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Excessive Heat at A/C Air Return


JTWOODS
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Just performed an inspection on a new construction condo in downtown Dallas. The air return for the system was located in a 4th floor roof top access hallway that has no supply ducts to cool this space. The only room at the top of these stairs (2 flights) was the mechanical room with a direct vent water heater and furnace system. The outside ambient temperature at the time of the inspection was 103 degrees F. The hallway leading up to the return was 100 degrees F. How will this hot air return affect the efficiency of the cooling system? The outside unit was a York 1 1/2 ton unit and the A coils were 2 ton.

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This was the unit for the 3rd floor only which was the master bedroom and bathroom plus hallway laundry closet. The bottom 2 floors had a 2 1/2 ton unit. Total sq. ft. of the unit was approx. 1800 sq. ft.

What is the square footage of the condo?

With only one return and four floors, this in itself is going to be a problem. I would say that for any system to cool or heat properly you will want a return on each level, except at the fourth level.

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This was the unit for the 3rd floor only which was the master bedroom and bathroom plus hallway laundry closet. The bottom 2 floors had a 2 1/2 ton unit. Total sq. ft. of the unit was approx. 1800 sq. ft.

What is the square footage of the condo?

With only one return and four floors, this in itself is going to be a problem. I would say that for any system to cool or heat properly you will want a return on each level, except at the fourth level.

What was the supply air temp?

With the return air being essentially "hot" air, yes it will impact the efficiency of the system.

I don't know of any requirement that would not allow the return to be located where it is other than common sense.

I would definitely let my client know that this area was hot and that it will also most likely be cool in the winter.

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96.5 degrees was the supply temperature. The system was not cooling.

This was the unit for the 3rd floor only which was the master bedroom and bathroom plus hallway laundry closet. The bottom 2 floors had a 2 1/2 ton unit. Total sq. ft. of the unit was approx. 1800 sq. ft.

What is the square footage of the condo?

With only one return and four floors, this in itself is going to be a problem. I would say that for any system to cool or heat properly you will want a return on each level, except at the fourth level.

What was the supply air temp?

With the return air being essentially "hot" air, yes it will impact the efficiency of the system.

I don't know of any requirement that would not allow the return to be located where it is other than common sense.

I would definitely let my client know that this area was hot and that it will also most likely be cool in the winter.

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96.5 degrees was the supply temperature. The system was not cooling.

If you were only getting a 3-1/2 degree temperature drop, the system has a bigger problem than the location of it's return air opening. Once that problem is corrected, you might find that the system works just fine, even with the return at the top of the stairs.

- Jim Katen, Oregon

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96.5 degrees was the supply temperature. The system was not cooling.

If you were only getting a 3-1/2 degree temperature drop, the system has a bigger problem than the location of it's return air opening. Once that problem is corrected, you might find that the system works just fine, even with the return at the top of the stairs.

- Jim Katen, Oregon

Agreed.

Make sure you look for the combustion air for the furnace. I did a similar unit in the "M" street area that had absolutley no provision for he combustion air for the furnace. I understand the entire complex was done the same way and the boss of the HVAC company got involved and the entire complex had to be repaired.

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