AC blows cold for one hour, then blows warm

Problems related to residential installations.

AC blows cold for one hour, then blows warm

Postby jtarrant74 » Tue May 31, 2011 9:44 pm

I have a 1993 Carrier 2.5 ton 9 seer unit. It will blow what seems like good AC for about an hour, then it will continue to run, but not be cold at all (not hot persae, but def. not cold). In fact, it ran all night and while the internal temp of the house started at 85, it cooled to 80 after 8 hours straight. When it cools down after a few hours, I can restart the AC and it will repeat (one hour of cool and then blows room temp air). I had it evaluated today and am told that the problem lies in the compressor. It gets too hot and then has a safety switch of some kind that trips when the compressor overheats. He suggests a new unit (Payne $4200 or Carrier $4700 total install price of new inside/outside unit). He estimates the compressor repair at $1300. So I have two the compressor issue feasible or could it be something else that would cause it to cool for an hour and then blow uncooled air? And two, is it time for a new unit or is it worth replacing the compressor?
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- AC blows cold for one hour, then blows warm

Postby nomadpeo » Sat Jun 11, 2011 5:03 pm

although it's old, if a minor issue can be resolved to get a little more goodie out of it, it's worth finding out why it's overloading, like the duke said. i'm late responding, but maybe somebody else can benefit. freon level, capacitors, burnt wires, burnt contactors, dirty coils can all cause overheating. a failing start relay can also cause a problem resulting in overload. never hesitate to get a 2nd and 3rd opinion. some just want to sell and make money. some of us want to do honest service work and gain a permanent customer. when it's time to replace, be connected to someone you already trust.
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- AC blows cold for one hour, then blows warm

Postby Braut » Tue Jun 14, 2011 7:25 pm

Definitely check the basics before jumping into replacing/repairing the unit... this largely depends on how much you trust your contractor as well. If the compressor is truly overheating definitely make sure the condensor and fins are not dirty preventing the unit from properly dissipating heat. Make sure the fins around the coil aren't bent as well.

Good luck
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- AC blows cold for one hour, then blows warm

Postby einstein » Mon Sep 05, 2011 11:38 am

Must be checked before replacing.
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- AC blows cold for one hour, then blows warm

Postby heatseeker » Tue Sep 06, 2011 9:19 am

replace it its 18 years old. you will regret it in the long run. upgrade now.
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