Whole House A/C stopped cooling Trane XE1000

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Had been running fine for whole day, increased the thermostat little bit to give it a breather. After couple of hours I realized that it was no longer putting out chilled air. Went outside and verified that the condenser blower fan was working but the Freon line is not chilled.

- So we know house thermostat is calling for A/C on
- Inside blower air handler is working
- Inside filter has been cleaned
- Outside condenser fan is running

How do I verify the compressor is running or not?
What controls the compressor to turn on?
Don't both the blower and the compressor get the same power?
If one is on, the other should be?
Does compressor gets it own capacitor?

I don't think it just ran our of Freon. That would have been more gradual. This was like house went from bone chilling cold to not chilling any more. Slow Freon leak would have noticed by low performance of the A/C.

So I am hoping it is something electrical. But since the entire unit sits outside, it most likely does NOT have any sensitive electronic parts inside it. Although it might still have some relays or cutout switches etc?

And please, don't give unsupported and stupid suggestions like "are you sure you have power to your A/C" etc!
 
The thermostat usually energizes a 24 volt relay in the outdoor unit that turns both the compressor and fan on. If the fan is running, then at least it's being energized. The contactor for the compressor could be bad, or you may have lost a motor capacitor. If it's an old unit it's possible some connections got old, corroded, and burned up. Look for scorched wires, especially where they connect to relays or capacitors. You might check the compressor after it's been running for a few minutes and see if it feels warm. Turn the power off first. The fan motor may or may not be 240; it could be a 120 volt motor but the compressor is nearly always 240 volt. Rarely does a winding on the compressor fail, but I've seen one fail that way.

Just occurred to me; turn off the cooling and cycle the A/C breaker. The compressor I had fail was in a 240 volt window unit. It actually tripped one side of the breaker, and the fan motor was indeed a 120 volt motor that was running on the other leg. I remember now, the compressor winding shorted to ground but it only tripped one side of the breaker.
 
Thanks for good suggestions! I presume I will have to take the panel off from the outside condenser unit to see the compressor or the capacitor. Is there any way for me to manually push the compressor to start if it is bad capacitor or is the motor and compressor drive shaft all internal and there is nothing to push start it?
 
Yes, and turn power off at disconnect before you open the panel.

You cannot push anything to start.

Capacitor should be cheap, as in under $50 or so.
 
If the capacitor is bad, I think you will hear a hum on the outside unit. You can use a long screwdriver and push the fan blade manually and see if it starts to turn after you push the fan blades.

Also make sure you hose off the fins of the outside unit. That impacts performance of the A/C. Did you replace the AC filter as well?
 
Bad capacitor usually bulging on the top where the connectors are located.
Even a slight bulge indicates bad capacitor.

Match the value and buy Made in USA Amrad capacitor from Amazon or Ebay.

There are usually 3 capacitor (2 of them can be combined into 1).
The run capacitor (1 each for Compressor and Fan) and the start capacitor (usually relatively high capacitance).

If the fan is running but not cooling, chances are the capacitor for the compressor (running or start) is bad.
Then again, it may be a combined capacitor so you need to replace it.

A good AC person should be able to help you very fast if it is something else.
Choose a person that own and operate the company himself, not big company which will tell you to change the whole thing.

Check Youtube, there are a lot of video on home HVAC system diagnosis.
 
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On my old heat pump, they failed every 4 years or so. So I changed them every 3 years and never had a bit of trouble.

Your life time may vary. They are cheap, so keeping one is stock to save waiting for a repairman is a good strategy.


Rod
 
Should look into installing a hard start kit while you are at it. Right after we moved into this house last year, the a/c stopped getting cold. The landlord had a guy come over and check it out. The condenser fan was running but the compressor was not. He could hear the compressor trying to start but it couldn't. He cut the power and installed a hard start kit and since then, we haven't had a problem with it.
 
I ordered replacement for Trane CPT01032 / CPT-1032 • 40 + 7.5 uf / Mfd GE GenTec Made In USA capacitor. It has 3 different connections marked "FAN", "C" and "HERM"; supposed to arrive day after tomorrow.

The A/C guy is coming the day after that. Hopefully, I will be able to fix it before and cancel the call.

If not, it is only $20 part. The A/C guy will probably charge me at least $200 just to show up. If it comes to that, I will ask him to install hard start kit.
 
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Originally Posted by Cujet
Not a bad idea to check for pressure. My system recently had a wire chafe against a copper tube, liberating 14 pounds of R22.

Even though I live in a partial Federally funded apt. this just recently happened to my a/c. A wire to the compressor shorted out on the freon line, blowing off all the freon and burning up the compressor. I now have a new TRANE system, condenser, AHU, wiring, copper, and digital t-stat. The best part about it is, it's more energy efficient than the last unit, and I didn't have to pay for ANY of it.
 
Outside where the capacitor is, there's an energized magnetized type relay switch. With a screwdriver push it close, if the compressor goes on then the capacitor is bad, about $15-$20. Any brand capabilities will work, you need to have the micro farads.
 
You guys were right. It was the capacitor but the one I had ordered was the wrong one. Fortunately, I was able to source it locally and do the swap which took less than 15 minute from start to finish. I presume an honest HVAC guy would have billed close to $250 and I would have paid that amount gladly.

But more likely, a generic HVAC guy would have showed up and started poking around and would have said I don't have the part and besides you need to put Freon in it and the condenser is all shot and since this is a 20 year unit, it is not cost effective to fix it and we need to install $8K new unit.

Just like auto mechanics, HVAC technicians are not born with a honest bone in their body
grin.gif
No offense to the honest ones but I bet they are as rare as hen's teeth.
 
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Just went through this. I have a post about it. I had a dual capacitor that ran the fans and the compressor. Yours may have one for each. It's really easy to replace. If you have some pictures. It's usually on the same corner where the ac lines go in. You can take it out and verify the right one if you haven't already
 
You guys were right. It was the capacitor but the one I had ordered was the wrong one. Fortunately, I was able to source it locally and do the swap which took less than 15 minute from start to finish. I presume an honest HVAC guy would have billed close to $250 and I would have paid that amount gladly.

But more likely, a generic HVAC guy would have showed up and started poking around and would have said I don't have the part and besides you need to put Freon in it and the condenser is all shot and since this is a 20 year unit, it is not cost effective to fix it and we need to install $8K new unit.

Just like auto mechanics, HVAC technicians are not born with a honest bone in their body
grin.gif
No offense to the honest ones but I bet they are as rare as hen's teeth.
Would you believe that the replacement lasted less than 3 years? I was raking my brains and trying to remember what was the exact symptoms and solution the last time.

Fortunately, BITOG remembers! I was not at the house when the A/C was started yesterday but it was working and once the house got chilled, the thermostat was bumped to hot zone. Later when I arrived and bumped it back in to cool zone eventually I realized that registers were pushing out barely cold air.

Looks like I have yet another project today. I do have spare capacitor which I had ordered from Amazon 3 years ago. I am hoping it is indeed the capacitor that needs to be replaced. I am really disappointed that original lasted to close than 20 years but the replacement from a professional parts store did not make 3 years.

Funny thing is I was trying to get back to my old text messages from that time with my brother to figure out what had happened three years ago but after scrolling endlessly for 10 minutes as I came closer to those dates, the iPhone text app froze! After sleeping it over, I thought I must have also asked the BITOG for help at that time.

BITOG is like my personal diary. For example, I can tell you when was the last time my vehicle was washed and waxed? (answer: more than years ago :)
 
Less than 3 years!
thumbnail_IMG_2413.jpg

Now waiting for the house to become comfortable again in few hours.

Of course, I immediately ordered a new spare one. I do wish I had taken more pictures of the unit while I had the cover off. There must be another capacitor for fan there and I should get its specification so that I can pre-order it. The circuit diagram for the unit does not give values for the capacitors.
 
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