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DEANNADIAZ · Jun 29, 2011, 07:12 PM

We replaced our outside air conditioner 3 years ago and the technician told us it was a 3.5 ton unit. Today a serviceman went out there and told us the unit outside was only a 2 ton unit and was not compatible with the inside furnace (or coil). The unit is large and we don't believe it is only a 2 ton unit. Could someone please clarify that it is a 3.5 ton unit. It sure looks like it. The model number is #nac242akc3. We believe it is a tempstar.

wmproop · Jun 30, 2011, 04:22 PM

Haven`t dealt with to many tempstars,, but I believe it is a 3.5 ton condenser

mygirlsdad77 · Jun 30, 2011, 04:45 PM

First, why did the ac tech come out. Is there a problem with the ac? Has it cooled properly for the last three years with no issues? If it has, then it is sized correctly, bacause if there were a 2 ton condenser with a 3 1/2 ton coil, it just plain wouldn't work right. Now, that being said. I can see where the confusion on the model number came into play. It's the 242 in the number that is confusing. Here's why. 24 signifies a 2 ton, and 42 signifies a 3 1/2 ton. So, as the model number reads, is it indeed a two, or a three and a half ton? From the information I have found on the web, the compressor in your condenser unit with model number you gave is indeed a 3 1/2 ton unit. I would imagine the tech saw 24, and assumed a two ton, when in fact he should have been looking at the 42.

wmproop · Jun 30, 2011, 04:59 PM

Yes I had to Google it a couple different ways to determine which to use the 24 or the 42,, an easy one to mistake

mygirlsdad77 · Jun 30, 2011, 05:07 PM

Easy one to mistake for sure wmproop. Service mans nightmare. I have run across this a couple of times, and man does it make me cuss.

GSHeating1 · Sep 12, 2021, 10:02 PM

You can determine the “nominal” condenser tonnage of your HVAC system by examining the model number on the data plate at the side of the condenser (outdoor unit). Just like the nominal size of lumber or an air conditioning filter, the exact cooling capacity may be a little more or less than the nominal rating, but it’s close.

For Tempter, you should look for two numbers in the middle of the model number that are divisible by 6 or 12, and represent the nominal BTU of the system in thousands. A ton of air conditioning equals 12,000 BTU, and 30 divided by 12 equals 2.5, so the data plate below indicates the system is 3 tons.