Carbon 403 holding tanks

[Carbon403]

Dealer said we have gray & black tanks in the front & garage of our Carbon 403, but there is only 2 gray valves (in the control panel & in front of the slide) & 2 black valves (one in the control panel & one behind the slide). How do you drain your tanks? (We also have a W & D hook up in the garage). And what size are all the tanks?

[bobbecky]

Your specs show 82 gallons of grey and 82 gallons of black, so not knowing anything different, I'd say 41 gallon tanks all around. Draining the tanks would be the two black tanks first and then the two grey tanks, and which black tank first doesn't matter as well as the grey tank order. You might have to look at the plumbing underneath to determine how the washer/dryer drain is plumbed, some bypass the waste tanks and drain directly out the waste outlet, and others go into a waste tank, black or grey. Our Montana bypasses the tanks and has a label that says you need to be connected to a drain to use a washer because it drains to the outlet.

[Carbon403]

I'm sorry, I wasn't clear, I know that black goes first and then gray, what I'm not sure of is how to drain the tanks. I'm unsure of which valve goes to the rear tanks, especially the gray one. When I called Keystone they said there is a gray valve behind the tires, but all I see is a black valve for the rear tanks. The only gray valves are in the control panel and in front of the slide. The black tank valves are in the control panel and behind the slide. How do I drain the gray tank in the garage? What vavles go to what tanks?

[travelin texans]

I'm reading that you're determing which tank the valve drains by the color of the pull handle?? If so that doesn't necessarily mean anything.

[Carbon403]

No, not asking about the color of the handles, I'm asking which handle goes to which tanks. The tanks in the garage only have a black handle in the back of the RV, behind the slide out. I don't see a gray tank handle back there. How do I drain the gray tank in the rear based on the handles I described & their location.

[flybouy]

Originally Posted by Carbon403

No, not asking about the color of the handles, I'm asking which handle goes to which tanks. The tanks in the garage only have a black handle in the back of the RV, behind the slide out. I don't see a gray tank handle back there. How do I drain the gray tank in the rear based on the handles I described & their location.

Let's see if I understand you correctly. You've been told you have 4 holding tanks but can only find 3 handles? If that's the case, get a flashlight and put on your dirty jeans and start looking. I've read of people finding dump valve handles in between the axles, up under the frame, and other places that aren't obvious at first glance.

If you're trying to identify which handle dumps which tank then place a clear dump extension or elbow before the hose. Pull one valve at a time and have someone flush the toilet a few times, run the faucet in the sink, run the shower, etc. until you see water flow in the clear section. Someone with an identical model/year unit could tell you the handle on the left is for X but yours could be different.

[LewisB]

Your setup sounds exactly like our 2018 Raptor 353TS. If it is, there is NO gray tank drain for the back of the trailer. The sink in the second bath drain is routed to the rear black tank. The gray tank drain under the slide is for the kitchen/galley sink drain. The gray tank drain in the water closet area is for the main bathroom sink/shower drain.

You can confirm this by draining everything, then start the 2nd bath sink and let the water run until you see one of the tanks begin to fill. In our case, it would be the rear black tank. This bothered me at first, but over the last year we have found that the sink only gets used for washing after the potty is used and the black tank does not fill up even over 7-10 days of use. So it's not a problem for us.

I'm not sure about our washer/dryer setup - we don't use it so I can't tell where it drains. Hope that helps.

[Carbon403]

Thank you, that helps a lot! We will run the water test to verify but it seems like what you described definitely sounds like ours. I appreciate it!!