Frustrating leak from Fantastic Fan alteration

[AirHeadsRus]

The PO of my new to me trailer installed a cover over the FF up in front. It leaks when we get our heavy Florida thunder storms about every day. I knew it was leaking when I bought it, but thought it would be an easy fix. How the water is getting in beats me. The cover has drainage so it is not coming over the top.
I have caulked the outside twice and tried to get the inside caulked as best as I could. The latest is I put a garbage bag over the top to see if it still leaks, if it does then the problem is outside the addition. If not, I guess I'll have to tear the addition off and try to re seal it. I've been on top about ten times in the last couple of weeks. The fan works fine and if it did not have this cover could be fixed fairly easy.
Here is pic's. Anyone got something similar? If I do have to tear it off, what kind of rivets do I use to reseal?
Regards,
Joe

[Lily&Me]

The real experts here will have bigger and better info, but we finally got our Fantastic Fan/Vent leaks stopped by going all the way down to the gasket, replacing it and recaulking everything from the bottom up. There was a serious factory installation problem with ours, which may not be the case with yours-----but we would recommend taking it off and starting all over again. You might be surprised at what you find. Good luck.

[vswingfield]

That galvanized metal structure under the white plastic vent cover is obviously some homemade thing. That would be my first suspect.

Where in all that is the Fantastic Fan mounted?

I had a vent cover like that on my factory bedroom vent and had leaks there. One was probably because someone left a screw hole up there empty. About a 1/8" hole. Even after filling that I still had leaks when it rained and blew.

After discarding the vent cover and installing a new Fantastic Fan on the roof of my Excella (following FF's instructions) I am OK so far. We have had a few blowing rainstorms and everything is good so far, but time will have to tell.

That homemade chimney structure looks like leak central, though.

[AirHeadsRus]

The fan is inside the sheet metal. Looks like it was mounted properly from what I can tell but there is only an inch clearance around the top that flips up. I strongly suspect the seal for the the FF has been compromised or maybe installed improperly during initial installation. When I remove the sheet metal box, I suppose I'll have to make a patch and then put the FF seal on top of the patch. Lot of holes in the top. Might be better to put a really large patch or new panel but I don't know. The FF in the rear does not leak, nor does it have this homemade "chimney"
Thanks for the replies back.
Joe (LeaksRus)

[vswingfield]

Hi Joe,

I was concerned that the "chimney" might also be a source of leaks. I like your idea of placing a larger patch over all the holes between the top of the AS and the FF. The more holes you cover, the less can leak.

I used Alcoa Gutterseal in addition to the gasket from FF instead of Vulkem since I only need a small amount and the tube of Gutterseal more fitted my needs instead of the caulking gun size of Vulkem.

One bright side, if your leak is in front, at least it's not over the bed. I got good with a pan and a car wash sponge on my bed during leaks. Roof leaks, just for clarification.

[AirHeadsRus]

Update. It did not leak with the garbage bag over the vent. That means the leak is coming from the cover and not the outside of the mounting base. I took the garbage bag off and put duct tape along the cover seams to see if it is getting in from there. Now I'm just waiting on the afternoon thunder storm. Should be here soon. Yesterday was a real gully washer. so gave the garbage bag a good test. Thanks for the feedback & stay tuned. I measured the cover while I was on top. It is 18X18 Inch. Anyone know where they come from?
It it doesn't leak, I may just leave the duct tape up there.
Joe

[richinny]

is that a maxx air cover/scoop on top and is there a cover under there that lifts up when the fan is turned on?

[CanoeStream]

I love my Fantastic Fan. But when my cheap vent cover in the bedroom wears out I'm going to consider a complete changeover to a MaxxAir fan. You can even ventilate while underway and nothing has to shut down during rain.

It would be nice to get actual reports about how these perform in a deluge.

[klattu]

Since you still have leaks after putting the bag over the top seam...
look below at attachment point to the roof.
Best to remove all and reseal.
Vulkem, not sure if this is correct spelling, but this is just the best stuff to stick and seal.
After 20 years, mine is still flexable.

[AirHeadsRus]

Originally Posted by klattu

Since you still have leaks after putting the bag over the top seam...
look below at attachment point to the roof.
Best to remove all and reseal.
Vulkem, not sure if this is correct spelling, but this is just the best stuff to stick and seal.
After 20 years, mine is still flexable.

With the bag over the scoop klattu, it did not leak so the water is coming in somewhere inside the scoop. The "chimney" seals appear to be holding. I'm trying now to stop the water getting into the scoop.

It looks like a Max Air but I'm not sure. The FF cover opens up inside the scoop
and it may be leaking somewhere around the hinges after the water gets inside.
We may not get rain today, so will have to wait another day. It is not a really big problem now. I've got the gaucho out ready to be recovered and I'm going to take the carpet up and put in Pergo sometime before the gaucho gets back. I can bag on it to keep the water out if I can not get it to stop.
Thanks for all the replys,
Joe

[richinny]

i have the covers on my unit too but they are mounted down on the roof and not elevated. i wonder if the driving rain is blowing water up under the lid? try doing the "dollar bill test" on that seal to see if it seals well.

[mello mike]

I've installed several vent covers, including MaxAir, on two SOB trailers I've owned in the past, so I have some experience with these. This installation is bizarre, to say the least. What is the purpose of this chimney type structure?. The vent covers are supposed to mount to the vent itself or fan unit (whichever you have). The clearance between the vent cover and the roof surface should be an inch at the most.

The irony here is that the vent cover is supposed to allow you to keep your vents or fans open, even when it's raining, and not get wet.

[AirHeadsRus]

Mike,
The only reason I see for the "chimney" is to bolt the cover on. Were the covers you installed 18X18? This is like a 18X18X3.5 inch box made from sheet metal. Has about 2 inches clearance around the actual fan. If I take the cover back of, I'll take some pic's.
Joe

[AirHeadsRus]

Finally got around to removing the box and installed the fan like it should be.
The box probably leaked from the start. I have no idea why it was put on that way. Must have had 2 tubes of silicone caulk, a bear to remove. If anyone wants the box. it is free to a good home!
Joe