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McGarry and Madsen's home inspection blog for buyers of
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How many tons is my Trane air conditioner or heat pump?
Monday, March 18, 2019
You can determine the size in tons of your Trane HVAC system by examining the model number on the data sticker at the side of the a/c condenser (outdoor unit). Look for the last two numbers of the first numbers after a cluster of letters at the beginning of the model number. It will be a number divisible by 6 or 12, and represents the nominal BTU of the system in thousands. A ton of air conditioning equals 12,000 BTU, and 36 divided by 12 equals 3, so the data plate below indicates the system is 3 tons.
Here’s a rundown of the range you will encounter: 18 = 1.5 tons, 24 = 2 tons, 30 - 2.5 tons, 36 = 3 tons, 42 = 3.5 tons, 48 = 4 tons, and 60 = 5 tons. And this is another one that is 2.5 tons.
Also, Trane is the only brand we are familiar with that occasionally lists a two-digit number for the thousands of BTU rating that is not divisible by 6 or 12—but close. The condenser below would be considered a 4 ton unit.
If you are unsure whether you have found the right two numbers, you can double-check it by looking for the “RLA” rating on the data plate. RLA is an acronym for Rated Load Amperage, and is what the maximum amperage should be when the condenser up and running. If you divide the RLA by 6 for older units and 5 or 6 for newer units, you should get a number that approximates (not exactly) the tonnage of the system. Make sure you use RLA and not LRA, Locked Rotor Amperage, which is the surge of amps necessary to overcome inertia and start the system. It averages around five times the RLA.
To determine the age of a Trane system, go to our blog post How do I determine the age of a Trane air conditioner? To find the age of another manufacturer/brand, go to How do I determine the age of my air conditioner?
To learn more about heating and air conditioning systems, see these other blog posts:
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