[Jacky]

I liked the covers and gave up after they came out with newer models that didn’t have a dome stop switch. It was nice to be able to leave the vent open and the rain sensor still worked.

[Ken]

I tackled the project today. Nothing was “broken”, so no replacement parts were needed.

The vent cover is moved up and down by a lever (see the picture). The gear teeth on the lever are held against a worm gear by a shaft that worked its way out of the gear box that contains the worm gear. This allowed the shaft to come loose and not raise the vent cover. Someone posted that the motor stops based on resistance, and that is what I concluded. Because the arm had become dislodged, there was no resistance and hence the motor that moves the vent cover wouldn’t stop running.

The fan motor is controlled by a micro switch which is actuated by the vent cover near its hinge. Open the vent cover, the fan motor starts and the fan spins. Close the vent cover, the fan motor stops. The Sunmullon switch apparently only controls a relay that simply opens and closes the vent cover.

All of the screws go into plastic. My plastic is almost 20 years old. It appears to still hold well. But be careful to not force or overtighten any of the screws otherwise the plastic holding them will be stripped and you’re in trouble, screws won’t hold. I used a long #2 Phillips screwdriver. Backed out the screws using a cordless driver with the ratchet set “loose”, screwed everything back in by hand. I didn’t have to unhook any wires; although a spade connector came apart that I put back together.

I started by removing the “cover” (about 12″x12″) that Liberty had installed under vent fan; four wood screws. Now you can see most of the vent fan mechanism. There is a Liberty installed “picture frame” that trims out the opening that is held in place by the four screws just removed. Easily pulled straight out.

Now you’re looking at the underside of the FanTastic unit. Three screws allow you to remove a last square cover with a large round hole for the air to flow through. A bunch of small screws (eight?) hold the screen to the main structure of the vent fan. Pull the screen down. Used compressed air to clean the screen.

Rather than repeat the captions of the pictures, go there for some more explanations.

Next remove two screws to loosen the motor assembly (which contains the manual/auto switch and the manual operation knob); one long screw and one short screw. Carefully pull the the assembly straight down.

Next remove the worm gear assembly; two screws. I used a hammer to move the shaft (piece of steel tubing with a slit down the side) back through the lifting lever and centered in the worm drive gear box. Now the vent cover lifting level was back where it should be.

(I don’t like the tubing with the slit down the side. I would have preferred a bolt with a split ring or a cotter pin to hold the shaft in place. If the thing comes apart again I’ll probably fire up the lathe and turn a better mousetrap.)

With the vent cover closed the lifting lever and worm gear assembly get installed from the bottom; turn the worm gear input shaft by hand to “extend” the lifting arm. You’ll notice that the plastic is cut out to make the install easy. Insert the free end of the arm into the long slide opening in the vent cover (the vent cover should open as you do this), and reinstall the two screws hot hold it in place.

Next reinstall the motor assembly. Once the motor assembly is in place you should test operation. It worked fine the ten times I tried it. Once in a while I would push the Sunmullon switch to cycle the vent cover/fan and it didn’t respond right away. I suspect the Sunmullon switch signals a relay and there might have been a lag in the relay running the cycle.

With the vent cover open and the fan running, I “tested” the rain sensor and it worked. I don’t think I got a picture of the rain sensor, but its probably obvious what it is when you’re looking down on the open vent/fan. If anyone wants a picture, let me know and I’ll post one.

Once I was satisfied the device was working properly again, I put everything back together; being careful not to over tighten the screws. Like so many projects I undertake on the coach, this was the first time I tackled the FanTastic vent fan so there was a learning curve to go through. Next time, if there is a future problem for this component, it will go quite a bit quicker. I think start to finish it was probably two hours.

Questions? Let me know.

[Dick]

Couldn’t post enough pictures. Here are the rest.

Note the fuse. I did NOT know there was a fuse there. It was hidden by the decorative panel that Liberty installed to “hide” the vent/fan device. Keep this in mind as if the vent fan doesn’t work, maybe the fuse if blown.

[Jim/Chris]

Nice write-up Dick!

Will remember this post in case I need to tackle this project in the future …

[Archived]

What, no champagne with the crackers and cheese?….oh forgot, in Wisconsin you drink milk.

Taht pin working out is a common occurence. I believe I used a dab of loctite on mine when reinstalling.