101- old A/C system questions


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Old 04-27-16, 01:42 PM
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101- old A/C system questions

Folks,
If the a/c has a full charge, there are no leaks, filter is new, I don't believe there are leaks in the duct work but I don't know that for sure . What can conspire to prevent the system from reaching...say 74 F in a reasonable time period? Is it just a case that the compressor part just can't compress the gas efficiently? My 24 yr old unit is I believe, going the way of all flesh. She's been running all afternoon in Houston 90 F today and is just about managing to hit 74. I'll have her checked over by my A/C man but I think this is it. This happened toward the end of September last year and at the time the freon was good. I'm looking at about 5K for a full replacement....ouch! No complaints though, it's given 24 yrs of service.
 
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Old 04-27-16, 02:38 PM
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Why would your air conditioner need a full replacement because it is 24 years old?
It is possible that the repair costs could be high but your "A/C man" could make his money selling new, not repairing.

Get more than one diagnosis and repair estimate.
It would be worth the cost.
 
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Old 04-27-16, 06:58 PM
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When was the last time the outdoor coil was rinsed?

Does the indoor coil have an access panel to allow you to see how dirty it is?

A digital meat thermometer can be used to measure the air temperature at the intake grill, then at the inlet side of the furnace to help determine if you have a return air leak.

Another temperature measurement a foot after the indoor coil would help determine the condition.
 
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Old 04-27-16, 06:58 PM
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I would almost guarantee you have an airflow issue and the coil needs to be cleaned.
 
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Old 04-28-16, 06:39 AM
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101 ac

Thanks folks,
I pulled the top cover off the indoor attic coil last September and the coils were clean. At that time my AC guy measured freon, pronounced it good and then gave the outside coils a good hosing down, way better than I'd been doing them. He's coming over next week for an ac health check. I think they are a good company, let's put it this way...two years ago my prior ac man, whom I'd used for many years and knew I has some hands on savvy, said we needed a new outside condenser for the downstairs unit. I got a second opinion from my current guy who was not happy with the way the cooling fan came up to speed but apart from that said the unit was fine. He replaced the fan and touch wood the downstairs unit has been running like a champ. I'll let him do his thing next week and see where I'm at, but thanks for the info, that helps.
 
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Old 04-28-16, 12:24 PM
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The outlet side of the coil can look clean while the inlet side is very dirty.
 
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Old 04-30-16, 08:38 AM
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OK interesting stuff, thanks. I actually the indoor coil cleaning, my a/c man didn't do that. I think the way I did it was to rinse it down but from a gallon jug not a hose. That's an area I'll follow up on. Thanks for all the replies, much appreciated.
 
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Old 06-01-16, 06:19 AM
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Thanks guys. I pulled the lid and cleaned the A-Coils with 2 x cans of cleaner and a toothbrush, then misted them off with water spray. All good.
Thanks
 
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Old 06-02-16, 07:35 AM
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If the system is sized correctly on a 90 degree day the system should run well into the evening. If the unit is cycling on and off it is most likely over sized and costing you money.
 
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Old 06-02-16, 09:33 AM
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Why don't you get a delta-T of the system so you know if it is in good condition. Non stop running in Houston at 90 degree outside is not right. Just remember Houston has 100+ (can go as high as 108) temperature every Summer.
 
 

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