it again. That puts 4 gallons of water in the black tank (plus what wasn't dumped).

Now, the why: Water pressure is very inconsistent from campground to campground and even more so when using the onboard water pump. So, using the "timed method" at one campground may give you 8 gallons in the black tank and another campground may only give you 2 gallons, depending on flow rates and pressure. Additionally, holding that "big, odorous" hole open will allow the smells to flow up, especially if there's a roof vent open. That fills the bathroom (and maybe the trailer) with smells that most of us don't want to endure. So, to get closer to a "known water quantity" and "prevent unwanted odors", try my method, you'll get 4 gallons every time and hopefully not "fill the trailer with aroma".....

[LHaven]

Additionally, holding that "big, odorous" hole open will allow the smells to flow up, especially if there's a roof vent open.

I used to do the toilet fill trick on my old rig, but on my new Cougar, the hose flush attachment has spoiled me -- I just blow an extra 20 seconds of water in after closing the valve for the last time, and call it a wash [pun intended].

[MattE303]

I do essentially the same as you, but a slightly different technique. Here's how I do it and why: Both Dometic and Thetford toilets have a "2 step valve" that allows for filling the bowl when the valve is slightly depressed, without opening the ball/flush hole cover. I step on the toilet flush valve and fill the bowl completely, to just under the water ports. My toilet bowl (Dometic 310) holds approximately 2 gallons of water. Then I flush and fill it again. That puts 4 gallons of water in the black tank (plus what wasn't dumped).

Now, the why: Water pressure is very inconsistent from campground to campground and even more so when using the onboard water pump. So, using the "timed method" at one campground may give you 8 gallons in the black tank and another campground may only give you 2 gallons, depending on flow rates and pressure. Additionally, holding that "big, odorous" hole open will allow the smells to flow up, especially if there's a roof vent open. That fills the bathroom (and maybe the trailer) with smells that most of us don't want to endure. So, to get closer to a "known water quantity" and "prevent unwanted odors", try my method, you'll get 4 gallons every time and hopefully not "fill the trailer with aroma".....Due to my obsessive need to measure things :o, I use a gallon milk jug to measure the water. With the toilet valve closed, I drop a couple of the Camco Orange TST drop-ins into the bowl, pour some water from the jug over them and wait to make sure the packets dissolve, then pour in the rest of the water and open the flush valve.

[JRTJH]

Due to my obsessive need to measure things :o, I use a gallon milk jug to measure the water. With the toilet valve closed, I drop a couple of the Camco Orange TST drop-ins into the bowl, pour some water from the jug over them and wait to make sure the packets dissolve, then pour in the rest of the water and open the flush valve.

There have been many reports of the plastic "envelopes" that contain the TST liquid not completely dissolving. They are reported to "partially dissolve, release the liquid, giving the appearance of completely dissolving" when actually, they "burst/leak" the liquid and remain undissolved. That plastic, similar to saran wrap or plastic film, can hang up in the slide valves, cause them to leak and create problems in the future.

If you have an "obsessive need" to measure, you might want to add a step and cut those packets open, dump the contents into one of the jugs of water and toss the plastic in the trash.

[MattE303]

There have been many reports of the plastic "envelopes" that contain the TST liquid not completely dissolving. They are reported to "partially dissolve, release the liquid, giving the appearance of completely dissolving" when actually, they "burst/leak" the liquid and remain undissolved. That plastic, similar to saran wrap or plastic film, can hang up in the slide valves, cause them to leak and create problems in the future.

If you have an "obsessive need" to measure, you might want to add a step and cut those packets open, dump the contents into one of the jugs of water and toss the plastic in the trash.The TST packets I use contain a powder rather than a liquid, but the plastic "wrapper" is just as you describe (like saran wrap), so I could easily see it causing issues if it didn't dissolve completely. I will try cutting them open and pouring the powder in by hand, thanks for the tip John! (tx)

[JRTJH]

You're welcome. Hopefully it will help you avoid any issues with leaking dump valves. A couple years ago we had a report from someone stating that their black tank valve was "fouled" by the packets and they had to replace the valve to get it to stop leaking. Many other's have reported that the packets don't dissolve or only partially dissolve. If cutting them open and tossing the plastic keeps you "on top of the black tank" rather than "under it for repairs" then it's a "win-win" situation !!!!!

[MattE303]

You're welcome. Hopefully it will help you avoid any issues with leaking dump valves. A couple years ago we had a report from someone stating that their black tank valve was "fouled" by the packets and they had to replace the valve to get it to stop leaking. Many other's have reported that the packets don't dissolve or only partially dissolve. If cutting them open and tossing the plastic keeps you "on top of the black tank" rather than "under it for repairs" then it's a "win-win" situation !!!!!for sure, having to service or replace the black tank valve is the last thing I want to mess with (yikes)!!

[chuckster57]

TST citrus comes in liquid form. I was gifted a tub of Dometic blue packets, used two one weekend to test and found after 3 days the intact packets came out with a rinse. No packets allowed here!!

[MattE303]

TST citrus comes in liquid form. I was gifted a tub of Dometic blue packets, used two one weekend to test and found after 3 days the intact packets came out with a rinse. No packets allowed here!!I just looked that up on Amazon a few minutes ago! I think I'll cut open the remaining packets I have (as John suggested), and try the liquid form when I run out of packets, thanks again guys!

[JRTJH]

I buy the TST liquid orange at WalMart. A 32 ounce size for around $11 lasts all season. No plastic pouches to worry about and it fits under the vanity with the bleach, spray wax, Aerospace 303 and extra rolls of TP/wet wipes.

[sourdough]

I have to 2nd what chuckster said. Tried the packets one time; went to dump and right thru my clear elbow came the intact packet - they found their way to the dumpster that day.

[MattE303]

This guy has done a lot of black tank cleaning tests. I found this video to be very informative. He shows the difference between leaving the valve open and leaving it closed. The link is below.

https://youtu.be/dfTd0Slt_cU

great video, definitely worth a look for anyone who has an rv with a black tank, although I think he does a bit of a disservice to the Sewer Solutions device; for me the real value of the SS is its ability to take the place of a macerator in at least some situations. Using the SS, I dump into a sewer cleanout at my house that is about 70-80' away from where I park the toy hauler, using 3/4" PVC pipe. If you need to go much longer distances, or pump uphill, you'll probably need a macerator... if not, the SS is a much cheaper but still very effective solution.

[jimborokz]

great video, definitely worth a look for anyone who has an rv with a black tank, although I think he does a bit of a disservice to the Sewer Solutions device; for me the real value of the SS is its ability to take the place of a macerator in at least some situations. Using the SS, I dump into a sewer cleanout at my house that is about 70-80' away from where I park the toy hauler, using 3/4" PVC pipe. If you need to go much longer distances, or pump uphill, you'll probably need a macerator... if not, the SS is a much cheaper but still very effective solution.
I use the SS at my long term winter site because I run into a 2" pipe that runs 200' down a low slope to the septic tank and it works well. I don't use it for rincing as I have the Tornado flush which I run for about 10 minutes then shut the valve for about 2 min. I repeat this procedure a couple times and call it a day. Then I shut the valve and slowly walk back to the shut off for the flush and by then there is some water in the tank.

As for packets, I used them in my previous rig with leaking valve ussue so now I just alternate with Happy Camper one tank and then the Eco method the next. This seems to work well and keeps the sensors working pretty good.

[notanlines]

Ever so slightly off topic, but DW used Tide Pods for our laundry when first on the market for a short period. The plastic-like covering would not dissolve properly and ruined a number of t-shirts and a few bed sheets as I remember. Tide laid no claim to responsibility and we immediately switched to another brand and a liquid. Not a fat chance any wrapped 'pods' are going in any of our tanks!

[{tpc}]

Interesting read about the packets. I haven't experienced an issue with mine, though once in a time of need I did happen to open a couple packets and dump them in, though I'm fairly certain I tossed the package in after it.

I don't recall the exact brand off hand, but I have also experienced a couple of semi open packets on occasion, maybe the ones I have are thinner or something.

[Tooth Ferry]

I tried a different way to refill black tank to clean it this trip. I took a plastic drinking cup (soft) and cut the bottom out of it and flushed the toilet and placed the cup in the opening and let the water fill up in the bowl and run into the tank. No extra pressure and the easy ability to see when the tank was full and simply remove the cup and let the flush valve shut off. I did this twice and it was much more simple than fussing with the hoses and valves. The soft cup did not damage the seal as the seal still functioned well . Also could get (volunteer) to watch it and shut it off while I was doing other chores.