Black Water Drain

[Jimmer]

Just purchased a 2014 Montana 3582RL and have noticed when I drain the black water it does not drain out very rapidly. On all previous 5th wheels that I have owned when I drained the black water it would completely fill the clear hose connector and gush out very fast. In the montana it fills the clear hose between 1/3 and 1/2 of the clear tube and drains out slow. Just curious if this is correct. The gray tanks flush out much faster and fill the clear connector about 3/4 of flow.

Jim Bonhote
2014 3582RL, 2006 Ford F350 Lariat, 4wd, 6.0 diesel.

[JandC]

I drain my black every 3 days or so. I generally close my shower gray for a day prior to dumping my black. The force of the black isn't as powerful as the gray. I suspect it is because there is just more water in the gray from showers and washer/dryer. I don't worry about it because I flush with the power flush feature plus I utilize the external gate valve to back flush the black tank every several dumps.

[dunrovin1955]

My black water drains fast just like the grey. This is on a 3850.

[bigred715]

When wintering in Arizona I dump the black tank every 15 days and the black tank comes out very fast. Let the shower water build up for about 3 days before flushing to help clean out hose before restarting process.

[WaltBennett]

If I'm going to dump the tanks 'regularly' (as opposed to using mascerator at home) I try filling the black most of the way. Typically only takes a few minutes filling the toilet, flushing, filling & flushing several times. If you've done that and still have slow flow, something may be wrong. I've read a couple instances of installers leaving the plastic disk inside the tank from cutting the hole for plumbing. Hope that isn't your problem!

[1retired06]

Should dump quickly. I would suspect blockage somewhere, and try filling and flushing the tank 2-3 times to clear. Another possibility, your valve may not be opening completely.

[hookman]

If you still have it on warranty take it back to the dealer and get them to check it out. I would flush it out several times before you take it in.

[DQDick]

I agree. If it's under warranty take it back in. Some owners have found things in the tank blocking the valve such as the core they cut out to put the toilet in and as mentioned it could also be the valve but it is supposed to drain similarly to the gray tanks.

[Virginia Young]

My black tanks empty a little slower than the gray tanks. We usually refill them with a hose and flush a couple times. The tank flush thingy is only on the main black tank and not on the one for the half bath. We still use the good old "fill it thru the toilet with the water hose" method on both of them. I'm a little obsessive. I can tell you - during the first 3 or 4 dumps, we were getting 2" black polyethylene fittings out of the tanks. I guess when they were building our unit, if they dropped some in, they just went and got more rather than fishing them out. They are small enough to exit the tanks, but get stuck in the hose. YUK!

[rvgeek]

Jimmer
I too have a 2014 3582, thought I had the same issue, waited until it was 3/4 full, drained the tank, ran very slow. I even took it back to the dealer for repair, the pull handles were mismarked but the tank still drains very slowly(NO blockage) and is very quiet as you stated. It just takes longer and I flush for 10-20 minutes until clear afterwards. Thought you should know

[Recumbent]

As stated by JandC above the external gate valve will allow you to back flush (by using the shower gray water), and should help clean out that black tank. We do notice a slightly slower flow on this rig's black tank verses previous Monty. Suspect placement of tank and distance of travel being the issue.

[davidaf]

I had the same issue when i compared it to my SOB fifth wheel. What i've determined is 1. The knife valve wasn't closing all the way. not much left open but just enough for some liquid to run off over time thus when emptying, what i suspected was a full tank, there's wasn't enough liquid to create that pipe filling pressure. I back flushed over and over again and opened and closed the knife until i dislodged whatever was keeping the knife from closing (and also cleaned the tank). 2. The design is different than my SOB in that to get the big rush the tank needs to be very full. My other could be a quarter full and be pipe filling fast flow, Montana not so much.

[Jimmer]

Thanks for all of the replies. I appreciate the information. It goes in Friday for inspection so I will let everybody know what I find.

Jim and Margie Bonhote
2014 Montana 3592RL
2006 Ford F350 Lariat

[Kenward Young]

As I said before, new to the form and just looking through some of the remarks. First trip out with a 2014 Mod. 3725RL could not dump the black water. Removed under belly and seen that the gate was up against the tank. Off the gate valve was a 90 deg. elbow. This went about 2 feet to a T which connected to the water from the shower tank. From there the line went to another 90 Deg. elbow to the hose drain. Black water has to pass three (3) 90 Deg. elbows. Does this make sence? I had to get a fish and work it to clear the problem. Who ever thought of this layout should be questioned.

Ken

[Kenward Young]

Sorry about that, the Mod. is a 3725RL, and yes the space is between the door and the side of the slide, about two feet.

Ken

[jcurtis934]

Yes the outlet for black tank and grey tank, after respectively valves, do 90 degree turn then to t fitting then to straight pipe and yet another 90. That's the way it is. If you have the level up system, it is real easy to elevate the front landing gear for draining of these two front tanks. Present site in georgia has dual sewer attach points, but front one is too high in elevation. Back one is what I use, but still slower than florida winter site...so I bump the front up. John

[1retired06]

blockage or your flush valve is only opening partially

[Artemus Gordon]

I always suspect a stuck "check valve"! Had three go out and slow drawing is symptom.

[Overlord]

quote:Originally posted by Recumbent

As stated by JandC above the external gate valve will allow you to back flush (by using the shower gray water), and should help clean out that black tank. We do notice a slightly slower flow on this rig's black tank verses previous Monty. Suspect placement of tank and distance of travel being the issue.

No thank you, I don't want sewage flowing back into my grey tank once they equalize! I would not use grey water to back-flush into the black tank, ....not on a bet.

[TAKPAK]

[/quote]No thank you, I don't want sewage flowing back into my grey tank once they equalize! I would not use grey water to back-flush into the black tank, ....not on a bet.

Agree, to a point. I use the galley tank to backwash the black tank, because the galley tank is elevated much higher than the black tank. Bath gray tank and black tank are side by side, at the same level. Only way I'd get black back into the galley is if the black was already overflowing out the toilet.....and then I've got way more problems. After that, use the bathroom gray tank to flush the hose.