Uhm, new furnace will be cooking my A-coil ???

Hello all, first post here and need a little help. I had an old Interdyne(?) 55/45 furnace that has the recalled gas valve burn up on me. I was lucky to have it not burn down my home, so, now that I still have my home, I need to fix it. I looked for a gas valve and they are around $200, give or take. When I opened my big oval portal door to the furnace, I could see the heat chamber/exchanger cracking in the corners leading to the inner portion of the back wall. There was one on each side about 4” long. I knew this back a year ago, but, being a double walled unit, I figured it was good for a little while. I decided to trash that unit completely and got me a Bryant 312AAV03070 (I believe it is). I am using this as a downflow and the unit sits on top of my old evaporator almost perfect, but, I am concerned as to how far the bottom of the furnace needs to be from the AC coil. It looks as if it is the same distance as the old unit (about 5-8” give or take) but the old unit was put in 1972 and this is a new 70k unit, MUCH hotter I am sure.

I have looked everywhere but can not find a “heat exchanger to AC coil distance” notes. I have looked EVERYWHERE and its getting real cold outside. Will this be enough distance or do I need some kind of transition duct work to raise the furnace?


I much prefer to chat with folks with real names so I am going to give a real short answer NO

Does that make me less of a real person?


I believe you may receive a low airflow due to the heat exchanger being too close to the evaporator coil. You should perhaps call the furnace manufacture for specifications.

What Charley is saying is that it is an accepted practice that real names are used on this site, something about protecting the inocent or some such stuff, unless of course you have been sucking CO fumes, http://cgi.ebay.com/KIDDE-9CO5-02-Carbon-Monoxide-CO-Alarm-Detector-Batte_W0QQitemZ160291509647QQcmdZViewItem?_trksid=p3286.m20.l1116 for the past year, then there might be room for an exception:D

General speaking matching factory compontents have their clearances builtin.

I am just a simple guy, didnt think not using my real name was a big deal. Not so big someone would take such offense to it, seems a little petty to me. He could have just given a nice answer and then said “You should use your real name just for the people in the forum” or something, not act like someone beat his dog.

Actually, this is a new unit going on top of a 1972 unit. I know some are going to say replace the whole unit, but, I am strapped, REALLY strapped for cash, just cant do it and the unit I have still works fine.

Anyways, thanks for the answers so far, which that link makes me ask another question.

When carbonmonoxide detectors first came out, am I correct that they used to have a cartridge that needed changing once every month/3months/6months or something like that? Do they still have that or is there a new detector in which that is no longer needed?

Chris Marini

most here will list a 1972 unit as “at the end of it’s useful life” and I do understand about cash flow.

Living by myself, paying the rent, groceries, insurance…etc. Only have an extra $200 a month most, and that is if I am lucky if nothing else comes up, which it useually does. I cant afford a complete system, AKA matching factory units, so, I need to make sure this new furnace is sitting high enough above my old coil that it will not cook my AC coil.

To not replace the evap coil along with the furnace on a down flow system is plain old dum. So in a year or two it will be time to upgrade the condenser and evap coil and Im gonna have to remove the furnace just to replace the coil $$$$ pay day for me. an up flow coil not a problem but down flow a waist of money not to do it with the furnace change out.
The evap coils drain pan is built to hold up to high temps. upflow set up the coils drain pan is even closer to the heat exchanger then on the down flow set up.

Well, you WOULD have gotten me for more $$$ for that, but, I dont mind removing the furnace myself. Heck, if I had accsess to the freon, I would do it all myself, but…

Yes, if I had all the money in the world, logically, it would be one of the dumbest things to do.