You probably know already that it's important to cover up a catalytic heater when not using it, in order to protect the platinum-flecked catalyst pad from dust that can lower its efficiency. Sure, you can buy a cover from your Camco/Olympian dealer... but it's stiff, ill-fitting, ugly, and costs twenty bucks. With the pattern below, you can quickly make your own from any fabric you like. A fairly heavy fabric holds its shape best. For mine, I used a brown Naugahyde-like material—fabric-backed heavy vinyl with a leather-like texture.
Note: this cover is for a wall-mounted heater. If you have a freestanding heater, you'll have to do some adapting.
The pattern shown here is for a heater that's mounted vertically (with the controls at the bottom), but I also created a version for one that's mounted horizontally. Both patterns are PDF files (Windows users: Adobe Reader required) that you can print out full-sized, making cutting easy. Here's the link to the PDF version of the vertical-mount pattern, and to the PDF of the horizontal-mount pattern; use whichever one matches the way your Wave 3 is mounted.
In addition to half a yard of fabric, you'll need a 10" piece of 1/2" elastic. Attach one end of the elastic to the bottom of each side of the finished cover, as shown in the photo at left. That'll hold it snugly in place... in fact, it'll do a much better job than the elasticized opening in Olympian's twenty-dollar store-bought cover.
You can easily make this cover in an hour or so, since it's all straight cuts and straight seams. Half a yard of fabric will be more than enough—in fact, you can probably make two, one for yourself and one for a friend!