Photograph of  This new compressor was placed directly against
a brick wall. One third of its condenser coil cooling ability was blocked. Air Conditioner Compressor Hard Start FAQs
Q&A on diagnosing, fixing an AC compressor that has trouble starting

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Q&A on hard-starting HVAC compressor motors:

These questions & answers about hard-starting air conditioner or heat pump compressor motors help diagnose why the motor may hesitage, be slow starting, or may continue to burn out the starting capacitor.

This air conditioning repair article series explains procedures for the diagnosis and repair of hard-starting air conditioning compressors.

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FAQs on A/C Compressor Hard Start or Intermittent Run or Stutter

Photograph of  This new compressor was placed directly against
a brick wall. One third of its condenser coil cooling ability was blocked.These questions and answers about HVAC compressor motors that have trouble starting were posted originally at HARD STARTING COMPRESSOR MOTORS

Photo: a motor starting capacitor, a common repair effort for hard starting AC compressor motors. [Click to enlarge any image]

On 2017-07-20 by (mod) repairmen changed out the capacitor but two days later the AC stops working


A service tech changes of the capacitor as an inexpensive effort to get a compressor unit running.

However if the motor has essentially failed it will simply blow out replacement capacitor.

So I suspect that the compressor motor in yr unit is overheating or seizing or otherwise failing.

Your service tech can testing confirm this for example by measuring the current draw in amps when the compressor tries to start.

On 2017-07-20 by Heather

We have had two repair men out from different companies in less then a month and both changed out the capacitor and then two days ago the unit blows cold air for maybe 2 mins and then stops completely then does it again 15 mins or so later. Any ideas?

On 2017-07-19 by Doc


On 2017-07-19 by (mod) Roof Top RV AC DUO THERM used to run but now won't

Look first for a bad capillary tube or thermostatic expansion valve.

On 2017-07-19 by Doc

A Roof Top RV AC DUO THERM unit was given to me.Guess unit is about 25 years old.Used to work when removed from last RV. There are 3 speeds for fan that work. 3 speeds for AC.If switch is put on AC the compressor kicks on runs for about 5 minutes,

Pipes are getting hot and cold then you hear presser building up compressor slow down and stop trying to start fan compressor thumps and jumps around before thermal shut down.

30 seconds go by and fan will run air is cool, but not cold. then it will run for 15 min. before starting agian. I have put a new hard start compasitour on unit.

On 2017-06-06 10:55:00.318961 by (mod) repaired fan but now compressor and fan won't start


I can't say, but I'd start by tracing power to the fan and to the compressor.
All switches are on, right?

It's not an FPE Stab-Lok or Bulldog PUshmatic electrical panel powering the equipment, right?
You didn't short a control board, right?

On 2017-06-06 by Justin

Inside fan on my240volt air-conditioning went bad. I changed it,n put new plug. now the compressor n fan won't start. What did I do wrong

On 2017-05-29 by (mod) AC compressor takes 10-15 minutes to start


What are the symptoms? If they are the symptoms described in the article above then that's the best to diagnosis of your compressor problem.

On 2017-05-29 by Ankit Patel

Why My split ac is taking 10 to 15 min to start Plz help

On 2017-05-11 by (mod) re: compressor has blown 4 capacitors in a year

I would try looking for an excessive current draw or an intermittent short such as a winding short when a motor is spinning.

On 2017-05-10 by Scott

3 ton straight ac,fixed orifice. The unit has blown 4 capacitors in 1 year. Both sides of the dual run capacitor read zero with no leaks or puffing out. I cant see a strart relay and none is indicated by the schematic. The unit runs strong untill it repeatedly blows the capacitor.

On 2017-04-09 by (mod)


Several problems can cause the quick-off A/C compressor problem you describe, such as
- a failing control relay or circuit board
- a seized compressor motor
- a compressor trying to start against high head pressure due to a stuck or failed thermostatic expansion valve TEV or cap tube

On 2017-04-09 by (mod) ac compressor comes on for like 3 seconds then shuts off


If this is a new problem that is occurring on a window AC system that's been in service for some time then I suspect the compressor motor is having trouble starting - it may be failing; the unit could be repairable if the problem is only the need for a new start/run capacitor but I'm not optimistic

On 2017-04-09 by James

My ac compressor comes on for like 3 seconds then shuts off ? Any advise will be thankfull

On 2017-04-09 by Rahul

When I start my window AC the voltage of my house gets low

On 2016-07-21 by (mod) Trane BTB 718A 1984 compressor diagnosis


The unit may have other internal safety controls that shut it down due to overheating, abnormal gas pressures, or another malfunction; your service tech will check those controls.

Try cooling down the system with a garden hose to see if that makes a difference.

On 2016-07-20 by Ted ABQ

MODEL#: BTB 718A 100A1
Manufacture Date: 7/84

This hard-working unit is located at our apartment in Albuquerque, NM.

For the second consecutive day, the compressor and fan for this unit simply shut off between 4-5P.

The 2 30-AMP circuit breakers for this unit were NOT tripped. I am able to restart the A/C by resetting the two circuit breakers, which starts up both fan and compressor, which then run normally in accordance to thermostat settings.

These are the first occurrences of this condition since we started renting this unit on November, 2014. In your opinion, what is the probable cause for this unit shutting off in the middle of the afternoon?

On 2016-07-02 23:48:05.357085 by (mod) still having compressor problems after added a capacitor

sounds like a failing compressor.

On 2016-07-01 by Stephanie Evans

Fan outside and I side is blowing put start up capita tor on and still having problems with the compressor kicking on.

When it finally kicks on with the help of the garden hose it will run for hours and then kick off and about 20 minutes later it start the process all 9ver again. By the way it's Lennox. I do here the compressor string to start.

On 2016-06-18 by 1stgma

My compressor sounds like it's trying to start but then stops and never comes on fulli?

On 2016-06-17 by (mod) over-sized compressor not only wastes energy, but it won't dehumidify the home

An over-sized compressor not only wastes energy, but it won't dehumidify the home adequately as it'll cool down too fast.

On 2016-06-17 by Dd

You bring up the main issue really! Our unit is indeed to big for our home and it has caused us $$$$ over the past 6 years.

When sitting at closing our builder off handedly said, " they delivered the wrong Ac unit to your's bigger and better for the same amount" something to that affect.
How were we to know.

A year later he up sized all the duc work in the house because of issues with the house not cooling...thought all was well but at that point we were on our own.
Many hvac techs later and they all suggest we buy a brand new smaller unit at around 5k....

On 2016-06-17 by (mod) As soon as the house reaches just 1 deg below temp setting the Ac will kick back on and flip the breaker

If the compressor itself is working normally and is the properly-sized unit for the home then indeed what you describe suggests a problem elsewhere. I'd give your service manager a call and ask for diagnostic help from their senior, very experienced technician.

Wacth out: while one-step over-fusing on AC compressor circuits is usually permitted (check the data tag on your unit), upping from 15 to 40A is improper, unsafe, indicates lack of expertise and worst, is just asking for a house fire.

Your tech will probably check the thermostat settings, wiring, controls, and relays in the system. Indeed the suggestion of some of your comments is that the compressor is trying to re-start too soon and is trying to start against a high head pressure: a condition thats a problem for many compressor units.

Something as simple as a sticking TEV (themostatic expansion valve) can cause failure of the head pressure to drop after the compressor shuts off.

On 2016-06-17 by DD


Long issue time issue with our hvac! Doing the same old thing for 6 solution but told to just buy a new unit$

Had the compressor replaced last year$$$$ (unit is only 6 years house). Same issue that caused the first compressor to fail is still present.

Unit will kick on and cool home just fine. It will reach the desired temp then cycle off. As soon as the house reaches just 1* below temp setting the Ac will kick back on and flip the breaker:/ it does have a 5 min start delay but this doesn't seem to help:/ form the breaker flipping

We had the breaker fused uped to a 40amp from a 25amp last year...but it didn't help.

I have figured out that if I run and set the thermostats up 10* after the Ac kicks off from cooling the house...the Ac doesn't kick on after the 1* and give my Ac time to rest....a few hours it will not trip the breaker.

This method works every time.
This is my life everyday...babysitting the Ac :/

On 2016-06-16 by (mod) our compressor will cut off and start right up and then cut off and start right up

This sounds like a control or wiring problem, possibly a bad sensor or relay. I'd get it fixed lest you damage the compressor.

On 2016-06-16 by Donna

we have notice that our air compressor will cut off and start right up and then cut off and start right up. It seems like it does it the longer it runs. We have had coolant added and we have replaced our inside thermostat. However we are still having the same problem . What should we try next?

On 2016-04-02 by Anonymous

noisy start up

On 2016-03-28 by (mod)


Click to enlarge any image to see a sharper, bigger version. We use small image files to speed page loads for mobile readers

On 2016-03-28 by om ji

Bad photo

On 2016-03-10 by krkotrdwararao


On 2015-12-25 by (mod) Sunbeam portable AC wiring diagram


As I don't have that specific diagram try going right to b the Sunbeam service center at Sunbeam .com as they offer manuals for their products. Let me know how that works for you.

On 2015-12-24 by Nicki

Can i please have a picture of the wire connections to the compressor of a portable aircon. Make is sunbeam. Model nr spa1000. Thanx

On 2015-09-02 by (mod) if the compressor does not run the system won't produce cool air


Indeed if the compressor does not run the system won't produce cool air. The problem could be a failed compressor motor (expensive) or perhaps a bad control or relay. You'll need to call your A/C service company for diagnosis and repair.

Some diagnostics for an A/.C comporessor that won't start at all are found at AIR CONDITIONER WON'T START

On 2015-09-02 by Ingrid

Yes hi, I have a carrier heat pump. When turning on the AC the out side unit fan comes on but the compressor does not. the compressor tries to kick on but then quits. The air blowing out of the vents isnt cold

On 2015-07-29 by (mod) water cooled compressor to start and then shut off on high head pressure immediately

Perhaps a stuck or failed reed valve in the compressor.

On 2015-07-28 16:18:23.984145 by jim

what would cause a water cooled compressor to start and than shut off on high head pressure immediately with no type off water control valve

On 2015-07-17 by (mod) the condensing coil did have a leak, the system had zero coolant

Sounds like multiple problems:

1. a refrigerant leak that needs to be found and fixed
2. needing a proper refrigerant charge
3. need to repair or replace burned, damaged electrical components: not just wires but possibly relays, control boards, whatever is damaged and leading to overcurrent that burns up the wire.

On 2015-07-14 by Chris N

Just to clarify, the condensing coil did have a leak, the system had zero coolant, and the yellow wire between the relay switch and going into the unit bundle (not yellow between the capacitor and relay) was fried and appeared to have melted the brown wire between the capacitor and unit bundle.

Does this mean there is problem with the capacitor or since its the yellow wire is there possibly an issue with the condenser itself, or even would this have been a result of some other malfunctioning issue with the unit??? Your help is greatly appreciated!

I have an external a/c unit that had lost total cooling function (presumably from a leak in the condensing coil), but on inspection of the outside unit we found a yellow wire that was charred and sparking. It was not directly connected to the capacitor but we are trying to consider what could be the culprit. Any thoughts?

Question: Could Loose Electrical Wiring (or a bad A/C start relay) Explain a Hard-Starting Air Conditioner or Heat Pump Compressor Motor?

I had a tech come out and install a hard-start kit to keep a 4-year-old 3-1/2 ton Carrier compressor from tripping the circuit breaker. The compressor failed this summer. A second tech was suspicious that a compressor less than five years old would be tripping the breaker.

He discovered a loose connection in the cut-out switch. Would the hard-start kit have been necessary had the loose connection been tightened prior to it's installation? I'm wondering if the failure could have been avoided with proper diagnosis by the first tech

In 2009 tech # one had come to respond to my problem of a 4-year-old compressor kicking the circuit breaker. Without even looking at the connections in the shut-off box adjacent to the unit, he went straight into control panel, checked compressor current draw at start-up and installed a hard-start kit

. I thought it odd that a compressor less than five years old would be drawing too much current. Had no problems in 2010 but last month the circuit breaker started kicking off again late in the day.

Tech #one returned, checked coolant pressures and return temp, added some freon and started to pack up. I asked if he wasn't going to check the current draws.

He reluctantly removed the control cover, checked draw and voltages and pronounced the unit was running perfectly before leaving with my $168 check.

When the circuit breaker kicked off again the next day, I started to suspect the breaker might be worn out. Called an electrician a few days later.

He replaced the breaker switch, again without checking the connections at the shut-off box, and within eight hours my compressor had died - coils shorted to ground - confirmed by tech # one who quoted me a price to replace the unit.

Now I called a contractor I knew asking if he knew any good AC techs. He referred me to tech # 2 who, in my first call, was immediately suspicious that my original problem may have been in the wiring, not the unit. His reasoning was that a compressor less than 5 years old shouldn't have been giving me problems to begin with.

He came over to confirm my compressor was shorted out. He then did what no other tech had done since I owned the house - popped the cover off the shut-off box and tightened the leads at the terminals - black wire loose, white wire "very loose."

My question is whether that may have been my problem all along and would a hard-start kit have temporarily relieved the symptom -tripped circuit breaker- without curing the problem.


Tx Red: you and your second HVACR Tech have come across a useful diagnostic step: check for loose, or even burnt or arced wiring connections. I can't be sure of the answer to your question, as time has passed and we can't know for sure what conditions the first tech saw. A bad relay can cause compressor start problems, and I pose that its possible that arced, burned, or loose connections at the relay could make it misbehave.

Your thesis that a loose wire could have been misdiagnosed as a hard-starting A/C or heat pump compressor motor is reasonable but not, IMHO, absolutely proven by events.

A compressor start relay (or most other switches) that are loosely wired will typically experience arcing at the loose connection (an event that can, by the way, when the circuit is active or the switch closed, draw higher amps than normal due to the resistance at the point of arcing and corrosion.)

Adding a start-capacitor is adding a device that gives a big voltage surge just during motor start-up.

A voltage surge that normally is overcoming inertia in a still motor might also overcome a start relay contactor resistance, caused by damaged or burned connecting points, or by a loose connection that was in effect acting in that same fashion.

The start capacitor is delivering voltage and pushing the motor into rotation.

So without being an E.E. but with some experience around this topic, my reply is "could be" but not that we can say for sure.

Also FYI even a brand new A/C compressor could become hard-starting due to other system problems that cause internal damage to the device or even by (perhaps less likely) a manufacturing defect, events at the property, even general power delivery conditions such as abnormally low voltage. To research the topic you'd look for events that can damage the start winding on an electric motor.

Finally, it's not a surprise that the first tech didn't check nor re-check for loose wiring but I agree it would have been a useful step. Often service techs, contractors, and some investigators become habituated to a short cut of trying the "fix" that usually works successfully and fast.

IF the original start relay or contacts that were found to have been loose is still installed, one could investigate further by inspecting that device for evidence of arc burning or damage.

Question: how often to replace the hard start capacitor kit?

(May 24, 2014) Rich said:
How often should Hard Start kit be replaced? What is contained in such a kit? What is an estimated cost of the kit?


Rich: in my opinion, once. If the kit is not working then the compressor motor probably needs replacement. An exception might be if a power surge or other electrical or mechanical event damaged the capacitor.

A hard start capacitor kit should not have to be regularly replaced on HVAC equipment. If the capacitor keeps failing I suspect a wiring error or a motor that is failing solid and needs replacement.

Question: how do I fix my AC if I can't afford service

(May 27, 2014) Kevin Bresee said:
I have a Rheem 2ton central air unit. My dog months ago ate wires outside and blew the board, thermostat, and some fuses.

I had all fixed accept I just got a new thermostat and checked wiring and my problem is that the heater had worked but now that its hot the AC turns on all systems go but then it keeps shutting off and the new board is suppose to have a diagnostic light but tells me nothing.

Cold air comes out of registers, a little slower, I can see the blower motor spinning in unit/air handler and outside compressor is spinning and staying on even when the blower motor shuts off.

I looked at the only capacitor inside where blower motor is and it is not swollen or anything but unable to check voltage. Please help 98+ temps lately and cant afford service!


A homeowner can perform basic maintenance and checks to keep an AC or heat pump system working, such as checking and replacing dirty air filters. A homeowner with more skill can check that power is being delivered to the equipment.

Question: condenser fan keeps running all the time

July 3, 2014) Boyd said:
my condenser fan runs all the time and i noticed it plows cool air, why would my unit not be warming up



If you're looking for heat from a heat pump check that the thermostat has been set to heating mode.

If the condenser fan NEVER turns off then I suspect a relay or control board failure.


Question: voltage problems with an LG 1.5 5 star AC

24 May 2015 Deepak Kumar said:
I am using LG 1.5 5 star AC from past 6 years recently we are facing some problem related to voltage. AC is working fine.

Whenever I switch on the ac in between 9pm to 11pm the voltage will fluctuate, after 11 pm it will work like charm. fluctuate means the outdoor unit will be running and their is no cool air is coming from ac. I need to restart the ac. Its been 3 months I am facing this issue. If I turn on the ac after 11 PM then their is no problem. Kindly suggest what I can do?

Thanks in advance.




A problem with an electric motor (such as your AC compressor) might cause high current draw but I would not expect it to affect voltage.

Voltage is determined by your electrical supplier. I suggest starting by asking an electrician to check the incoming voltage at your electrical service, or perhaps to mount a monitoring device there.

Keep us informed and we'll take it from there.

Question: Haier 1.5 ton split ac after switching on it blows cool air for 10 minutes

26 May 2015 podeswar said:

i am having Haier 1.5 ton split ac after switching on it blows cool air for 10 minutes n then it blows hot air the complaint is not retifaing loaded gas changed coil changed condencer but the problem is not rectifaied the compressure is getting over heated


Start by checking for cooling coil icing. See COOLING COIL ICING or LEAKS

On 2012-09-27 17:46:34.484127 by Jesgrate

Rheem condensor only runs for 1/2-2 hours at a time and then quits. Have had a/c tech out several times.

Replaced breaker, changed wiring in thermostat, reconnected loose wire at furnace. Still not corrected. Could it be the thermostat? Unit is about 10 years old. Tech wants to come back and check 2400 ohms at furnace to same at condensor.

States if not same have to either replace wire in wall or I have a bad control board. Does this sound right?

On 2012-09-16 18:43:18.401039 by (mod) -


The refrigerant pressure behavior you describe sounds normal - normal pressures being developed when running and normal equalization when off.

I'm not sure the compressor is really OK - I'd suspect a control board except you report that the compressor motor gets abnormally hot. See ELECTRIC MOTOR DIAGNOSIS tests for details that explain that testing an electric motor (like a compressor) when it is not running are helpful but incomplete.

Or perhaps check the maunfacturer's specs on operating temperatures for the compressor and compare those to what you are actually seeing. Keep us posted - what you find may permit more comment and will also help others.

On 2012-09-15 23:28:23.728714 by Anonymous

Problem: AC compressor starts and runs for 30 to 45 seconds then shuts off. Compressor 220v /1 phase 2.5 ton scroll. During this time it gets very hot..then cools off and would restart again to run for only 30 or so seconds. Fairly new compressor less than a year old.

Checks already done: All start and run capacitors checked and are good./

Compressor windings checked across all three terminals and ohm out good./ Potential relay is checked and cuts it out of circuit as designed with amp meter./ Voltage is good. / When guages are attached to high and low side and the compressor starts the pressures move as designed both high and low.

When it shuts off they equalize. In other words no high head pessure etc.
Question: Could the internal heat overload protection be faulty...i have rarely seen this.

On 2012-09-09 21:02:31.923944 by jayvan

b4 u mention about ur aircon problem u should diagnose carefully check all electrical coponent b4 u give the cause of the problem sometimes the problem coming from the tech w/wrong diagnose of the units make it sure that u should check it all one by one thanks

On 2012-09-06 22:07:02.240081 by (mod) -

Jack, often a humming and delayed start means that there is a bad start/run capacitor or a bad motor. I'm not certaint that your capacitor test was complete (though it was a good idea) - for example if a motor is hard starting and a cap defective, it may seem fine when mounted at another motor that is not hard starting.

There are some compressor measurements & tests that look for an open winding or a dead short as well as for high amps current draw during startup - I'd check those. WATCH OUT for electrocution hazards - if you're not trained and equipped be sure to ask for expert help.

On 2012-09-05 15:51:28.416149 by Jack

Also checked breaker and relay, they are also good.

On 2012-09-05 15:12:32.331009 by Jack

My compressor fan works fine but when the unit is switched on the compressor makes a loud hum for about 2 seconds without starting and conitnues to repeat the hum about every 7 seconds.

I think the compressor is locked up but not sure. The capacitor is good (tried it on another unit). Also did ohm test and it checked out fine. What else can I do to trouble shoot it before I replace it?

On 2012-09-02 19:09:13.078122 by Anonymous

After my central air conditioner works a long time to get to the set temperature, when it shits off and then restarts when temperature rises the circuit breaker pops

I had a booster installed but did not help. So this week I installed a super booster but it started the fan but not the compressor. So I shut off the system for two hours and the compressor worked fine. Now over the weekend I kept the thermostat on 74 so it did not have to work too long at a time and it worked fine.

My question is what could be the problem and how can I repair it?

On 2012-09-02 13:36:28.055626 by Paul P

When the A/C unit attempts to start, the blower fan on the Compressor Unit starts but you can hear a Surge of Power that dims the lights and you can hear at the surge at the power panel but the compressor hasn't started. There may be as many as 5 or 6 surges with 10-15 second pauses between them and then the compressor kicks in.

Our A/C Tech checked the system and said it's numbers are all with in the limits of normal operation .
The Surge Of Power trying to start the compressor can't be normal. Not only am I concerned with the A/C Compressor damage but my power bill with all the surges.
Any suggestions welcome..

On 2012-08-26 11:17:49.199753 by jose

What amp breaker do you use for à 4 ton ac unit?

On 2012-08-11 18:05:55.593301 by Chuck


On 2012-08-11 02:03:46.454671 by (mod) -

You could be seeing a voltage drop across the wire - usually the electrician looks at the anticipated current draw or circuit amapacity requirement and the length of wire run and finds the NEC table that suggests at what length to go to a larger wire size. I'd also suggest a very careful check of the connections themselves. For example a corroded aluminum wire connection could be trouble.

On 2012-08-10 17:46:20.908957 by Chuck

Question about a long run. We have a 5 ton unit (8 years old). Bought the house from the builder. Unit is regularly serviced, but it has always had starting pull that you can "feel" in the house. The unit has a hard start capacitor, which appears to be working.

The electrical run to the unit is long, however. It's about 80' from the breaker to the unit. I'm wondering if a larger wire may help the start? Curious about my options! The "buzz" and dim lights when the unit starts (again, did this from day 1) would be nice to solve! Appreciate the time you all take to answer questions like this.

On 2012-07-27 19:50:41.621977 by (mod) -


Regarding "how long can the unit stay on trying to reach set temp" the answer is ... it depends. It depends on quite a few variables such as

- the outside temperature
- the inside temperature
- the rate of heat gain of the building, sun exposure, weather, direction orientation of walls
- the SET temperature of the thermostat
- the capacity, design, of the cooling system
- the cleanliness of the air filter
- the presence or absence of duct defects such as crimps, or crushed ductwork or air leak

Since some of these variables are different from hour to hour and day to day - weather - and others vary by human action - thermostat settings - we can't expect there to be a standard number of minutes or hours that a cooling system will stay "on" trying to reach the set temperature. In fact if we make the set temperature low enough the cooling system will run forever without reaching it.

A more helpful question to ask is: does your system seem to be working differently than it used to - taking weather changes into consideration? and is there good air flow at supply registers and is that air cool?

On 2012-07-26 21:38:38.523691 by Cristie

I did slightly bend a few cooling fins but I fixed them back to normal but what else I need to know is b4 I cleaned dust off the evp , could dust have gotten sucked through cooling fins and clogged something? I know the outside drain hole isn't plugged up so maybe some other area?

I know it ran great a yr ago new with 95+ degrees outside & now it doesn't get as cool as it should and my MAIN question was/is how long can the unit stay on trying to reach set temp I remember it cycled more frequent than before I cleaned evp... I don't want to blow my window unit ..any help, PLEASE

On 2012-07-25 23:08:19.139231 by Anonymous

Christie the equipment should be able to run as you describe.

And while there may be more to your question than was evident, if dust was removed from the evaporator coil that's good, helpful, and not harmful - let's hope no one bent or crushed the cooling fins.

On 2012-07-25 22:04:12.422061 by Cristie

Will dust covering the evp coils but then sucked out cause a problem fo the window unit?

On 2012-07-25 04:37:07.122445 by Cristie

Is it ok for my window unit to run with cold air without taking a break even though the desired temp isn't reached.

When I first bought unit it seemed to cycle off & on and now when on coldest setting it isn't cutting off is this going to break the unit does it have to cut off (the compressor) I guess or is it ok to keep running hours or until desired temp is achieved please tell me

On 2012-07-14 19:23:14.740328 by Roland

Thank you!!!! You saved me a lot of trouble and expense with your article on the capacitors and all the other excellent information

Thanks again

On 2012-07-08 19:58:35.444812 by Charles

Outdoor A/C unit. Temps in the high 90's. Found compressor running, but fan stopped.

Found badly corroded connection between condenser fan and capacitor. Female connector was burned and barely in contact. Wire charred for about 1/2" at connector. Removed burned end of wire, scraped the copper, replaced connector. Unit ran normally until the next day.

Now starts normally, but 20 to 30 minutes later,the condenser fan shuts off. Feels hot from mounting point. Compressor still running. Shut system off for 30 minutes. Repeat, unit starts normally etc. When running, the inlet line is cold and dews normally.

Cleaned all contacts on capacitor. No change. Fan runs until the case temperature is around 130 degrees, then shuts down. Fan case temperature then climbs to 146 degrees before beginning to cool.

Tried to check capacitor. In checking resistance, got no reading. Then put voltmeter across terminals and registered a declining voltage. Capacitor MAY be okay.

Checked voltage. Ran 240V from T1 to T2, 108 to 112V from capacitor to T2.

Still not sure what the problem is, but starting to suspect the fan a bit more.

On 2012-07-01 17:56:04.017847 by Anonymous

if compressor and the fan motor do not come on what can be the problem


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