Hooking Up the Down Draft

We moved here in the spring of 2007. I have a down draft Jenn-Air® slide-in range with down draft system (more here). Hooking up the down draft in our previous house was as simple as attaching the down draft to the floor the going through the outside vinyl sided wall. It took minimal effort and about an hours worth of time. Here it was a different story. The house is earth bermed with the lower, main living level mainly below ground. That meant the vent had to go through a cement foundation wall that was about 12" thick and on the only on ground level. So the vent would span from the lowest level exiting on the ground level. This past weekend we decided to hook-up the down draft after securing the necessary equipment to do so. It was a DIY project.

Our first step was work in the walk-in pantry that is below the only room on the ground level which is a large entrance. We marked out the area in the pantry where the vent would be going through then carefully dug around to make sure there were no wires (1). Next we used a 4" cement drill bit (2) and marked on the outside (3) where we would be drilling. We decided drilling from the outside in would be a lot less mess indoors and it would keep the noise for the most part out of the house.

The drill bit was attached (4) to the heavy duty drill then we started drilling. I'm telling you drilling through cement is very loud, dusty work and slow going work. You definitely need ear plugs and don't push the drill. Let the drill do the work for you without forcing it.

The drill went through the cement foundation wall (5) in about 4 inch segments. This actually took a lot more time than expected as you just can't rush the drill. Once the drill hit that mark my husband wacked out the plug (7) with a hammer and huge screwdriver. We ended up with 3 full sections of plugs plus a small one. They looked like the big beads the Flinstones might have worn! Then he drilled further until he finally broke through (6). Breaking through really meant we were able to free the hole of any debris and not actually drilling completely through. Had we drilled completely through we would have had quite the mess in the pantry! At the end of Thursday night we were left with a nice hole in our foundation that spanned from the outside into the pantry. We stuffed the hole with an old towel and called it a night. My husband was sore and achy from running the drill and it was getting hot an humid out so we figured on finishing the hook-up over the weekend.

We had all the materials ready for the hook-up that included rigid ducting, flexible ducting, elbows, a reducer, eco-friendly vent cover and metal duct tape (9). The first step was to install the eco-friendly vent cover on the exteriour (10) in the duct lined hole (11). This is a special Canadian made vent cover that is heavily insulated and saves energy (more here). I should mention when doing this type of DIY project go as energy efficient and eco-friendly as possible even if it costs a bit more. The vent cover is not only heavily insulated but during insulation a heavy application of caulking is applied assuring no air leaks later. The insulation and automatic valve closure via a specialized floating ball means there will be no transfer of cold air into the interiour of the house during the cold weather. The automatic valve also ensures that rodents and insects even if they somehow got through the vent grate system would not be able to get into the vent pipe itself.

The down draft system of a Jenn-Air® is an extremely powerful venting system. The main blower that moves the air to the outdoors is attached to the floor (12) which means moving these types of stoves is not quite all that easy. The back of the down draft (13) is the main area of interest. A short flexible metal hose runs from the air intake to the down draft exhaust (not shown but basically in line with the plug in 12). A rigid duct pipe runs from the outside vent (14) to the down draft exhaust (15). Each bend is carefully sealed with metal duct tape to keep the velocity in the duct.

The actual opening of the Jenn-Air® down draft (13) is 5" but we used an adaptor to reduce that to 4" for two reasons. First we wanted to us the high efficiency vent cover by Braun which in our climate saves a lot of money and second by reducing the duct size we increased the velocity of air being expelled so increased the efficiency. Unlike a dryer vent there is no concern over lint build-up either so the ducting should stay relatively clean.

Once everything was hooked up we gave the down draft a test run. Oh my, it was wonderful! Surprisingly it was a lot quieter than the last installation and in fact is barely noticeable when turned on. The stove is now 100% fully functional. I am a very happy camper!

Garden Gnome
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