How to Replace Your RV Vent Fan

How to replace your RV roof vent fan. Here is a detailed list of instruction with pictures.

RV vent fan replacement

Have you ever been been stuck inside where it’s hotter than the outside? It can be pretty horrible, but there is a solution. A vent fan!

20 year old Fan Tastic roof vent fan we are replacing

Most RV’s come with some sort of vent or exhaust fan in the ceiling. Our 2001 Lakota 5th wheel came with a 14′ x 14′ Fan-Tastic Vent roof fan. Turn that thing on high with a couple windows open on the cool side of the RV and instantly feel the cool air blowing through.

We also keep the vent fan running through the night on a low setting, just to keep fresh cool air circulating throughout the night. They really do make a tremendous difference. But, what happens when it breaks and you cannot repair it? We had our 20 year old Fan-Tastic Vent Fan and it finally broke.

It could not lift the cover anymore so we decided to get a new vent fan to replace it. After doing plenty of research, we decided to replace it with a new Fan-Tastic RV roof vent with all the bells and whistles.

Measure the Old RV Roof Vent Fan

Measure your old vent fan to make sure you replace it with the correct size vent fan.

How to Replace your RV Roof Vent Fan

Turn Off the Power

Turn power off to the RV roof vent fan

To start out, turn the power to the vent fan off at your RV’s circuit breaker. If the power is left on, you could short circuit the line by accident. If your positive wire hits the aluminum frame accidently, you will blow a fuse. Turning off the power will save you from using up a spare fuse.

Unscrew the Vent Fan Trim Ring

Unscrew the trim ring to the RV vent fan

Remove the trim ring to your RV roof vent fan by unscrewing the four screws on the bottom side. It should then easily slide out.

Remove the RV Vent Fan trim ring

To keep things clean, I taped a plastic bag sealing the hole from underneath using masking tape.

Remove the Sealant from around the Vent Fan

scoring the sealant around the RV roof vent fan mounting ring

Use a thin metal putty knife gripped close to the end and score the sealant around the RV vent fan’s mounting edge. Be careful not to cut too deep as to not cut through the RV roof liner.

scoring through the sealant around the rv vent fan mounting edge

Use a plastic scraper or panel removal tool to scrape the sealant off of the roof surface against the vent fan mounting edge. I highly recommend using plastic against the roof liner to reduce the possibility of damaging your RV’s roof liner.

removing the sealant around the RV roof vent fan mounting ring

Remove Sealant from the Mounting Screw Heads

unscrewing the hinge to the RV roof vent fan cover

The Fan-Tastic Vent Fan that our 5th wheel came with, had the cover’s hinge mounted over the vent fan mounting surface and screws. I unscrewed the cover’s hinge and using the help of my metal putty knife, removed the vent fan cover.

Removing the rv roof vent fan cover to expose the vent fan mounting screws.

Remove the RV Vent Fan Mounting Screws

Removing a stubborn compromised screw with the help of needle nose pliers

Our 20 year old Fan-Tastic vent fan’s mounting screws were now all exposed. Use a cordless drill to help unscrew each screw. There were a few screws that had been exposed to water and would spin free in the RV roof.

Removing a stubborn compromised screw with the help of a putty knife

With the help of a putty knife and needle nose plyers, I was able to easily unscrew each compromised screw.

Use a plastic panel removal tool or scraper to pry the old RV roof vent fan from the RV roof.

Use a large plastic panel removal tool or scraper to help free the RV roof vent fan from the RV roof. There should be butyl tape holding the vent fan mounting surface to the RV roof. A little pry here and there will help you pull the RV vent fan free.

Removing the RV roof vent fan

Clip the wires from the old vent fan and remove it from your work area.

RV roof vent fan wire cut

Cleaning the RV Roof Surface

Using a plastic scraper tool to safely scrape sealant off the RV roof around the mounting surface

Use your plastic scraper or panel removal tool to scrape as much of the old sealant off the RV roof as possible. It is not very easy but old sealant should be removed before installing the new vent fan. Be very careful not to damage the RV roof liner.

Use alcohol to clean the RV roof of oils and debris.

Use a clean rag soaked in rubbing alcohol to wipe 3 to 4 inches of the RV roof surface from the vent fan hole’s edge. I used rubbing alcohol rather than acetone. Acetone is pretty powerful and could turn the RV roof liner gooey podtentially compromising it’s sealing properties.

Cleaning the RV roof surface for the RV vent fan

Prepare the Mounting Screw Holes for Larger Screws Now if doing so

Because our mounting holes in our 5th wheel roof are 20 years old and show evidence of weather exposure, I used larger gauge screws than the ones that come with the vent fan. So I did not crack the plastic mount of the RV vent fan, I drilled larger pilot holes so the screws could just slide through without restriction. You do not want your pilot holes too big.

Make the Wire Connections of the New RV Roof Vent Fan

Strip the wires from the RV and the RV roof vent fan

You can make the wire connections a few different ways. Use Wire Crimpers and Barrel connectors to make a permanent connection, use male and female connectors for a connection that can be disconnected and reconnected, or use the twist, solder, tape method for a permanent connection. I opted for the twist, solder, tape method.

Twist solder tape method of connecting the power wires from the RV to the RV roof vent fan.

Strip the positive and negative wires coming from the RV and the new RV roof vent fan. Twist the wire strands of each wire tightly. A tight twist in the multi strand wire is always the best when making 12 volt wire connections. The twisted wires hold better when using connectors and in soldered joints. Criss cross the stripped positive wires and twist each end around the other as tightly as you can.

Twist solder tape method of connecting the power wires from the RV to the RV roof vent fan.

Use a hot soldering iron pushed against the twisted wire joint to heat the wire. Press some unspooled Rosin core solder into the hot twisted wire so the wire joint soaks up the solder. Use about 3 to 4 inches of electrical tape and wrap the solder joint tight. I used two layers of tape. Repeat for the negative wires.

Twist solder tape method of connecting the power wires from the RV to the RV roof vent fan.

Butyl Tape the RV Vent Fan Mounting Surface

Cleaning the mounting surface with acetone and a rag before applying the butyl tape

Prior to the butyl tape, clean the RV roof vent fan mounting surface with a rag soaked in acetone. The acetone will clean any body oils and manufacturing oils from the surface so the butyl tape sticks properly to the plastic mounting surface.

Use butyl tape along the rv roof vent fan mounting surface to make a water tight seal.

To help make sure you will have a water tight connection between the RV vent fan and your RV roof surface, put 3/4″ butyl tape along the mounting surface of the vent fan.

Peeling the paper backing off the butyl tape from the RV roof vent fan mounting surface

Press the butyl tape down so it sticks well. Peel the backing off the butyl tape to expose it’s sticky surface. Flip the RV vent fan over so the cover is facing up. Make sure the wires are free and hang down through the hole into your RV as you position the fan over the hole. Make sure the vent opens toward the rear of your RV and slide the vent fan into the hole in your RV roof.

Mounting the RV Vent Fan to Your RV Roof

Fill the screw holes of the RV roof vent fan with sealant before screwing it down.

Squeeze sealant/adhesive caulk into each mounting screw hole and a bead around the mount edge where it meets the RV roof to fill any gaps. This is not the final sealing. I highly recommend “Wet Seal”. It works AMAZING on RV roofs. This sealant is self leveling and stays liquid for a couple hours. It was recommended to me by Mark at Sonrise RV in Escondido, CA. I called looking for RV Lap Sealant and they said they have something way better, so I went with the “Wet Seal”.

Highly Recommend Wet Seal sealant/adhesive for sealing your RV roof

Prepare the Wet Seal sealant tube by unscrewing the caulking tube tip, cut the tip off of the tube with a razer knife, screw the caulking tip back on, and load the caulking tube into a standard caulking gun.

There is no need to poke a hole through tip, the seal is open when the tip is cut off.

Instead of using the stock screws the new RV vent fan came with, I used a thicker gauge screw to make sure the threads got a good bite on the existing mounting holes. I first had to drill bigger pilot holes in the vent fan mount so the thicker screws would not crack the plastic vent fan mount. I did this step as soon as I removed the vent fan from the box.

Screw each screw into the RV vent fan mount until snug. You do not want to strip the mounting holes.

Rain Hood Option

apply plenty of sealant to the rain hood mounting bracket that is to contact with the RV roof vent fan mounting surface

If using a rain hood, follow the mounting instructions. The mounting hardware that came with the rain hood we chose went on the second to first and last screws on both the driver’s and passenger’s side of the RV vent fan mount. Put a good amount of Wet Seal sealant around the screw hole on the mounting bracket surface that will come in contact with the vent fan mounting surface.

screw down the rain hood bracket, not too tight

Make sure to fill the screw hole in the vent fan mount with sealant first. Place a screw through the screw hole in the rain hood bracket with the sealant facing down. Place the rain hood bracket sealant side down onto the RV vent fan mount so the screw slides into the empty screw hole. Tighten the screw down so it is snug. Sealant will squeeze out from the edges of the rain hood bracket and screw head.

screw down the rain hood bracket, not too tight

Squeeze plenty of sealant under the rain hood mounting bracket so the space is completely filled with sealant. This makes a water tight seal.

Fill under the bracket with plenty of sealant

Mount the Rain Hood

I really like the idea of having extra protection for the roof vent fan. Not only is this a how to replace your RV roof vent fan but a good idea of what to include with your replacement for longevity of your investment.

Slide the rain hood down onto the mounting post of each mounting bracket

Remove the protective plastic from the RV vent fan cover. Place the rain hood over the RV vent fan so the posts on the mounting brackets go through the mounting holes in the rain hood foot’s edge. Make sure the open side of the rain hood faces to the rear of your RV. It is easiest to do one side first and then adjusting the posts in the bracket so the other side will slide onto the posts of each remaining bracket.

Put a supplied washer and safety clip on each post to keep the rain hood mounted.

Slide a supplied washer onto each mounting post. Then slide a safety clip through each hole in each mounting post.

Rain hood installed onto the RV roof vent fan

Seal the RV Vent Fan to the RV Roof

Sealling your RV roof vent fan with Wet Seal sealant.

Go around the edge of the RV vent fan mount with the Wet Seal sealant doing a zig zag motion to lay a 1 inch wide bead of sealant, 1/2 inch over the vent fan mount and 1/2 inch on the RV roof. Cover the screw heads with sealant as well.

Sealling your RV roof vent fan including the screw heads with Wet Seal sealant.

You can use your putty knife to softly smooth the top of the sealant bead to make sure there are no air gaps. Be careful no to push down because you do not want to remove any sealant from the RV vent fan mount edge.

spread the sealant to eliminate air bubbles without removing sealant

Install the Trim Ring on the Bottom Side of the RV Vent Fan

Install the trim ring into the ceiling

Slide the trim ring up through the hole in the ceiling and into the vent fan. Be careful not to pinch the power wires. I used a small square of butyl tape at each corner to hold the trim ring in place. Keep the butyl tape at least 1/8 inch from the edge so it does not squeeze out. Put a screw that came with the vent fan onto your phillips screw driver or cordless drill phillips head bit.

screw the trim ring to the ceiling using the existing holes.

Push the screw into a screw hole in the trim ring, wiggle the screw back and forth until the screw tip finds the existing screw hole and tighten the screw. Repeat for the remaining three screws. Make sure to tighten until snug, do not over tighten. You do not want to crack the plastic trim ring.

Test the RV roof vent fan.

Test out your new RV Roof Vent Fan.

Fan Tastic RV Roof Vent Fan

That is how to replace your RV roof vent fan.

Product and Tools Used for This Install

In order to replace your RV vent fan, you need specific tools. I use these tools for many different RV repair and maintenance jobs. I highly recommend having these tools for your RV roof vent fan replacement.

Fan Tastic RV Roof Vent Fan similar to the one we bought. A roof vent fan with thermostat, automatic temperature setting, manual speed settings, and rain sensor, blow in or out switch, no remote.

Fan Tastic RV Roof Vent Fan three speed settings, no remote

MAXXAIR MaxxFan similar to Fan Tastic Vent Fan. Remote displays: temperature setting + the actual inside temperature, fan on or off, vent open or closed, fan direction. Remote controls: temperature, speed (10 speed settings), on and off. I personally think this fan is a great buy.

Rain Hood/Cover for RV Vent Fan

Wet Seal Sold at Sonrise RV (760) 745-2444 The best sealant for RV roofs and roof accessories. The guys at Sonrise RV in Escondido CA are incredibly knowledgeable and very helpful. I have been to other RV repair and parts businesses and they do not even begin to compare to Sonrise RV.

Dicor Self-Leveling Lap Sealant, 4 Pack A good alternative to Wet Seal if Wet Seal is unavailable.

3/4″ Butyl Tape Great for creating weather proof junction between panels/mounting surfaces

Auto Trim Removal Tool Set (12 Piece) Great set for scraping, prying, leverage, opening gaps between panels, and removing panels. I love this set. All tools but one are non marring plastic tools.

Makita 18V Hammer Driver-Drill, Impact Driver, Charger, and 5 amp battery with tool bag Great quality 2 speed drill and impact driver with a big 5 amp battery for big jobs.

Electronics soldering iron kit comes with all of the tools needed for electronic soldering work.

2″ Flexible Putty Knife

Needle Nose Pliers

Rubbing Alcohol for cleaning oils off RV roof material

Acetone for cleaning oils off mounting surfaces

Barrel Connectors for permanent wire junctions

Male and Female Connectors for disconnectable wire junctions

Channellock Wire Crimping Tool Needed for using connectors

Watch the Step By Step Instructional Video Before you do it Yourself

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