How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manfuactured and modular homes
How many tons is Ameristar air conditioner or heat pump?
Thursday, March 28, 2019
You can determine the size in tons of your Ameristar HVAC system by examining the model number on the data sticker at the side of the a/c condenser (outdoor unit). Look for right two numbers in the cluster of four numbers in the middle of the model number They 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 48 divided by 12 equals 4, so the data plate below indicates the system is 4 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 for a 2 ton system.
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 date of manufacture of an Ameristar system, see our blog post How can I tell the age of an Ameristar air conditioner or heat pump from the serial number?
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To learn more about heating and air conditioning systems, see these other blog posts:
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