Condenser Replaced Thursday and AC won't shut off

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Old 07-20-13, 06:40 PM
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Condenser Replaced Thursday and AC won't shut off

Hi all!

This past week, we had 3 or 4 power surges in our home and the condenser (even though there was a surge protector on it) kept popping the fuse box and would not go on when the tech came. The unit was 5 years old and the warranty expired. He sold us a new unit. It is a 3.5 ton, 13 seer (as our old one was) ICP Day and Night R-410A split air conditioner (Na4a3). It does not have heat in it, since we live in Florida and our air handler handles that. It was installed on Thursday with a new thermostat. The AC will not shut off. It runs continuously. We usually (and please don't laugh) set it at 73 and the unit will not go below 75. We changed the thermostat thinking that was the problem but it is still happening! When we called him back to service it, he said that the unit is fine and is not sure why it is happening except that we keep it too low (which our old AC had no issue with before Thursday).

Any ideas? We will be calling another repair man but was wondering if there was anything we could do to fix this. I appreciate any information. Thanks in advance!
 
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Old 07-20-13, 06:53 PM
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We usually (and please don't laugh) set it at 73 and the unit will not go below 75.
That would have absolutely nothing to do with the thermostat. The AC will not shut off unless the temp goes below 73.

Your problem is that your AC will not cool your house below 75 during the day. It would seem that at night when things cooled off that the temperature would come down to 73.

An AC unit will only extract so much heat based on the outside temperature. You would have to measure the temperature of the air going into and coming out of the air handler....as close as possible to unit. Post what you measure here.
 
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Old 07-20-13, 07:39 PM
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I think I wrote it wrong. On the new Honeywell thermostat that we installed today, we set it to 73 and the unit would not go below 75. It stays on and will not click off. So I set the thermostat to 75 and it shut off, for 2 minutes and went back on. Now it reads 75 in the house and 75 which we set it for and the unit is still running (constantly)
 
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Old 07-20-13, 10:15 PM
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No.....you wrote it correctly.

When you set the thermostat to 75 the temperature would need to go below 75 for the AC to shut off.

I don't understand why the temperature in your house won't go below 75 degrees at night. Is your outdoor temperature currently the same as it was today ?
 
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Old 07-21-13, 07:48 AM
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PJmax, thanks for trying to help me....as a matter of fact, it was 75 last night outside as a low and as you know, in Florida that is what we get most of the time.
 
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Old 07-21-13, 08:05 AM
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If it was 95 degrees outside.....your AC may have a problem cooling your house to under 75 degrees.

But if it's 75 degrees outside......your AC should cool much lower than 75 degrees.
 
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Old 07-21-13, 08:16 AM
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Would that be the condenser problem or a thermostat issue?? I know about the 20 degree rule I am originally from NY and used to it from there
 
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Old 07-21-13, 09:25 AM
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I doubt that it's a thermostat issue, as the compressor is running, trying to cool the house to the thermostat set point of 73, while it's 75 inside. Since you're asking for the A/C to make the house cooler than it actually is, it should be running.

Have you noticed a lower volume of air coming out of the ducts than before the compressor unit was replaced? If so, it's possible that the tech didn't charge the system with enough refrigerant. That would result in the evaporator coil freezing up, thus reducing the airflow. This happened when my son had central air installed in his house. After it was installed, it would run forever and provide very little cooling. After having the installer come back a couple of times to look at it, he finally found that not enough refrigerant was put into the system. After adding more refrigerant, the system is working fine. It blows a large volume of very cold air. I only wish my 21 year old system blew that much cold air.
 
 

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