Evaporator coil location


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Old 07-08-13, 08:10 PM
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Evaporator coil location

Okay, time for me to ask a question.

I have a Lennox G-60 DFV furnace. (downflow) I am considering adding central cooling. Can I add a cased evaporator coil on top of the furnace? This would place the evaporator coil on the return air side.

The installation would be real easy this way vs. having to take the furnace out, set the coil and then lift the furnace on top of the coil. I think I have seen pictures of installations with the evaporator on either the return or the discharge side of a furnace. I suspect that on the discharge is better but is it an absolute?
 
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Old 07-08-13, 08:31 PM
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no, you can not do that, it will ruin the heat exchanger and is the reason why most package unit heat exchangers do not last (condensation will rot out the heat exchanger when the evaporator is before the furnace). Your furnace manufacturer and the a/c evap coil manufacturer, I am sure, would tell you that you should/could not do that.
 
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Old 07-08-13, 08:46 PM
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I do remember somewhere reading in some Lennox literature that the evaporator needed to be below the heat exchanger but I cannot find that statement now to save my life. It DOES make perfect sense.

Biggest problem is that it appears the installers bedded the furnace to the base with silicone sealant so getting that beast out might be quite a problem. Very little working room for more than one person as well as it is within 6-8 inches of the wall on one side and the back, with the water heater less than a foot on the other side. Oh, well.

Thanks, hvactechfw.
 
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Old 07-08-13, 08:47 PM
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welcome to the retrofit world of HVAC...
 
 

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