Author Topic: Tank flushing  (Read 3003 times)

Dennis Hackert

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Tank flushing
« on: January 27, 2025, 03:41:40 AM »
question 2 of 100
As you will be able to figure out by my questions, that I have never owned and operated a motor home.
At the least I should give all a good laugh.
Sewer draining process? the book says to flush after every dump (emptying process) . What if you decide to empty at a reststop or truckstop where you have no shore water hook up, how do you rinse flush tanks? Is it wrong to hook up a hose from fresh water tank to rinse gray and black tanks? At present I do not see a place to hook up a hose from fresh on board water, I will have to install a hook up.

BTW , you will find this funny. My first flush from shore water, I had water pouring out above aqua hot system(passenger side) water coming from up on top in behind pantry. I was totally baffled. After reading on this forum found out about the vacuum breaker valve, but it was good, the plastic one way check valve next it was cracked. That was my first experience with this forum, this is so awesome, much gratitude to all you road warrior engineers. Thank You!
DH
2006 PATRIOT 40' WITH CAT C13 (525HP)

Joel Ashley

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Re: Tank flushing
« Reply #1 on: January 27, 2025, 10:09:04 AM »
Keep a separate non-white (to discern it from potable water ones) hose to use just with your built-in flush system.  A backflow attachment may be used at one end as extra protection of source systems.  I stow my yellow hose in a bay separate from the water bay where the white potable hose is stored fastened end to end, hung from a bay ceiling hook. 
https://www.amazon.com/Camco-RhinoFLEX-Black-Water-Clean/dp/B06XGW1NGD/ref=asc_df_B06XGW1NGD?mcid=f924b67af98e3540977d437f852adf5f&tag=hyprod-20&linkCode=df0&hvadid=693447639265&hvpos=&hvnetw=g&hvrand=9259679508358179417&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032835&hvtargid=pla-433879943422&th=1

You don’t necessarily have to flush after every single dump, as at rest stop or govt. dumps with no rinse end fittings, but if time allows it helps keep the factory black tank sensor(s) from clogging failure.  If an aftermarket external level-sensing system replaced the original in-tank one on your ‘06 via a previous owner, then flushing isn’t as critical.  But it can keep grundge from getting hung up in the waste slide valve, and provide a relatively clean stored waste hose. 

Just use a sink faucet and the water pump for gray rinse if in a pinch, and hold the toilet flush open to do the black tank.  It adds a few gallons of clean water, then if no one’s waiting in line behind you, disconnect and drive back and forth 10 feet once to slosh it about before reconnecting for a final valve release.  But that of course doesn’t well-rinse the black tank walls like a built-in San-E-Flush with multiple spray heads.  It can help flow out to raise the curbside slightly with the air level system. 

I don’t know of anyone that reroutes onboard water to connect to a San-T-Flush.  The pressure might not be as effective as residential anyway.

Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Eric Maclean Co-Admin

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Re: Tank flushing
« Reply #2 on: January 27, 2025, 08:46:59 PM »
Dennis
As Joel stated it's not necessary to flush your black tank every time you dump .
But I have some tips to help you negotiate the tanks.
First most people don't use enough water in their toilets as a rule of thumb you should fill the bowl at least half full or above .don't worry about filling the black tank too fast as the grey always fills up first .
Second it's better to have your black tank at least half full before dumping the extra water helps carry the solids away.
Third never leave the black tank dump valve open this allows the liquids to drain away leaving the solids behind creating the dreaded poop pyramid in the tank.
Fourth always dump your black before your grey this way the gray water flushed out the dump hose so its clean/eric to put away.

Now for a trick that will answer your question.
When dumping at a dump station or rest stop dump your black first once it is done running out with the hose still connected lift the hose up about two feet off the ground close to the coach and then with the black valve still open now open the gray valve and allow the grey water to run back into the black tank for several seconds then close the grey water dump and lower the hose back down this allows you to use your grey water to flush the black tank do this two or three times and then finish up by dumping your remaining grey water to flush the hose out before puting it away.

This allows you to keep things clean until you can take your time to do a good flush ( best done with a full hookup) at an RV park.

If you encounter tank order there are several tank additives on the market but over the years Ive  found that this recipe from the clean tank guys works as well as any

https://kleentank.com/tank-solution-recipe/

Hope this helps
Eric
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Steve Huber

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Re: Tank flushing
« Reply #3 on: January 27, 2025, 10:41:10 PM »
Dennis,
While Eric's approach of elevating the dump hose and allowing gray tank water to enter the black tank is OK if you are careful and don't have access to shore water, I would not recommend it for general use. Your coach has a tank flush hookup. Use it each time you dump if possible. Turn it on and close the drain valve as you want to allow sufficient water in the tank to create a venturi action when you open the drain valve to help pull all possible debris out of the tank. I recommend a clear plastic fitting between the tank drain valve and the drain hose. That way you can repeatedly flush the tank until you see clear water coming from the tank. Water is critical to tank odor control. I would always add 2-3 gallons of water to the black tank after dumping. That and a capfull of Tank Tech kept my tanks odor free.
Steve
Steve
Coachless
2015- 6/24  07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp

Eric Maclean Co-Admin

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Re: Tank flushing
« Reply #4 on: January 27, 2025, 10:55:04 PM »
Dennis
When using your tank flush with the black tank valve closed it is important to keep an eye on the tank level too often people have been distracted while doing this and allowed the black tank to over fill giving the water nowhere to go but up the vent stack causing a volcano of --------- on the roof.
As Steve mentioned you need to get at least a 1/4 tank or more to get that velocity of flow to carry away all the TP and other things that tend to stick to the sensors and the sides of the tank.
And as Steve pointed out it's a good idea to start your tank with several gallons of water so that the incoming solids from the toilet don't impact a dry tank bottom which allows then to stick .

Hope this helps
Eric
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Dennis Hackert

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Re: Tank flushing
« Reply #5 on: January 28, 2025, 01:25:41 AM »
Wow, you guys are great, thank you for all the advice here, it is evident that there is a certain amount of science involved.
This is weird, but I cant wait to get my tanks full of s--- so I can try these ideas. :)
Basically bottom line you want to use and keep enough water in black to carry solids out when dumping.
  Let me ask a simple question, should I switch to these other new tech devices for keeping track of tank levels and accept the fact that the internal sensors are old technology and I should invest in the new? or is the new also problematic? I know there is maintenance with all but I do want to reduce maintenance.
Thank you for sharing and taking time
DH
2006 PATRIOT 40' WITH CAT C13 (525HP)

Eric Maclean Co-Admin

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Re: Tank flushing
« Reply #6 on: January 28, 2025, 03:30:42 AM »
Dennis
At 26 years of age one of the indicator lights on my original panel died so it would show 1/2 and skip the 3/4 and go directly to full which is not ideal as you really don't get a warning before the tank is full and of course it uses the same set of indicator lights for fresh,gray and black tanks with the same results.
But until the panel developed problems the system worked not bad at least most of the time anyway.

So to deal with the panel failure I change my system out to the Sealevel system which uses external tank sensors stuck on the out side of each tank and uses the existing wiring to a new panel which also has Bluetooth connectivity to your android phone or tablet.
To be honest no matter what system you have whether they have internal or external sensor toilet paper stuck on the side of the tank or sensor can foul the creating false readings however I think the external sensors I have now tend to work somewhat better the key to keeping those sensors working well is tank flushing keep the tanks well flushed and they work pretty well.
If you're going to  change out your system I highly recommend the sea level system .

https://www.rvupgradestore.com/Garnet-709-BTP3-Seelevel-II-Tank-Monitoring-System-p/709-btp3-1003.htm?gclid=CjwKCAiA-ty8BhA_EiwAkyoa3-p-mbwX1Wusk5PgHVqhUaUOXqHFi7qKRU7wMbsWBb_ntoJxoNtblxoCLO0QAvD_BwE&gad_source=1


Hope this helps
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Dennis Hackert

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shocks, front steering
« Reply #7 on: January 28, 2025, 01:10:08 PM »
Thank You , That does help, and also for the link to a new system, I may try my existing for now, probably upgrade down the road, mainly because of bigger fish to catch.
Like, I want to get my front end looked at for shocks, looseness and alignment.
Wonder If anyone has a reference of a service shop around Nashville TN, preferably on north side?
And Bilstein verses Koni ? the rear have been changed but I need to replace fronts (believe there is four)I have been doing a little reading and searching but still not sure, am leaning toward Bilstein as someone said they think they have a special valve designed specifically for RV's?
Thank you Eric
2006 PATRIOT 40' WITH CAT C13 (525HP)

David Ciotti

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Re: Tank flushing
« Reply #8 on: January 29, 2025, 11:57:27 AM »
When I am getting ready to go on the road I will drain both grey and black tanks then buy a big bag of ice and dump it into the toilet.  The ice, while driving, will slosh around and remove the mess pyramid if there is one in the black tank.
2002 Marquis Jasper. 40'. Cat C12

Joel Ashley

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Re: Tank flushing
« Reply #9 on: January 30, 2025, 03:18:08 AM »
Dennis, I’m a vote for Koni’s, as you’ll find many are here.

But a point of Forum procedure should be noted:  preferences here are for broaching different question categories in their own new posts.  Changing a reply (“Re:”) title doesn’t alter that.  And you are more likely to get responses to individual topic threads that way than from stacking multiple questions on very different coach subjects all in one new thread, or from adding them in subsequent replies. 😉

Joel

Addendum:  I read this thread before others newly posted, and later saw your newer one.  So I’m glad you picked up on the “etiquette” yourself, and obviously got my inference even before I jumped in.  We appreciate your astute awareness, and look forward to helping you sort through your new-to-you coach head scratchers.
« Last Edit: January 30, 2025, 03:29:21 AM by Joel Ashley »
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat
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