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Most Convoluted and Inefficient Install Award


Inspectorjoe
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Yesterday I had a good-size 1986 Tudor. During my initial tour of the property I noticed both heat pump outside units were manufactured July 2007 and the basement indoor unit was a month older. I shouldn't have much to do as far as HVAC I thought. One thing was strange though - the airflow at all of the registers on the second floor was very anemic and not very cool.

It was 90 degrees and sunny. When I finally got up into the attic nearly 5 hours into the inspection, my breath was taken away - not by the heat, but by this train wreck of a duct system. What on Earth were they thinking?

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Outside air temp was 90. I didn't check the attic temp, but it wasn't too comfy. After running full-tilt for nearly 5 hours, the system couldn't get the second floor lower than 85 degrees. At the plenums, the return temp was 87.1 and supply temp 60.7.

Just had to share.

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A common test I used in hot weather is to turn the thermostat down to about 60 or less to make sure it doesn't cycle off. I then set my thermometer on the kitchen CT or elsewhere and let her run for the duration of the inspection. Fairly often I'll get a zero drop in temperature after 2 - 3 hrs of continuous operation with the indoor temp in the high 70's. When I get that, I write it up very simply: HVAC system is not functioning as intended. Who could argue with me? It ain't a heat wave. AC is supposed to cool the house and it isn't.

Marc

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A common test I used in hot weather is to turn the thermostat down to about 60 or less to make sure it doesn't cycle off. I then set my thermometer on the kitchen CT or elsewhere and let her run for the duration of the inspection. Fairly often I'll get a zero drop in temperature after 2 - 3 hrs of continuous operation with the indoor temp in the high 70's. When I get that, I write it up very simply: HVAC system is not functioning as intended. Who could argue with me? It ain't a heat wave. AC is supposed to cool the house and it isn't.

Marc

If the house is vacant or if the AC hasn't been run, and if it's very humid, it might take longer than 2-3 hours. The AC has to remove the humidity before it can produce any meaningful cooling.

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A common test I used in hot weather is to turn the thermostat down to about 60 or less to make sure it doesn't cycle off. I then set my thermometer on the kitchen CT or elsewhere and let her run for the duration of the inspection. Fairly often I'll get a zero drop in temperature after 2 - 3 hrs of continuous operation with the indoor temp in the high 70's. When I get that, I write it up very simply: HVAC system is not functioning as intended. Who could argue with me? It ain't a heat wave. AC is supposed to cool the house and it isn't.

Marc

Wouldn't it be better to check the room temperature on the thermostat, rather than at the kitchen counter? Provided the thermostat is properly located?
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Jim's right. I'd use some other method to get a feel for the performance of the AC system if the house were vacant.

Neal, it doesn't matter much to me where I check the temperature. I try to use common areas such as kitchen, living or dining rooms. Each should experience a drop in temperature if the AC runs non-stop for 2 or 3 hours.

Marc

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Could be something simple too like a dirty filter, dampers being closed...

I don't think you can make a call whether the a/c is working properly just by seeing if the room temperature drops - too many variables.

In Joe's post the a/c could have been working great but the air distribution system is crap.

Hello Terry,

I define HVAC system as including the ducts. As an inspector I don't care much for determining whether an AC issue is with the ducts, air handler/furnace or condenser unit or all of the above, though I do check many particulars such as filters, coils, ducts, etc. I guess what I'm saying here is that I often see the whole system in such a big mess that I just write it up once and make my recommendation for review/repair by a contractor. The test that I do gives me foundation that few can argue with. This is what I would have likely done with Joe's OP.

BTW, my Fluke 971 measures humidity as well as temps, which I may also chk if temps haven't dropped.

Marc

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Yesterday I had a good-size 1986 Tudor. During my initial tour of the property I noticed both heat pump outside units were manufactured July 2007 and the basement indoor unit was a month older. I shouldn't have much to do as far as HVAC I thought. One thing was strange though - the airflow at all of the registers on the second floor was very anemic and not very cool.

It was 90 degrees and sunny. When I finally got up into the attic nearly 5 hours into the inspection, my breath was taken away - not by the heat, but by this train wreck of a duct system. What on Earth were they thinking?

Click to Enlarge
tn_2011712223031_1%20192.jpg

60.92 KB

Click to Enlarge
tn_2011712223118_1%20190.jpg

57.81 KB

Click to Enlarge
tn_2011712223255_1%20212.jpg

51.34 KB

Click to Enlarge
tn_2011712223341_1%20185.jpg

50.66 KB

Outside air temp was 90. I didn't check the attic temp, but it wasn't too comfy. After running full-tilt for nearly 5 hours, the system couldn't get the second floor lower than 85 degrees. At the plenums, the return temp was 87.1 and supply temp 60.7.

Just had to share.

"the boss says as soon as we use all this duct, we can go home"

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