What product can I use to replace a down draft venting system from a Jenair range when I have to install a range hood above a new range and wish to vent down and out of my house in the same place of the existing range vent ? Is there a range hood that conforms to this type of venting that can be installed above a new gas range?

I know that you need to install the vent but if you can pick a different location it would be better for energy efficiency because of associated downdrafts that may occur. If you can locate the vent to go through a wall to the outside it would probably be better, If that is too big a project maybe consider an indoor venting system. If you wish to use the attic assure that you add a "draft trap" (see link) and assure you clean the dryer vent pipe at least 1/yr. http://plumbing.hardwarestore.com/51-600-dryer-vent-accessories/draft-blocker-inline-damper-602022.aspx

It is possible that a down draft venting stove such as a Jenn-Air could have been previously installed and now there is this stove that doesn't need this vent system.

3.

Spillage at A.Cold chimney A.Allow heater to operate 5 minutes to create draft action.

draft hood B. Vent pipe pitches down to chimney B. Reinstall vent pipe to pitch up from heater to chimney.

C. Blocked chimney C. Remove blockage.

D. Draft hood altered D. Install factory-provided draft hood.
E. Prefabricated chimney with incorrect cap E. Install a Nationally Recognized Testing Lab (NRTL) listed vent


http://www.jandy-downloads.com/pdfs/Lite2_LJ_IO_H0248900F.pdf

I tried to copy the FL3 write up from the chart but it screwed it up a little. Look at Page 35 of the manual for a clear copy

I wish I could offer some help but I am trying to solve the same question. There are almost NO reviews out there on the internet for any downdraft vents. There are also NO noise ratings on the fans (though ceiling fans all have ratings). It would seem that the taller the vent, the better positioned it is to draw off cooking fumes but other than that and the power of the motor (and perhaps ease of cleaning), I've no idea how to select a unit. HELP!

I had the same problem. Mine was caused by liquid seeping into the infinite switch (the switch that gets rotated by the knob to set burner temperature). This caused one of the live wires to short to ground within the switch. Bad Design IMHO. Replacing the switch fixed the problem (you can get replacement parts at Searspartsdirect.com - search using the cooktop model number).
You first need to remove the unit from its installation. Start by disconnecting the exhaust fan from the ductwork. Then push the cooktop up.
To get at the switch you need to remove the top by taking off only the top row of screws all around the unit and also in the down draft cavity (the down draft cavity is where the grease guard mesh is)

I can't imagine directing the downdraft vent back up to a traditional hood type system. Why bother, just don't use the downdraft or get a cooktop without a down draft and save money.

In granite, yes for any cooktop as long as someone can cut the correct size hole. Cooktops must be installed so the top is just about flush with the countertop. They all come with a template for cutting the right size hole in the countertop.

Since Jenn-Air has been acquired by Whirlpool, there have been an explosion of problems with their appliances.
Please research your intended purchase before deciding on a replacement:
Jenn-Air info
Considering the array of early failures everyone seems to be having with appliances (US made and foreign) bought in the last few years, I couldn't even recommend a manufacturer any more.

I would think you can. Most of the cooktops are 240v and the vents are 120v, so the vent may be feeding off of one of the cooktop's hot wires. My vent is fed from it's own receptacle but is harnessed along with the cooktop's 240v.

We're buying a JES9900BAF for an island and found ducting instructions in the installation guide. Go to jennair.com and find the page for your range model. Then click on the "Specs/Literature" tab (it's about 2/3 down the page). The installation guide is a PDF document.

Thee is supposed to be a damper in the vent pipe were it connects to the hood. maybe its missing or stuck.