Cooling problem


Old 07-25-07, 07:13 PM
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Join Date: Jul 2007
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Cooling problem

Since June, my A/C is not able to maintain indoor temperature at 78 degrees. It would go up to 82-83 degrees especially during the hot weather. Long story short - HVAC contractor came to my house several times and eventually found out I have 3-ton evaporator coil while the condenser is 4-ton. He initially said my cooling system is a little undersized. He thought 4.5 ton may be better but he later said replacing the evaporator coil with 4-ton one will solve the current issue. Apparently, the previous owner was taken advantage of when A/C was installed. The house was built 6 years ago and at the time A/C was not installed. It was later added. I thought the house inspector would have caught it but I guess he did not check the coil - I wonder if it is normal practice for inspectors to check evaporator coil. Anyway, the condenser is Goodman SEER 13 and the contractor wanted to put in cased Goodman evaporator coil on top of Carrier furnace. The current evaporator coil is uncased. I thought about using Carrier evaporator coil as it may fit well on the furnace but since the condenser is Goodman so it may work better with a Goodman evaporator coil.

I'm curious if replacing the coil will solve the current problem and whether 4.5 ton cooling system would be a better choice for my house. The house is 2369 sq ft - excluding the basement and has volume ceilings; and many large windows. I did some research and came to the conclusion that 4-ton should be adequate for my house.

Any input will be greatly appreciated. Thanks.
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Old 07-25-07, 08:37 PM
Ed Imeduc's Avatar
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Id say have the tech run a AC load on the home to find out just what you need there. The other thing to check out is the furnace blower. Is it a size that will take the 4 ton or 4.5 ton AC?????
Old 07-25-07, 10:02 PM
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How do I tell whether the furnace blower can take 4 or 4.5 ton AC? It is Carrier 110K BTU (model 58PAV 111-16). The tech seems to think that replacing the coil with correct one will solve the issue.
Old 07-26-07, 04:28 AM
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You may be missing some numbers on your model number. After the 111 there should be a 2 digit number and then a 2 digit number. If indeed the last set of numbers is a 16 then you should have a 1,600 cfm blower which would be good for 4 tons of cooling.

If indeed you have a 4 ton blower then replacing the coil with a 4 ton coil will help a lot. If you leave the 3 ton coil in there you will end up killing the compressor.

A home inspector would not check the coil. But a decent inspector would have checked the temperature drop across the coil and heat exchanger. That would have given some kind of idea on how well the system was operating.

I think you'll be fine with the Goodman coil and a cased coil will look nice.
Old 07-26-07, 05:16 AM
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Location: Rochester, Minnesota
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16 in the model, That blower moves up to 1,600 CFM, so if you figure 350 per ton, = 4.5, or 400 CFM per ton, = 4 ton.

Where are you out of? Pretty large furance you got!
Old 07-26-07, 06:57 AM
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I got all info from the tech. I tried to find the model on my furnace this morning but it appears I need to take front panel off. I will do that this evening.

I live in Colorado, south of Denver. I wouldn't know if the furnace is too large or not.
Old 07-26-07, 05:07 PM
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How big is your home? Seems like a lot of cooling and heating.
Old 07-26-07, 06:37 PM
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2369 sq ft excluding basement. I'm not sure about a lot of cooling. The temperature would go up when A/C is running and it is only able to maintain 82-83 degrees in the afternoon when it is hot outside. A/C typically runs almost all day without stopping.

I checked for the model on my furnace and I have the following -

Product: 58PAV111---18116
Model: 58PAV111-16
BTU Input: 110,000
BTU Output: 89,000
Old 07-04-14, 11:16 AM
Join Date: May 2008
Location: Wisconsin USA
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First, it needs to be determined what airflow the duct system & return air filter area(s) will support.

The 4-Ton could be operated at 350-CFM per/ton of cooling or 1400-CFM.

Denver's 2.5% summer design is 91F & 59F wet bulb or a very dry climate, therefore he duct system ought to be enabled to handle 450-CFM per/ton, or 1800-CFM.

2369 sq ft excluding basement.
Well, a 3.5-Ton would have been 677-sf per/ton of cooling; probably better sizing.

Try an do a free online load-calc
Old 07-04-14, 12:04 PM
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Original thread is 7 years old. Someone piggybacked a new question and it bumped the thread into new posts. New question moved to new thread.

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