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McGarry and Madsen's home inspection blog for buyers of
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What size in tons is my Fujitsu heat pump or air conditioner?
Tuesday, May 26, 2020
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 Fujitsu, you should look at the first two numbers after several 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 so, for the model number AOU18R1A, 18 divided by 12 equals 1.5 tons. Another example is A0U12RLFW, which which is 1 ton.
Here’s a rundown of the range you will encounter: 09 = 3/4 ton, 12 = 1 ton, 18 = 1.5 tons, 24 = 2 tons, 30 - 2.5 tons, 36 = 3 tons.
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 Fujitsu system, go to our blog post How can I tell the age of a Fujitsu air conditioner from the serial number? For the age of another brand or manufacturer, go to our blog post How do I determine the age of my air conditioner?
And to figure out what all the other numbers listed on the condenser data plate mean, go to our blog post How do I understand the air conditioner or heat pump condenser label (data plate)?
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To learn more about heating and air conditioning systems, see these other blog posts:
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