Burners immediately below A coil? - InspectionNews

Michael Thomas · #1 (**permalink**) 11-01-2009, 03:56 PM

I've not before seen GFAF installed with the burners immediately below the AC coil, and can't find the Mfgs' installation instructions on line... for starters seems to me this puts a LOT of heat on the pan/coil.

Does anyone know if this installaton is correct?

Ted Menelly · #2 (**permalink**) 11-01-2009, 04:24 PM

Quote:

Originally Posted by Michael Thomas

I've not before seen GFAF installed with the burners immediately below the AC coil, and can't find the Mfgs' installation instructions on line... for starters seems to me this puts a LOT of heat on the pan/coil.

Does anyone know if this installaton is correct?

Makes no sence what so ever. Heat exchanger below the flame....Hmmmmmmm. Also the flame and hottest end of the burner right at the evaporator coil. Well the heat is being drawn down past the combustion chamber end (I guess. Is it??) and would be cooling it off...I guess.

I see no sence having the system set up like that.

Vern Heiler · #3 (**permalink**) 11-01-2009, 05:00 PM

Quote:

Originally Posted by Michael Thomas

I've not before seen GFAF installed with the burners immediately below the AC coil, and can't find the Mfgs' installation instructions on line... for starters seems to me this puts a LOT of heat on the pan/coil.

Does anyone know if this installaton is correct?

With a condensing furnace who knows what magic the engineer used to get the most efficient transfer of heat from the serpentine heat exchanger? The heat at the top of the heat exchanger will not be more than the limit switch setting, which is typically between 180 & 250 degrees F., 250 being the high end allowed by most state codes. So I don't see a problem with the location of the furnace in relation to the A/C coil.

The condensate piping is totally wrong though. The T' fitting left of the furnace cabinet does not work as a clean-out and is not capped. Definately not a vent! The secondary port does not look like it is plumbed, so if there is a primary blockage the overflow will flood the furnace.

Chuck Lambert · #4 (**permalink**) 11-01-2009, 06:13 PM

Was it set up as a down draft furnace?

Chuck

Vern Heiler · #5 (**permalink**) 11-01-2009, 06:27 PM

Quote:

Originally Posted by Chuck Lambert

Was it set up as a down draft furnace?

Chuck

I hope not! The coil has to be down stream of the furnace heat exchanger.

Michael Thomas · #6 (**permalink**) 11-01-2009, 07:36 PM

Updraft (return plenum and filter are on the the right side in that pic).

I can't figure out how the the heck they get the heat exchanger in there...

Anyone have access to the installation instructions, Mfg is "Weather King ", looks similar to Rheem units I've seen...

Vern Heiler · #7 (**permalink**) 11-01-2009, 07:45 PM

Quote:

Originally Posted by Michael Thomas

Updraft (return plenum and filter are on the the right side in that pic).

I can't figure out how the the heck they get the heat exchanger in there...

Anyone have access to the installation instructions, Mfg is "Weather King ", looks similar to Rheem units I've seen...

The heat is drawn down through the heat exchanger by the induction fan.

Michael Thomas · #8 (**permalink**) 11-01-2009, 09:28 PM

Quote:

Originally Posted by Vern Heiler

The heat is drawn down through the heat exchanger by the induction fan.

OK... that makes sense.

Jerry Peck · #9 (**permalink**) 11-02-2009, 06:11 PM

Quote:

Originally Posted by Vern Heiler

I hope not! The coil has to be down stream of the furnace heat exchanger.

Quote:

Originally Posted by Vern Heiler

The heat is drawn down through the heat exchanger by the induction fan.

Vern,

Am I missing something in that photo or are your two posts contradictory to each other for that photo?

Billy Stephens · #10 (**permalink**) 11-02-2009, 07:52 PM

Quote:

Originally Posted by Michael Thomas

Updraft (return plenum and filter are on the the right side in that pic).

I can't figure out how the the heck they get the heat exchanger in there...

Anyone have access to the installation instructions, Mfg is "Weather King ", looks similar to Rheem units I've seen...

.
Rheem makes Weather King.
.
Rheem Heating Cooling and Water Heating Products

attachment is not Your particular model.

Chuck Lambert · #11 (**permalink**) 11-02-2009, 08:10 PM

Look here

http://216.122.22.11/FetchDocument.a...c-21df65e363f3

Chuck

Vern Heiler · #12 (**permalink**) 11-02-2009, 08:49 PM

Quote:

Originally Posted by Jerry Peck

Vern,

Am I missing something in that photo or are your two posts contradictory to each other for that photo?

Heated air goes up and through the coil, flame and gas exhaust goes down through the serpentine heat exchanger and is exhausted.

(I was starting to worry that you had put me on the ignore list.)

Michael Thomas · #13 (**permalink**) 11-02-2009, 08:50 PM

Thanks!

Ted Menelly · #14 (**permalink**) 11-03-2009, 05:59 AM

I still see no reason at all why the unit has the heat exchanger below the burners. I just don't see where this could possibly benefit the system.

Also the natural rise of hot air and the venting of the exhaust gas out the flue???????? The induction motor stops and the system for some reason keeps firing...then what. To me it is like putting the damper, flue and chimney below the fire. I guess I must be thinking stricktly in the box.

Markus Keller · #15 (**permalink**) 11-03-2009, 06:08 AM

I knew that was a Rheem based on the panels, just patting myself on the back. The A-coil placement is dictated by the A-coil pan Spec. has nothing to do with how the furnace itself is setup, burners high low etc. The furnace manufacturer doesn't know whether the client is going to put AC in or not.
All of the A-coil instructions I have read stated min 9'-12" from the burners. They used to make different color plastic A-coil pans and the different colors had different temp ratings. My understanding is that has gone away and that temp and color are consistent now. Any less than 9-12" I write it up as a cautionary note to be checked out.