Heating, Air Conditioning, Fridge, HVAC/AC Sizing / Performance

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Question
I have two packaged York 3.5 ton units on my house that I bought last year. The units were built in October of 2004 and installed in early 2005. I'm not sure of the SEER rating but I believe they are 12 or 13. The house is located in Scottsdale, Arizona. It has 2,222 square feet and is two story. Both return air vents are on the second floor in the area of the stairwell. The upstairs unit has hail damage to the fins. The windows in the house were installed when the house was built in 1989 and are dual pane. Last year was our first summer in the house and the electric bills averaged $800.00 a month.

Before I start calling HVAC companies I would like to have a little knowledge on requirements, and performance of my existing units.

Is what I have too much tonnage for my square feet?
Is the hail damage on the one unit severely effecting the amp draw?
If I need to replace them, are there brands that I should stay away from?
Is it necessary to have return air on the first floor?

Answer
Jeff,

Being self contained units, the refrigerant charge is exact from the factory, unlike split systems ,where it's field charged and many times it's not charged correctly, also no braze joints you have to deal with potential leaks  or possible kinking of the line set you get an inexperience tech.installing the system, so for the reason that a packaged unit is almost idiot proof to install do not have a list of packaged unit to stay away from. Manufactures make very little of their own parts. Possible the coils and metal frame.Only one manufacture makes their own compressor. The rest of the parts are generic.

Hail damage - if the outdoor coil is severely bent over and restricting the air from going through the coil , the refrigerant pressures increase ,which increases amperage draw.You can buy a HVAC fin comb to straighten the fins if they are not severely bent,then wash coil.

At face value 7 tons is quite a lot of tonnage for 2200 sq.ft. you can buy a software package and do an accurate heat loss /heat gain calculation . One source is hvaccompters.com They advertise a residential special for $49.00

Typically if you have duct work feeding the first floor ,you should have a return(s) on the first floor.

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Joe

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40+ years diversified experience.An HVAC/Refrigeration Self Employed Contractor since 1986. NATE Certifield. Answer questions pertaining to Residential and Commercial Air Conditioning , Warm Air Heating, Heat Pump systems.Mechanical and Electrical troubleshooting of these systems.Be as detailed as possible when describing problem.Packaged unit or split systems.No appliance questions.

Experience

Installation and Troubleshooting, Mechanical and Electrical, in following areas, Refrigeration ( Walk In and Reach In Coolers and Freezers ) Commercial Roof Top and Packaged Heating/Cooling ( Natural Gas,Propane, Electric, and Heat Pumps ) Computer Room Air Conditoning Systems,Commercial Residential Packaged and Split Systems Air Conditoning and Heat Pumps.Warm Air Oil , Natural and Propane Gas Heating systems.

Education/Credentials
Graduated from Private Technical School in 1975. An HVAC/Refrigeration Contractor . Have Unlimited Heating/Piping and Cooling Contractor License.Limited Sheetmetal Contractors License.NATE Certifield. York Certifield Master Heat Pump Technician 1986. Served 33 years combination Active Duty Air Force , Air Force Reserves and Air National Guard in the HVAC/Refrigeration Shop/Mechanical Shop. Troubleshooting/Installing HVAC/Refrigeration Equiptment Worldwide. Retiring in 2003 as a Senior NCO ,and a Mechanical Superintendent.

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