2013 Thunderbolt XLR 380 AMP (Grey & Black water Tanks)

[VICSXLR]

My 2016 420 AMP has 2 grey and one black up front and 1 grey and one black behind rear wheels... total of 5 tanks

[chpence1]

Glad yours is right.

[mnolasco]

I am new owner of a 2016 XLR Thunderbolt 5th wheel toy hauler. I am on a huge learning curve and found this thread to assist me in one of my first problems. I am parked and hooked up at a full service mobile home park that allows RVs. I have all 3 valves (2 gray 1 black) open behind the driver side storage door. However, the tank level indicator in the garage says 1/2 full, and the 1/2 bath in the garage is beginning to smell. When I run the water in the 1/2 bath sink, i dont see any drainage through the clear plastic sewer fitting. There is a label over the driver side wheel well that says "2nd gray water valve". But i cant see where the valve is. I am assuming its closed and the tank is filling with black waste with no treatment. Can anyone send me a pic of where this valve is, so I can open it? Thanks

[dhatfield6]

My valve is located on the frame, behind the plastic wheel well trim between the back and middle driver side wheel. And if the 2016 is the same as my 2013, it is not as labeled "grey water" because the toilet in the garage 1/2 bath dumps in this tank along with the kitchen sink. Let me know if you need more info.

[Kaadk]

Originally Posted by mnolasco

I am new owner of a 2016 XLR Thunderbolt 5th wheel toy hauler. I am on a huge learning curve and found this thread to assist me in one of my first problems. I am parked and hooked up at a full service mobile home park that allows RVs. I have all 3 valves (2 gray 1 black) open behind the driver side storage door. However, the tank level indicator in the garage says 1/2 full, and the 1/2 bath in the garage is beginning to smell. When I run the water in the 1/2 bath sink, i dont see any drainage through the clear plastic sewer fitting. There is a label over the driver side wheel well that says "2nd gray water valve". But i cant see where the valve is. I am assuming its closed and the tank is filling with black waste with no treatment. Can anyone send me a pic of where this valve is, so I can open it? Thanks

Just a curiosity, but when you say you have all three valves open, do you mean you always leave them open? If so, you probably shouldn't do that. There's difference of opinions when it comes to the grey water tanks, but pretty much everyone agrees the black tank need to remain closed until full. The tank needs the liquid to help carry away the solids. When you leave a black tank open, the solids fall into an empty tank instead of being submerged/suspended in water and then they start to smell.




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[mnolasco]

Yes, I have read different opinions on weather to leave the black tank open or closed. And i understand the logic. However, according to the management at the RV Park, the sewer system cannot handle large flushes, especially if several happen at once. One of the park rules for rigs with holding tanks was to leave the valves open. I may end up breaking this rule at some point.

[Kaadk]

The problem is the tank itself. If the management insists on leaving the valves open (which they shouldn't if they understood how it works) then I'd be looking into removing the tanks altogether. There are ways to get it plumbed direct which eliminates the tanks, and therefore the issue of tank build up.



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[VICSXLR]

Depending on your model of Thunderbolt location may be different but, my 420amp has a second sewer connection for the rear tanks just under and a little left of where the fuel tank fill is. Also both gray and black tank drain pulls are under there as well. I have 2 into one sewer drain.

[VICSXLR]

Black tank should remain closed otherwise solids will collect on the bottom. After draining I close valve, add about 3 toilet fills of water with a waste deoderizer drop in. I keep grey closed as well so I can use that water to flush out sewer hose after black tank dump. I am on a seasonal site and do this after each weekend of use

[VICSXLR]

I would not follow that rule...If that were enforced I would be looking for a new campground.

[mnolasco]

Thanks to dhatfiles6, I found the valve, drained the tank. the problem is that the handle is black and it blends in with the black housing. without good light, its hard to see under the pop out. I'm going to paint it yellow. Also, all 4 valves are now closed.