What's under the coroplast?

[4x4van]

My daughter and SIL have a 2020 Forest River Heritage Glen TT, and there are 2 issues that I need to address. Unfortunately, both will require dropping the coroplast on the bottom of the trailer. Anyone know what's underneath (above) the coroplast?

To clarify, ALL 3 of the tanks (2 grey, 1 black) drain ridiculously slow, as if the valve is only open half way, but since there are 3 different valves, the likelihood of it being a valve issue is remote. I'd like to actually see the plumbing configuration.

Second issue is the freshwater "siphon" problem. First couple of trips were fine, but the last time, driving down the road, I noticed (while following) water pouring out of the bottom right side of the trailer. Upon stopping and looking, it was flowing out of what I "think" is either the overflow or a vent on the right side of the trailer. They had lost fully 1/2 tank of their fresh water! I plugged the line, and we continued. Shortly after, it started doing it again, this time from a line out of the bottom left side. THAT line has another line joining it thru a T before the open end. Neither of them are the low-point drains, which are found elsewhere (and marked as such). Also, this was not simply a matter of the water "sloshing" against the sides; it continued flowing full force even after stopping.

Since any "siphon" action needs the beginning of the line actually in the water, then the vent/overflow lines must be either not installed at the top of the tank, or the lines extend down into the tank. Either way is not acceptable, and I refuse to go along with the idea that we must put a valve (or cap) on the lines in order to travel with fresh water. And sadly, Forest River flat out refuses to provide me with any plumbing schematics/diagrams, either for fresh or waste water systems; they claim it's a "liability issue"...BS!!!!!!

Again, pulling the coroplast will hopefully give me some access to see just what's going on, but I'd hate to pull it and find the entire underside filled with spray foam or something, especially since there is indeed some spray foam around several locations where lines/wiring come through the coroplast. Any one pull this stuff down?

[pld33270]

Yes, pull the coloplast and see what you got. I did that years ago on a 30 day old trailer and found that the grey water tank did not have bolts installed to hold the tank in place. Glad it did not fall off during the trip from the dealer, or the shake-down trip. I had it down multiple times while I owned the trailer.

On the shake-down trip is when we discovered the bottom track of the shower door was installed backwards, allowing the water to drain into the bathroom.

[4x4van]

Thanks guys. Hopefully I'll get a chance to pull it off soon. You've given me a bit more confidence of what I'm apt to find (both the good and the bad!).

[Fisherman]

GDS-3950BH wrote:
What's under the Coloplast? A few pounds of sawdust and other debris, screws and other fasteners, possibly a half eaten sammich, and a whole lot of shoddy workmanship.

I have no doubt about that. When I took the strainers off my kitchen, bathroom and shower head, I got about a cup of wood chips and sawdust. So I would suspect there may even be a dead body or two under there.

[GDS-3950BH]

What's under the Coloplast? A few pounds of sawdust and other debris, screws and other fasteners, possibly a half eaten sammich, and a whole lot of shoddy workmanship.

[Lynnmor]

I doubt there are any blueprints, these things are thrown together by the fine craftsmen using the vast knowledge in their heads and no two trailers are exactly alike. In the RV world, water does not flow downhill, it flows in the cheapest direction possible.

The drain valve cables are probably routed wrong and not adjusted properly. Download the installation manual for your valves.

The water spilling out is a common occurrence because vent hoses are simply run straight down, see the above posts. The time that water still flowed when stopped might have been from the trailer not being perfectly level, it only takes a few inches. The vent hoses need to rise well above water level and ideally should exit the coach at that level.

Don't be afraid to pull down the Coroplast, it should be done on every trailer so the assembly process can be completed by the purchaser. You will find unbelievable workmanship and many things that need to be corrected. Wiring, plumbing, insulation and mechanical can be improved.

[TenOC]

Unscrew a dozen or so screws. Do the repair. Have someone or use some wooden blocks to hold up the coroplast and replace all the screws. No problem except holding up the coroplast so you can screw it back in place.

[WayneAt63044]

My 2013 Forest River V-Cross Vibe had the same siphon issue with the fresh water tank. The overflow/vent fitting was no where near the top of the tank on the sidewall. I re-routed that hose so that it loops above the top of the tank. Since the tank is under the chassis & under the slide out, I had to extend it forward (along the street side on my rig) to get it above the top of the tank. Now no worries. The tanks are so shallow there is only a few inches between placement of the low point drain and the vent.

The foam at the edges/penetrations of the coroplast is just to fill voids to keep the critters out and not a big issue. Mostly hollow above the coroplast on mine.

I haven't had a slow draining issue.

[MFL]

Should not be any surprises under the coroplast. Most will have small amount of fiber insulation, some have bubble wrap, or possibly extruded foam. The spray foam is just to fill holes to keep critters/bugs out.

Jerry