Those with two black tanks

[CajunAsian]

Does the blank tank flush, flush both the front and rear black holding tanks?

Thanks in advance

[Getn off]

Not in my Cyclone. I have a black and a grey handle forward that drains forward grey and forward black. I also have a grey and black handle aft that drains the aft grey (through the forward lines btw!) and an aft black that drains the aft black tank.
Not sure on ur specific model of course.
Troy

[JRTJH]

Originally Posted by CajunAsian

Does the blank tank flush, flush both the front and rear black holding tanks?

Thanks in advance

From a "procedural perspective" many/most can't logically flush both tanks from one port (without a selector valve to isolate tanks)...

Most trailers with two black tanks have two sewer connections, a front and a rear connection. It's difficult, at any dump station to connect both outlets at the same time, and, if only one is connected and "both fill with flushing" then you could readily overfill/damage one tank while flushing the other.

So, for that reason, few trailers have a "dual tank flush capability" and those that do will have a selector valve that only permits flushing one tank at a time. On those, imagine the potential for damage "IF" the owner thinks he has selected the front tank and is waiting patiently for the tank to rinse, but has accidentally selected the aft tank and it has "overfilled, flooded the bathroom and burst the tank while he's "carefully watching the front outlet for water to start flowing out of the tank......

Yep, it happens, probably more than you'd imagine.....

[chuckster57]

When I worked at a dealership that sold Grand Designs, the models with 2 black tanks had 2 separate rinser connections.

[Essvar]

Originally Posted by chuckster57

When I worked at a dealership that sold Grand Designs, the models with 2 black tanks had 2 separate rinser connections.

This is the answer, if you have two tank flush connections then yes. If you only have one tank flush point then it will only flush the main tank.



My Fuzion with 2 black tanks only has 1 flush.

[Getn off]

Again, my Cyclone has 2 black tanks and 2 black tank flush fittings.
Troy

[geshields]

We have the Raptor 356. It has 2 black tanks. There are 2 separate flush inputs which is not exactly intuitive. In the "main" compartment where all of our water hookups/valves are is a tank flush inlet. This is the hookup for the rear tank on our particular unit.

To flush the front tank, we need to connect the water hose to an inlet next to the main entrance door on the toyhauler by the freswater drain vent.

Took some trial and error on our part to figure all this out as our dealer was clueless....

[Madcap]

Hello,

I own a 2021 Raptor 429. Two black tanks with one flush port.
After the port the lines split and go to both tanks. Yes, you have to flush both tanks at the same time. Forced efficiency

[jxnbbl]

This will be the day...the first time I will flush both tanks on my new trailer. I did spend the time to figure out the tanks used by each water source before we left....did this in conjunction with sanitizing the water system. Once in a trailers life opportunity to just open up the waste valves and view which tank was discharging which sink.


Question - when setup do people use the "Y" sewer hose connectors? Any tips there. I bought one...but not sure I'll use it on this trip as it is only myself and my wife.

[JRTJH]

Originally Posted by Madcap

Hello,

I own a 2021 Raptor 429. Two black tanks with one flush port.
After the port the lines split and go to both tanks. Yes, you have to flush both tanks at the same time. Forced efficiency

Be VERY cautious using a "dual black tank flush system"...

If you do, make sure that both black tank valves are open before turning on the water to the flush port. It's pretty easy to see that if both tanks are being flushed, then both tanks will be filling (if the valves are closed). That means, with two tanks, usually not equally full, one will be "full to the top" faster than the other. Closing the valves or flushing the tanks with valves closed can lead to "catastrophic failure" of the tank walls and create a most unwelcome cleanup for somebody......

[travelin texans]

Originally Posted by Madcap

Hello,

I own a 2021 Raptor 429. Two black tanks with one flush port.
After the port the lines split and go to both tanks. Yes, you have to flush both tanks at the same time. Forced efficiency

Seems very odd that there's only one flush connection for both tanks?
Typically the reason for 2 black tanks is the location of toilets, one fore & one aft. With one flush port located typically in the convenience center would seem that one half of that system will run over 1/2 the length of the rv making it much less effective at flushing that tank.

[Profuzz]

2020 raptor 415 main black tank flush in with main black tank pull handle 1/2 bath black tank flush on opposite side of coach in front of the main entrance door next to fresh water tank vent .

[flyingjets]

I just bought a 2021 Raptor 429. I have two drain ports. I've been on one camping trip and went to the drain station. I have two gray tank handles and one black tank handle. I placed a clear drain valve on the rear drain with no hose hooked to it. I pulled all the handles and nothing showed on the rear drain. I've called the dealer and asked what that rear drain is connected to; their answer was "DUH." Does any of you out there know what the rear drain is hooked to? My In-command panel shows one black and two grays.
Flyingjets

[Essvar]

Originally Posted by flyingjets

I just bought a 2021 Raptor 429. I have two drain ports. I've been on one camping trip and went to the drain station. I have two gray tank handles and one black tank handle. I placed a clear drain valve on the rear drain with no hose hooked to it. I pulled all the handles and nothing showed on the rear drain. I've called the dealer and asked what that rear drain is connected to; their answer was "DUH." Does any of you out there know what the rear drain is hooked to? My In-command panel shows one black and two grays.
Flyingjets

I’d take a look for an additional black drain valve under the skirting behind your furthermost rear axle. Pull that and you should see the magic happen.

As for your iN·Command. It might need an update to. Correct for your unit. The layout was wrong in mine until I had them update to the correct unit.

[flyingjets]

Well, thanks to this thread, I got the dealer off their butt. They installed new In-command software; a second black tank appeared. Then they found the 2nd black tank valve behind the rear axel. Maybe they’ll dump it for me.
Flyingjets

[Dan Lockwood]

Too late now, but my '12 Raptor 395LEV has two black tanks and two grey tanks.

The front main bathroom uses the two front tanks, one black and one grey. The galley and the half bath in the garage use the two rear tank, one black and one grey.

In the front main water center, lift the left side basement door to access the water center, and I have all the normal items including a front black tank flush hookup.

The rear black tank has a water flush hookup on the outside of the RV just behind the kitchen slide out and in front of the shore power plugin.

BOTH tanks front and BOTH tanks rear exit one main dump outlet in the center under the kitchen slide out. I have a slide valve for black and grey each in front on the main frame rail and a slide valve for black and grey each for the rear two tank.

I have no selector lever/valve. I just pull the rear black and it drains and then I shut it and repeat for the front black tank.

I let both tanks, one at a time, empty and then I shut the slide valve and flush for 5 minutes and re-drain the tank. I may do this several times to get all the crud out of the tank. Then repeat for the rear black tank. After both black are flushed sufficiently, I then drain the front grey tank and shut and then drain the rear grey tank and shut.

I do have a drain question to add to this thread. The front grey will empty rapidly and go to a trickle quite quickly and stop. The rear grey tank however, will go fast for just a few seconds and then go to a steady low flow for almost 5 minutes. Aren't the grey tanks pretty much a pull the plug and they drain versus some large flat area that just slowly trickles out the drain???

Right or wrong, this process seems to work for me. I know, if I forget the black flush hose is on, I could blow the lid so to speak. None of my tank sensors seem to work worth a hoot, so I just do the draining every few days or so. My wife seems to fill the main black tank quite regularly though...

[JRTJH]

Dan, A couple of questions about your rear gray tank 'slow emptying" and a comment for you to consider:

When you say the rear gray tank "initially rushes water" then "slows to a low flow" until empty. First, has it always done this, or is it something that's just started or is getting worse as time goes by? Is the valve for that tank a "direct rod pull" or is it a "bowden cable pull" ??? If it's a direct rod, it should fully open if the rod is the correct length and not hitting something that stops full travel. If it's a bowden cable pull, it may not be adjusted correctly. It's like the throttle cable on your lawn mower. If the "spring wound sheath" is not clamped at the correct length for the center spring rod, the throttle won't fully open or won't fully close. Your bowden cable valve pull (if that's what you have) works the same way and may need adjustment. If it's always been this way, I'd suspect the valve cable or an object in the tank that migrates to the valve opening when the tank is being dumped. If it has just started, maybe there's a "clump of grease/wax or some other thing" (maybe a big ball of fungus or mold or algae) in the tank ???

Now, the comment. For most people, the galley tank has food particles in it. They will sour and smell almost as bad as the black tank. Also, for most people, the shower gray tank is the "cleanest dirty water" and since there's no food particles, it usually doesn't sour, so it actually smells better than the contents of any of the tanks.

In your sequence of dumping tanks, you said that you empty the back black, the front black then the front gray and finally the rear gray. What you're doing, I think, is using the front gray (cleanest dirty water) to rinse the sewer hose, then putting "dirty, sour water" through that hose, making it less clean than it was.... If you reverse your gray tank sequence, emptying the shower water last, your sewer hose will be the 'cleanest it can be" without having to clean the food particles out of it....

Your sequence isn't "wrong" but IMO, could be better....

Back to the galley gray tank slow dumping, it should dump as fast as the front gray tank. So, either there's an obstruction (possibly the plastic disc that was cut to install the dump valve) or something else slowing the flow or the valve isn't opening fully. The valve opening is the easiest to check, but the stopped up drain is probably the most likely to be the problem... I'd check the easy part first (valve opening) and if that seems OK, then start looking at some object stopping the flow.

[Dan Lockwood]

Thanks John.

It's easy to reverse my grey tank draining procedure, will do! I also have a cap that I put on the sewer hose after I unhook it that I use to fill the sewer hose with fresh water from a dedicated black hose used for the two black flush ports and to rinse out the sewer hose. I fill the sewer hose several times and then slush it back an forth and then pop the vent on the cap and flush it all out into the sewer. I really take way too much time closing out when getting ready to leave the lot, but I prefer it that way.

The valves on my RV are all the slide valve with the steel rod and T handles. I believe them to be just directly attached to the slide valves at the tanks. I don't feel any type of linkage/cable in the operation of the valves.

How are the Boxelder bugs up in your neck of the woods? They were just terrible in Mt Pleasant. I think I brought back a few to MO Sunday. It was also the first really hard frost I saw this fall in MI. We're just buying property about one mile east of Jay's Sporting Goods in Clare. Going to be building a new house there. So we'll be Michiganders again! We went with friends up to Grayling last Thursday and had a late lunch at Spikes. Also took a nice drive a week ago last Saturday up the east coast and ended up in Alpena for dinner. The wife was having camper fever and had to get out for some road trippin'. Got to see Lake Huron again. On the 18th of September my nephew and niece took us over to Silver Lake Sand Dunes for the day. Lots of fun for sure and it was a great weather day to boot. Back in the late 60's and early 70's we spent many weekends per summer at the dunes. Had some VW buggies back then, not all the Jeeps and side by sides like today. Still tons of fun.

Thanks for the help on the RV!

[NapaTravelers]

I have 2 black tanks but only 1 toilet. What would the second one be for?

2012 Raptor 300mp

[flybouy]

Originally Posted by NapaTravelers

I have 2 black tanks but only 1 toilet. What would the second one be for?

2012 Raptor 300mp

If you are making that assesment from the panel that shows tank levels they often use a panel designed for 2 black and 2 gray tanks.