hole in fresh water tank

[{Tpc}]

Originally Posted by MR.M

They spin weld the fitting onto the tank . don't know of any epoxy that will work on a poly tank . you may need to get a new tank as there is no way to sandwich a fitting without access to inside the tank .

Spin welding, yay. I would bet the failure occurred as the result of some "substance" being on the fitting prior to the weld. Looks great and feels great at first, but a hard enough bump and pops right off I bet.

I think, if there is no way to adhere to the tank, I would get a fitting I could adhere the valve to, that was just an opening with screw mounts in 4 corners. Then you could drill a hole into the tank in the corners and the opening should allow enough room to secure stainless nuts and bolts? You could use silicon gasket maker of some sort to seal between it and the tank?

The only thing I don't like about that idea is i'm not sure what the effects would be on the stainless stuff sitting in water, how tight that stuff would remain bouncing down the road, and the fact you would now have 4 leak points plus the big hole.

Is there a way to block the whole off completely and then add in a small fitting to a white hose with a draincock on it for draining or something? Maybe that is easier than trying to attached the large dump valve.

[DanOB]

It is possible, but I don’t think that a manufacturer would be that kind, that there was a freeze plug in there which would pop instead of freezing the tank. You can purchase them at most hardware stores or McMaster-Carr. Or buy a expandable rubber plug from them

[Stevemal]

Originally Posted by slammer

Attachment 268137

Looks like the drain hole on mine. But, I have a gate valve attached to the hole.

[scott S]

My guess is that they put the tank in upside down to start with. When the next person went to attach the plumbing to the top they didn’t see a hole, thought it was never cut , so put a new one in the top.

[slammer]

I took a closer look this weekend. The hole is 2 inches across with a beveling in the plastic around it that looks to be 3 inches around. It's clear there was something else made of plastic that was attached, possibly glued over that hole. parts of whatever that was appears still adhered to the plastic while it's sheered off in others. so the beveling around the hole is no longer smooth.

[lilmikey_ab]

A person would have to find out for sure if it was for a drain, or if it was a mistake from factory. The picture shows that something was there, but what was it, that is the big question. If it was a mistake.. if you could find a grommet like one from a windshield washer pump, but larger, to fit, you could make something work.
The design of this grommet is intended to fit in the hole tightly, then when the pump opening is pushed in, it doesn't allow it to come out without significant force due to the little ribs in it. You'd obviously have to find the right size & then get the right size plug or pipe to fit it..
If there was a low point drain there, then, well.. that might be a little tougher to deal with, but i'm sure it's doable somehow.

[slammer]

the low point drain is a few feet down from this hole so it was not that.

[DougW]

I keep seeing people refer to the low point drain, the low point drain is normally a drain point in the plumbing pipes to aid in draining the water from the plumbing for winterizing. The picture looks like the fitting was probably the fresh water tank drain which is different from the low point drain. You should have 3 drains under the trailer; one each for hot water low point, cold water low point, and fresh tank.

[slammer]

I believe it was the fresh water drain that went in that hole. does anyone have a picture of what that looks like

[Iwritecode]

Originally Posted by slammer

I believe it was the fresh water drain that went in that hole. does anyone have a picture of what that looks like

See post #11.

[roblombardo]

A good RV shop can spin weld a fitting in there. If the crack is a problem with the same size fitting, the hole can be enlarged and the next bigger size used. You can bush back down if needed. Shouldn't be a big deal if you can find a decent shop. If you're trying to plug the hole, just place a plug in in the FPT fitting.