Correct way to flush black tank

[Jimmyd]

New to Class C Greyhawk 29MV black tank flushing. Read the Jayco manual but still a little confused. I understand where to connect the flushing hose but do I need to set the manifold valves to flush the black tank?
My previous coaches just had the connection to hookup to turn on the water and then open the drain valve.
Please clarify the proper procedures for flushing. Thank you, Jimmyd

[Camper_bob]

You don't need to change any of the manifold valves; the black flush runs directly from that connection on the side of the coach to a nozzle in the side of the black tank.

Here's what I do:

1) Make sure the tank is at least 2/3 full before dumping. Add fresh water if necessary
2) Dump the black tank
3) Using a dedicated hose, NOT your drinking water hose, run the flush for a few minutes with the black valve open
4) Close the black valve (yes, I know the manual says don't do that) for about 2 minutes (depending on size of tank of course) while the flush fills the black tank some. DO NOT GET DISTRACTED during this step!! If you overfill your black tank with the flush, it will come up through the toilet! SO PAY ATTENTION! You're not trying to fill the black tank all the way up again, you're just trying to get some water in there for another good gravity flush to get all the "heavy bits" off the bottom of the tank.
5) Dump the black tank again
6) Repeat steps 3-5 two or three times to get as much "stuff" out of the tank as possible
7) Turn off the flush, close the black valve, dump gray tank.
8) Put 3-5 gallons in the black tank through the toilet with tank chems

Notice, nowhere in this process did I change the manifold. By design, the waste tanks and assorted plumbing are completely separate from the rest of the water system.

Also, don't do this at a dump station where others are waiting for you. I only do this process at home or if I'm at a full-hookup site.

[TWP723]

Originally Posted by Camper_bob

You don't need to change any of the manifold valves; the black flush runs directly from that connection on the side of the coach to a nozzle in the side of the black tank.

Here's what I do:

1) Make sure the tank is at least 2/3 full before dumping. Add fresh water if necessary
2) Dump the black tank
3) Using a dedicated hose, NOT your drinking water hose, run the flush for a few minutes with the black valve open
4) Close the black valve (yes, I know the manual says don't do that) for about 2 minutes (depending on size of tank of course) while the flush fills the black tank some. DO NOT GET DISTRACTED during this step!! If you overfill your black tank with the flush, it will come up through the toilet! SO PAY ATTENTION! You're not trying to fill the black tank all the way up again, you're just trying to get some water in there for another good gravity flush to get all the "heavy bits" off the bottom of the tank.
5) Dump the black tank again
6) Repeat steps 3-5 two or three times to get as much "stuff" out of the tank as possible
7) Turn off the flush, close the black valve, dump gray tank.
8) Put 3-5 gallons in the black tank through the toilet with tank chems

Notice, nowhere in this process did I change the manifold. By design, the waste tanks and assorted plumbing are completely separate from the rest of the water system.

Also, don't do this at a dump station where others are waiting for you. I only do this process at home or if I'm at a full-hookup site.

Exactly how we do it. X2

[Jimmyd]

Thank you both for your quick response. This is exactly what we did on our previous coaches. The manual is a little confusing. Safe travels, Jimmyd

[cabinetmaker]

Jimmy...sounds like your enjoying that new 29MV! We sure like ours.

One other thing about black tank flushing...try and do this immediately after dumping the tank while the paper and any remaining stuff (nice word for it) is still soft enough to flush out.

If it has time to dry on the sensors you will never get correct readings from your display again.

If the park pressure is not too high to damage the lines I will not use a pressure reducer on the dedicated hose for the flush to give it more boost. Be carefull here as I have a pressure gauge on my hookups and some rv parks have very high pressure so I carry a old pressure reducer just for the black flush hose and will use it when pressure is too high (over say 75psi)

[Mustang65]

Correct way to flush black tank is to have the spouse do it! And of course in this case I am the spouse in charge of the tanks. Every Thursday morning (seasonal) my iPhone alarm goes off at 10:30 AM "EMPTY BLACK/GRAY TANKS".
Camper_Bob has it down to a science. I close my Black Tank for 3 minutes with an iPhone alarm while the spinner does its work. I repeat until clear water is seen in the transparent window on the hose adapter.

Don
My Registry

RVing with SOLAR

[Jimmyd]

Thanks Cabinetmaker and Mustang, In our previous Motorcoach’s I would hook up the flushout hose and fill the tank to 90% and open the gate and let ur rip. Then repeat this process a few more times. The Jayco doesn’t have the sensor reading in the wet Bay so I rely on my wife to keep reading the inside gauge. The last time we flushed here in Carrabelle, Fl after I was finished I noticed a little water dripping under the sink in the bathroom. I thought maybe the check valve was not working properly but then in the manual it said to always keep the gate valve open when flushing the black tank? This week we will he heading down to Dunedin, Fl and I will give it another test.
Mustang, looks like you live in Clearwater. We used to live out on the beach. Miss a lot of things but not the traffic. Thank you both for the great info. Jimmyd

[Mustang65]

Originally Posted by Jimmyd

This week we will he heading down to Dunedin, Fl and I will give it another test.
Mustang, looks like you live in Clearwater. We used to live out on the beach. Miss a lot of things but not the traffic. Thank you both for the great info. Jimmyd

I live in Dunedin. Let's see, if you are staying at a CG in Dunedin, the only one I know of is the one on Curlew and Alt 19. Curlew takes you out to Caladesi Island. Love the beach there, the dogs loved the pet beach also. Caladesi can be like Clearwater beach on the weekends. I usually park on the South side of the causeway leading to Caladesi. Yes, Clearwater Beach is a nice place to visit, using Uber, can't go wrong for an $11 ride. Send me a PM when you get here and I will stop by and say HELLO!
Don

My Registry

RVing with SOLAR

[cabinetmaker]

Originally Posted by Camper_bob

You don't need to change any of the manifold valves; the black flush runs directly from that connection on the side of the coach to a nozzle in the side of the black tank.

Here's what I do:

1) Make sure the tank is at least 2/3 full before dumping. Add fresh water if necessary
2) Dump the black tank
3) Using a dedicated hose, NOT your drinking water hose, run the flush for a few minutes with the black valve open
4) Close the black valve (yes, I know the manual says don't do that) for about 2 minutes (depending on size of tank of course) while the flush fills the black tank some. DO NOT GET DISTRACTED during this step!! If you overfill your black tank with the flush, it will come up through the toilet! SO PAY ATTENTION! You're not trying to fill the black tank all the way up again, you're just trying to get some water in there for another good gravity flush to get all the "heavy bits" off the bottom of the tank.
5) Dump the black tank again
6) Repeat steps 3-5 two or three times to get as much "stuff" out of the tank as possible
7) Turn off the flush, close the black valve, dump gray tank.
8) Put 3-5 gallons in the black tank through the toilet with tank chems

Notice, nowhere in this process did I change the manifold. By design, the waste tanks and assorted plumbing are completely separate from the rest of the water system.

Also, don't do this at a dump station where others are waiting for you. I only do this process at home or if I'm at a full-hookup site.

Perfect procedure Camper Bob! This needs to be made a sticky...Ha! be careful don't say that too fast it comes out stinky!!

[Camper_bob]

Yup! I always use a timer too. I actually measured the flow from my faucet at home, so I know exactly how long to let the tank fill. If the water at the CG is roughly the same pressure, I can use that technique there too, but I always give myself a little "wiggle room". I don't ever fill the tank using the flush to more than about 80% I'd say. And then only on the first fill-n-flush. Each iteration after that I do a little less. It's a poop tank, so I'm just trying to get the major stuff out, it's never going to be what I would call "clean", so I just do what I can.

Since I bought a new unit that I changed the toilet out on before the first outing, I actually got to see a CLEAN black tank! I even said "hello clean black tank, this is officially the last time you'll ever be this clean!" Then I bolted down the new toilet and "bombs away"!! LOL!!

[Jimmyd]

Originally Posted by Mustang65

I live in Dunedin. Let's see, if you are staying at a CG in Dunedin, the only one I know of is the one on Curlew and Alt 19. Curlew takes you out to Caladesi Island. Love the beach there, the dogs loved the pet beach also. Caladesi can be like Clearwater beach on the weekends. I usually park on the South side of the causeway leading to Caladesi. Yes, Clearwater Beach is a nice place to visit, using Uber, can't go wrong for an $11 ride. Send me a PM when you get here and I will stop by and say HELLO!
Don

My Registry

RVing with SOLAR

Don, we are staying at the Dunedin RV Resort. Been there many times. The only place in the area. Lived there and boated out of there for 32 years. Not sue yet where the PM is on this forum? Learning my way around. Be down there Monday evening for one week. Jimmyd

[michael.g]

I agree with camper_bob, except I usually fill the black tank for a lot longer than 2 minutes. That usually only puts a few gallons in the tank. I like to get the tank about 2/3 full, then I open the valve again. I usually fill and flush about 3 times if I have the time.

-Michael

[memphis02]

I bought a cheap garden hose totalizer on Amazon. I checked it against a 1gal jug and 5 gal bucket and am confident in its measurement. I love using them to fill my fresh water and when rinsing my black tank.

[cabinetmaker]

Originally Posted by memphis02

I bought a cheap garden hose totalizer on Amazon. I checked it against a 1gal jug and 5 gal bucket and am confident in its measurement. I love using them to fill my fresh water and when rinsing my black tank.

Wow! I like that! Great idea...something else I need. Thanks!

[Jimmyd]

Originally Posted by memphis02

I bought a cheap garden hose totalizer on Amazon. I checked it against a 1gal jug and 5 gal bucket and am confident in its measurement. I love using them to fill my fresh water and when rinsing my black tank.

I like that flow meter. Guess I will add that to my collection. Thanks for the info. Jimmyd

[Camper_bob]

Originally Posted by michael.g

I agree with camper_bob, except I usually fill the black tank for a lot longer than 2 minutes. That usually only puts a few gallons in the tank. I like to get the tank about 2/3 full, then I open the valve again. I usually fill and flush about 3 times if I have the time.

-Michael

My flow is right at 5GPM, less when it has to go through the sprayer in the tank, so I usually set a timer for 5 minutes on a 30+ gallon tank and that usually does the trick.

Originally Posted by memphis02

I bought a cheap garden hose totalizer on Amazon. I checked it against a 1gal jug and 5 gal bucket and am confident in its measurement. I love using them to fill my fresh water and when rinsing my black tank.

I totally didn't know such a gadget existed! Super neat, and not too expensive!

[jloco]

Originally Posted by TWP723

Exactly how we do it. X2

X3
BTW... following these instructions will make your tank meter accurate.

[cabinetmaker]

Jimmy...I forgot to mention that we will put a little Pinesol or Murphy's Oil Soap in the holding tanks after flushing.

We add a few gallons of water and then the Pinesol or Murphy's and hit the road. The sloshing does a great job cleaning the tanks and the pine oil in the Pinesol or Coconut in the Murphy's helps lubricate the seals on all the valves and such.

When we get to our destination we will hookup and dump this solution first...then it's do the normal procedure.

Just something we started doing years ago and noticed our sensors always seem to work!

[Jimmyd]

Originally Posted by cabinetmaker

Jimmy...I forgot to mention that we will put a little Pinesol or Murphy's Oil Soap in the holding tanks after flushing.

We add a few gallons of water and then the Pinesol or Murphy's and hit the road. The sloshing does a great job cleaning the tanks and the pine oil in the Pinesol or Coconut in the Murphy's helps lubricate the seals on all the valves and such.

When we get to our destination we will hookup and dump this solution first...then it's do the normal procedure.

Just something we started doing years ago and noticed our sensors always seem to work!

That’s what we did on our previous coaches. Almost forgot about that. Thanks for the heads up. Safe travels, Jimmyd

[Vergari59]

we do exactly what camper BOB does. I cant stress enough that the ONLY thing on your mind when you are doing step 4 is to NOT walk away from that gate while it is filling back up. You do not want a waterfall of black water running down your roof.