Replacing A Roof Fan

This was the most time-consuming project I have done on the LD. I should have ordered a new rig after 5 years. That way I would never have had to do maintenance.

If you decide to do this, you will need a hot air gun and oscillating tool. Harbor Freight quality will do nicely. The sealant may look hard and brittle on the outside, but it is still gooey underneath. I think that is what makes it a good sealant. Heating the sealant while working it with an oscillating tool with a sharp scraper will make the job go faster.

There may well be a better way of doing it, but this is how I did it.

First, locate the head of any of the 28 hex screws by removing sealant with an oscillating tool. After finding one, I used an extension on the socket wrench to clear the fan frame and to allow me to put my weight on the screw to avoid rounding the head. That’s just not something you want to happen, With one screw out, measure 2.25 inches to locate the next screw and repeat 27 times. Allow 2 to 4 hours for this.

You can see some of the buried screws exposed at far left and right

Next cut the horizontal part of the flange with the oscillating tool right where it makes the corner of the vertical part of the flange. Now with a pry tool, such as a screwdriver, separate the vertical and the cutaway horizontal sections of the flange in the sticky sealant. Allow 3 hours for this task.

Even after cutting away the horizontal from the vertical, I was still not able to pull it up. So rather than spending more time prying, I put a bottle jack on the floor with a 2x4 reaching to the fan. It popped right out. 

Finish removing the sealant on the roof and clean the surface by wiping it down with MEK or Acetone. I found that MEK works and smells better.

Installing the new fan. I put down a bead of Dicor covering the screw holes. That was a mistake as I could not find the holes, so I had to make all new holes. If I did it again, I would put blocks of wood under the fan to hold it up an inch, then start four screws. Then I would put down a bead of Dicor. Maybe by having it aligned on four holes the others could be located.

Anyway after getting all the screws in. I quit. I wanted the Dicor to dry. Two days later the Dicor was still a bit gooey, but I covered the top of the fan frame with Dicor extending it out an inch or so from the frame. Just the way the Mothership did it.

Larry Wade uses 3M 5200 FC [Fast Cure] rather than Dicor It lasts forever. I had Dicor on hand.

I sprayed the roof with Ford Oxford White where the oscillation tool scratched the paint.

Vents, Fans and Covers

Vents are indispensable in an RV for helping to improve the circulation of air inside. Vents can range from a simple "hole in the roof" with crank-up cover to vents with various types of fans. On top of that, pardon the pun, are vent covers, which allow you to have the vents open for better air movement even when it's raining. You can open two vents and turn one fan to exhaust; it will draw in cool air from the other vent and push out the warm stale air. The escape hatch in the cabover area can also be considered a vent.

Lazy Daze coaches are equipped with a number of vents, some plain, some with fans. For example, a 2005 Rear Bath model has four vents; from front to back: escape hatch, Fantastic fan, plain "hole in the roof" and another Fantastic fan vent in the rear bathroom. To prevent drawing in odors from the vent stack, the bathroom Fantastic vents are three-speed exhaust models only, while the other Fantastic fans are reversible, also with three speeds and a thermostat to turn the fan on/off. On both models the screen is removable from inside the RV for easy cleaning.

Older rigs had a very simple exhaust fan vent in the bathroom, with a very noisy and a very useless little fan in one corner. These can be replaced with a much quieter Fantastic fan vent.

As mentioned in the introduction above, you can greatly enhance the use of the vents and fans in inclement weather by installing vent covers on some or all of your vents. There are a variety of models available, the most common manufacturer being MaxxAir. Although most of these covers prevent a Fantastic fan cover from fully opening, they do not seem to hamper the fans effectiveness, especially at low or medium speeds. Vent covers are easy to install; they mount with brackets to the vertical sides of the vent hatch on the roof. To make cleaning the fan blades in the vent easier, covers are available that flip open. With the simpler ones, you have to unbolt the cover from the bracket and remove it to reach the top of the fan.

Step-by-step instructions on installing a MaxxAir cover can be found the Files section of the LWALDRV Yahoo group.

There are also combination vent covers/fans that have a fan mounted up in the vent cover, rather than in the roof hatch.

There are other manufacturers of covers and vents with fans, as a look at any camping supply catalog or web site will reveal.

Other vent types include louvered vents that attach to the side of the RV over the opening end of the window.

Tips

- Attach some strips of stick-on truck-cap rubber/foam tape to the bottom of the vent cover to better seal it to prevent debris from gathering on the vent's screen.

- Before purchasing a cover for the most rearward vent, be sure it will clear the roof rail. On some models, the vent is too close to the rail and the backward-extending cover will not fit. The smaller traditional cover will fit.

Repairing a cracked vent cover

Try repairing it with Eternabond. Barry Barnes reports such a repair still holding up after a couple of years.

Contributors: WxToad, Barry Barnes

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