A/C troubles started today :(


  #1  
Old 05-31-08, 07:46 PM
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A/C troubles started today :(

Hello all, I found this forum looking for some answers on how to get my ac unit functioning again.

I just came back from a week long vacation, turned on the ac and it appeared to be working fine....hours later I decided to check on the landscaping around the house, and I noticed that the ac unit outside was making a 'different' noise than the usual. I also noticed that the fan was not turning. Once I got back inside I noticed that the temp in the house had actually gone up instead of down....so I shut off the ac.

Since I have had mice problems before, I opened up the top cover of the outside unit and inspected the wires, they all look fine, other than some cobwebs. Since the cover was off and the blades were easily accessible, I spun them, they moved well. I had my wife turn the unit on, and it all worked, fan was spinning, sounded like normal. I had her shut the unit off, I put it back together, and tried it again....no go, the blower in the house turned on and started pumping air, but the outside unit was not doing anything, only softly humming. I tried to spin the blades with the screwdriver and they didn't start up...I turned the breaker off and on and it all kicked on again.

In the end, the unit doesn't start up everytime, and the procedure above using the breaker off/on method doesn't work everytime, and now hasn't worked at all.

I will list the model info below, and any advice for fixing this problem will be greatly appreciated. Thanks.

These are all the numbers I could find on the units....don't know which one you will need to know.

Also, I have a multimeter and I know how to use it just need to know what to test and what the correct measurement should be

Outside unit - house was built in 92, this was the unit at the house when I bought it 7 years ago
Tempstar - ca5036qkb1
867.830240
single phase
style number - 36mca-00089cr
serial number - L900679766
mfr number - nca5036qkb1

Thermostat
Honeywell - ct3200a1001
pf2a
9834
 
  #2  
Old 05-31-08, 10:21 PM
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Most condensing units (the outside unit) have time-delay relays to prevent short-cycling. If you turned it off and then immediately turned it back on it would be normal for it to not start until the time delay had expired. Some units have time delays up to ten minutes although three to five minutes is more common.

Sometimes there is an additional time delay built into the thermostat.
 
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Old 05-31-08, 10:27 PM
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I did not know that...I will test again in the morning and see if anything happens. Will post back with results...
 
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Old 06-01-08, 07:54 AM
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Well, this morning I switched the ac on and it worked again. I probably won't be testing the ac out today since it's pretty cool out already, but I feel better knowing that the unit seems to be functioning properly. When the unit was on this morning, it was pumping out cold air like it always had been.

When I turned it on this morning, the fan didn't start right away, I heard the unit start up, I'm assuming that it was the condenser that I was hearing, and about 30-45 seconds later the fan started up and starting turning right away...is this normal for the fan to start up after the condenser???
 
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Old 06-01-08, 12:36 PM
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I assume you mean compressor. Anyway, it is not normal for the condenser fan to start after the compressor. Both should immediately start AT THE SAME TIME.

You have either a bad capacitor and/or a bad fan motor. Do not run the unit this way. The high pressures developed as a result of the condenser fan not running may damage your compressor.
 
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Old 06-01-08, 01:04 PM
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Jim, thanks for the advice.....so what can I do to troubleshoot to see if it is a bad capacitor and/or bad fan motor so I don't replace parts that don't need it?
 
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Old 06-01-08, 02:09 PM
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First, test or just replace the capacitor. It's a low dollar part. If that doesn't do the trick, your motor is bad and will have to be replaced.
 
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Old 06-02-08, 04:47 AM
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Where is the capacitor? How does one test the capacitor?

I believe that my problem is the fan motor itself though...I played around with it more yesterday and this morning...it seems that the compressor and the motor start up at the same time, but the fan seems to get 'hung up' and won't spin at full speed. it will spin slow enough that I can count the revolutions and then almost stop...start up a little faster again, then slow to almost a stop...then it will eventually go full speed.

Bad motor?
 
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Old 06-02-08, 12:23 PM
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If you suspect that the unit is a 1992 model (it would be what 16 years old?) then I would go ahead and replace the fan motor and capacitor regardless. After 16 years the poor little fan motor has paid its dues and it is time to let it retire. If the condensor continues to be run without the fan motor coming on consistently it will suffer a much shortened life, call it cheap insurance to replace the critical fan motor. I just hope it is not to late already. Good Luck
 
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Old 06-02-08, 12:30 PM
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I wouldn't think it's too late already, I haven't run the a/c at all other than testing it since I started the thread. Even though it is mid 80's up here in michigan right now, I just have the house open and the fans running....much prefer the a/c, but want to get it fixed first...I agree with you Saturn, I already have the capacitor and fan motor on order already. I should be able to post back a few days how it all turns out.

Thanks for the help all...
 
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Old 06-04-08, 07:21 PM
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Good News and Bad News

Good news, the parts came in and I first installed the capacitor thinking that it would be silly to replace the fan motor if it wasn't really bad yet, and just keep the one I order as a spare (if I ever needed it).

Put the capacitor in, closed the unit up, had my wife turn the ac on, compressor and fan started immediately....GREAT. It was pumping cold air great all through dinner, then we noticed it wasn't getting cooler anymore. Go outside the and the fan isn't spinning.

I am assuming that the ac took the temp down, turned off, then tried to turn back on again and thats when the unit failed again.

I open the unit back up, try to discharge the capacitor, nothing happened. Both of the capacitors that I have (the original and the new one) look fine, there are no bulges, no leaks, no obvious signs of distress, except some corrosion on the terminals of the original capacitor.

QUESTION 1: what can cause the capacitor to fail/blow? - could a bad fan motor cause it, low/high voltage coming into it???

I have taken some pictures of the area where the capacitor and wiring is located. I have also tested the incoming voltage from the house to the ac unit and found that each wire coming in from the house (black and white) both have 124v. everything they are supplying voltage to from the terminal block have 124v and the red wire going TO the capacitor from the terminal block has 124v going to it.

If someone can take a look at the pictures, let me know if there is anything else I can test, or just give me another direction to go, I would greatly appreciate it.

It is supposed to be near 90 for the next few days and that won't be too comfy around the house if it actually happens.

If you need additional pictures of anything, I will take them. Thanks in advance for the additional help.

Here is the link to the pictures
 
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Old 06-05-08, 12:07 PM
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When you say the fan wasn't running, I assume the compressor was. If so, I don't think the new capacitor is bad. A more likely scenario is a bad fan motor.

The old motor initially ran because it was cool. After running for awhile it overheated and the thermal protector opened, causing the motor to shut down. It will likely close after the motor cools down (it may take some time). The only cure is replacement of the motor, just as Saturn suggested.
 
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Old 06-05-08, 01:16 PM
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Okay, so if I replace the motor and keep the 'new' capacitor in place, it will most likely work?? That is what I will try and post back....
 
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Old 06-07-08, 03:44 PM
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Could A Thermal Protector Be My Problem???

I saw one of the responses mentioned a "thermal protector" that protects the compressor(?) from overheating. My 8-year old Bryant (with a new compressor installed last September) shuts down whenever the temp reaches the low 90's, and then comes back on around 7 p.m. when the temp drops. This is awful because we are in a 90's heat wave here in Louisville. Five different repairmen have looked at it the last year and it still does it. Could the thermal protector be the culprit? Can you adjust it upwards?

HELP!!!
 
 

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