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winkydink 11-09-2006 04:51 PM

Robbing a Little Space from my Return Air Shaft
I want to install a recessed shelf unit in a wall that is one side of my return air chase.
It is of course not the side with the filter and louver.
(The filter is on the West side and I want to alter the North side.)

The return air chase is quite large and is simply a vertical shaft that is framed out of 2x4 studs and sheetrocked on the non shaft sides. i.e. the studs are visible inside the shaft. I seriously doubt that the shaft was "engineered" as to exact size needed to maximize the HVAC unit in the attic above.
The house was a medium priced track home built in the late 70s.
The shelf will eliminate approx 17 cubic ft of space.
The return shaft is approx 84 cubic feet of space.
The filter louver is 18" x 36".

How do I figure out if I can spare 17 cubic feet out of the shaft?

wink :wink:


#CARRIERMAN 11-09-2006 05:06 PM

Hi winkydink

Measure the inside dimension of the return chase, We will also need to know the model # of both the furnace and a/c unit to help determine what is necessary. Just taking the cubic feet of the space is not really of any use to us. Let us know these few things and we will help as we can.


winkydink 11-09-2006 05:27 PM

Do you want the info off the condensor or the evaporator A-coil?

The shaft is 36" x 42" x 8 foot high plus the 3 foot box overhead in attic which turns into the horizontal blower/furnace.

The shelf will be 30" x 80" x 12" deep.
Its goin behind a door to put my boots in.

wink :wink:


#CARRIERMAN 11-09-2006 07:58 PM

Hi winkydink

I would not forsee this being a problem, when we answer questions without some of the variables, it seems to come back and haunt us. The reason I needed these measurments and the equipment model # is to make sure you still had adequate return without uspseting the velocity greatly. I believe as long as the wall does not pertrude any more than 12" you should still be ok up to about five tons. I do not have my duct calculator at home though. If there is a problem with that I will let you know in the morning unless one of the other guys has theirs tonight.


winkydink 11-09-2006 11:30 PM

AC Evap Coil ; CSH 102040J; 42000BTU; Coolant=22; 500PSI;

Goodman A/C condensing unit CK 42-1 (10 seer) serial#0107475633

Singer Central Heating Unit
In attic horizontal;
Model G-H162080-12M Nat
Serial# 0240675-F49-0087
1/4 HP Motor
Max. Ext. Static pressure in Water column = 0.50



#CARRIERMAN 11-10-2006 08:15 PM

Hi winkydink

I was just reading through your list of equipment, When I got to your A/C condensing unit it sent chills down my spine, not in a good way either. You should be fine with the return air intrusion. Your current system is a 3.5ton or @ 42,000 BTU for your air conditioning. I would not reccomend protruding any further into return though. Let me know if you have any further questions, I left you a reply to your other question also.

Good luck

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