ATF: Cyclone - Water Tank Overflow Line


Well-known member
I filled the fresh water tank with 90gal of water for a dry camp trip. Since I have been weight limited (old TV) I haven't done this before. All was well. When I raised the front this AM to hook up I had water running out from the rear of the coroplast. Evidently I put in too much BUT the overflow line is not extending thru the coroplast. Any ideas where is should be located so I don't have to remove a bunch.

Also while under it I noticed a row of self-tapping screws going down the middle of the coroplast (front to rear) that had poked holes in it. It appears at one point there had been a support something that extended from the front to the rear of the coroplast and they held it up. These screws came down from the top and the ends were sticking out thru the coroplast. Wonder how they did that??

Anyway any ideas on supporting the coroplast and finding where the drain line should be??

I'm thinking of pieces of 1x2 wood blocks abt 2-3" long screwed onto the end of the screws. I have abt 3/4-1" sticking out with 1/2" of thread showing. At least for the trip tomorrow and something else run front to back later.


Well-known member
Our CY has 2 fresh water overflow tubes together hanging below the coroplast on the ODS very close to the fresh tank drain. The two on the DS are above the coroplast and leak along the frame a couple of feet by the door steps.


Well-known member
I have 2 low point drains (red and blue) on the DS and a single blue water tank drain on the ODS. All three have cutoff valve so are not the overflow. I'm trying to figure out where the overflow lines should be extending below the coroplast so I can route them correctly and they don't overflow onto the coroplast.



Staff member
Fresh tank overflows are usually routed through the frame where they terminate in 90 degree pex fittings. Sometimes there may be a pex extension so the water drains further forward. The ones I've seen in the factory (plant #2 - LM/BH/BC) come out of the top rear corners of the fresh tank.


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    Fresh Tank Overflow.jpg
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  • Fresh Tank Drain.jpg
    Fresh Tank Drain.jpg
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B and B

I thought the same thing. I extended my overflows to below the frame. After filling I plug the lines to avoid siphoning off the top of the tank driving to the camping site in the park.



Well-known member
I wish I lost only the top few gallons - filled mine up for a trip where we knew we'd have cold weather and, therefore, planned on using water from the on-board tank. Wrong, got to destination and had less than 1/3rd of the tank as indicated by the four light gauges. Put 65 gallons into the tank at the destination before liquid started coming out of the 'vent' lines. We actually ran the pump for a while to bring the water down and stop the drainage outside.