Product review (4 stars): Improved my Jenn-Air downdraft ventilation
A Jenn-Air downdraft range came with my home 30 years ago. A couple of years ago, I replaced it with a new Jenn-Air range. It worked ok until last year, when my smoke alarm went off while grilling a steak. The downdraft was barely moving any air. I put a request in on Service Magic for someone to come and make the downdraft work better. An appliance repair person came and determined that the outside wall cap was clogged up, and was the wrong type for a Jenn-Air. It was a metal wall cap with a metal wire screen on the inside. He didn't work on the vent system, so I went back to Service Magic for someone who could replace the wall cap. That turned out to be somewhat difficult because vent contractors work on dryer vents or HVAC, but not kitchen exhaust vents. One HVAC company agreed to come and look at installing a Jenn-Air wall cap that I would order online.

The Jenn-Air A406 Wall Cap is made of plastic, with a spring that keeps the damper closed when not in use. Obviously, this thing isn't going to last 30 years like the old wall cap did. The A406 was installed, and the ventilation was improved considerably. However, the test with the flow card that came with the range still fails. The flow test card is supposed to be sucked into the air vent, but it doesn't move at all. However, most of the smoke and steam does get sucked down that vent, so that's what I need.

I got a little paranoid that rats and mice could enter via the damper, so I followed up with a handyman contractor to install a critter screen over the wall cap.

This little project cost about $500 to install the $18 wall cap and critter screen. When this one wears out, I now know to call a handyman to come put in a new wall cap and critter screen. If the handyman installs the wall cap and critter screen in the same call, it should cost about $150 to get the job done.