May 27 • 13M

We Learned How to Replace the Air Conditioner in Our Aliner Scout Camper

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“Get Devin to do it; he’s pretty handy,” said no one. Ever.

Gail won’t claim to be any handier.

So, replacing the air conditioner in our 2013 Aliner Scout popup trailer was intimidating.

We spent a lot of time on YouTube. We followed and watched a YouTube video by Rick, who also owns an Aliner popup trailer and calls his channel Going NoWhereFast. He’s replaced his a/c unit twice and made videos each time. Here’s the first. Here’s the second.

He’s clear that his method is not the standard or authorized approach—it’s just easier, and it works fine. It was certainly easy enough!

We have added a bonus step to make the installation a bit more secure. You’ll see that additional step at the end.

We tried to buy an identical air conditioner. We got pretty close. We ended up with a newer replacement model built by the same manufacturer, LG. The company designed the little 5,000 BTU a/c unit for a window in a small room in a residence, not an RV, but the old one apparently did the job for almost a decade!

Phase I: Remove the Old A/C

Step 1: Remove the upper cover mount

Above the a/c unit is a narrow slot that serves as the top mount for the unit’s cover. Ours is lost, so we’ll be ordering a custom new one. As it turns out, our new a/c unit is not the same size as the old one, so we’d need a new cover anyway. The mount could be in the way and is easy to remove and reattach.

Step 2: Clean off excess caulk

We trimmed away the old caulk using our handy 3-in-1 Caulking Tool.

Step 3: Use a putty knife to cut the a/c out of its frame, cutting through caulk and rivets

This is the essential step for removing the old unit. Cutting through the caulk is no challenge, of course. Four rivets hold the unit in the frame, two on each side. You’ll find one near each corner. You can cut the aluminum rivets easily with a putty knife; just tap the handle with a hammer.

Step 4: Remove screws inside the trailer connecting the a/c unit to the drip tray for condensation

On the bottom face of the a/c unit, there are three screws attaching the unit to the tray that collects and drains condensation. Remove those screws before you try to yank the unit out of the trailer. You’ll also want to unplug the unit inside the trailer.

Step 5: Lift the old a/c unit out of its frame in the trailer

Now you can take it out. Resist the temptation to yank it out.

Step 6: Optional: Remove the lower cover tie hooks

We removed the old, rusted hooks to replace them with new ones. You can probably skip this step if you’re happy with your hooks.

Phase II: Install the New A/C

Step 1: Bend the flanges perpendicular to the bottom of the a/c unit

On the bottom of the new unit, there are two flanges designed to help you mount it in a window. To adapt it to the trailer, you need to bend the flanges as flat as possible, perpendicular to the bottom of the unit. We used channel lock pliers for the job.

Step 2: Drill holes through the condensation tray sides into the aluminum frame

Position the tray where it belongs, tilting slightly to drain outside the trailer. To attach the tray to the trailer, drill small holes through the plastic directly into and through the aluminum frame.

Step 3: Rivet the tray into the a/c frame window

Using a pop rivet gun, insert a rivet into each of the holes you just drilled and pop it. I wish every step were this easy. We had to buy a rivet gun for this process. Here’s what we bought.

Step 4: Leading with the power cord, place the A/C unit into the frame

Being sure to insert the power cord ahead of the unit, place it into the trailer through the frame. Push it through until the flanges snugly rest against the aluminum frame. Don’t let it go without checking that it is holding in place. It wouldn’t be a bad idea to use some duct tape or something to hold the unit in place until it is secure.

Step 5: Drill holes in the flanges (do not drill into the aluminum frame)

Drill holes just large enough for your screws to slide through without catching on the threads. Don’t drill into the aluminum frame. Steps 5 and 6 are the essential steps of the installation. Be careful. Take it slow. Do it right the first time.

Step 6: Use self-tapping screws through the holes in the flanges to attach the A/C unit to the frame

We used screws with hexagonal-shaped heads and integrated washers. This screw allowed us to use a drill with a hex socket-wrench style bit to quickly install the screws through the holes in the flanges directly into the aluminum frame.

Step 7: Caulk around the three upper sides of the a/c unit along the edge of the frame

Caulk serves two purposes. First, it helps keep water out of your camper. Water entering through the a/c unit vents will find its way back out. Water that penetrates the seam may ruin your walls.

Second, the caulk helps to lock the unit in place.

Step 8: Reinstall the upper cover mount

Reinstall the upper cover mount by replacing the screws just like you found them. Adding a bit of caulk in each hole should protect the wall from moisture.

Step 9: Bonus Step! Use roof seal tape along the sides to hold the a/c unit in place

This is the step we added. This simplified installation approach relies on two screws near the center of balance at the bottom of the a/c unit to hold all the weight and keep the unit straight. The only additional support is the caulk.

Gail and I determined that we weren’t confident enough in Devin’s caulking skills to gamble for our rig. The four original rivets—two on each side—provided a much more stable mount than the two screws on the bottom.

We decided to run a strip of roof seal tape along each side to supplement Rick’s approach and lock the unit in place. Removing the tape will be messy, but we’re hoping that having it there will also reduce the number of times it fails.

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