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My A/C is having problems for the last few days. My outside unit which the main motor is always cycling off and on every 3-5 minutes and the room temperature is not improving.

This happens even when the inside fan is working just fine. However, the problem starts when the A/C is turned on, it doesn't matter if the room is cool or not.

Kindly please assist me. Thanks.

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    Air Conditioning is not normally a DIY project unless you have some advanced skills and the tools. I would recommend you call a reliable A/C service technician.
    – ArchonOSX
    Sep 30, 2017 at 8:14
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    Your reference to the main motor, whatever that is, tells me that you need to call an HVAC service tech and keep yourself safe.
    – d.george
    Sep 30, 2017 at 10:09
  • Something easy you can do is check the batteries in your thermostat (assuming it has batteries). As others have said here, FIXING it would require a tech if the problem isnt thermostat control related.
    – noybman
    Sep 30, 2017 at 14:13
  • One easy check is the overflow pan in the attic unit. Sometimes there's a float switch so that if its full of water the outside unit will not work. Happens to me from time to time. I agree with these guys, look for the obvious then call a pro.
    – Trout
    Oct 3, 2017 at 19:17
  • I see this on older units that are low on Freon. The thermal safetys protect the compressor. Turn system on it overheats and shuts down cools off and restarts, get a HVAC licensed person to check it out before damage is done, many times on an older system a recharge will bring the system back to life for a few more years.
    – Ed Beal
    Feb 14, 2018 at 14:13

3 Answers 3

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If the condenser cycles every few minutes (likely due to an overheating motor) it's probably one of two things.

  • Compressor is shot (not user serviceable)

  • Fan motor is shot (user serviceable)

If the whole thing outside shuts down, it's the compressor. If it keeps making noise but the fan outside isn't running, it's the fan. Do not run it or let it keep cycling for extended periods in that condition.

Jumper the thermostat leads at the condenser to eliminate the possibility of wiring and thermostat problems.

If it's the fan, take the motor out and bring it to a parts store after your get the blade off of it (if you can't get the blade off buy one of those too). If it's the compressor you're out of luck.

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    Even bad compressors can be replaced but a low Freon level , or bad starting cap is much more likely to be the problem.
    – Ed Beal
    Dec 1, 2018 at 17:17
  • @EdBeal +1 for bad starting cap, I would check that before blindly replacing fan as mentioned in this answer.
    – Glen Yates
    Aug 18, 2021 at 22:20
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Are you getting ANY cool air coming out of your vents or condensation drainage from the A/C drain pipe by your inside A/C unit? A good rule of thumb I've used for residential A/C is to have about a 15-20 degree drop between room temperature and air coming from the A/C.

A few suggestions to check before calling an trustworthy A/C repair service person:

  • Check to make sure you don't have a utility mizer device hooked up to your A/C that cycles the power based on a signal from your utility company. If you do, you can contact them to make sure you don't have a problem that's causing the outside unit to cut in and out based on a faulty signal from your electric utility.
  • Check/change your inside air filter to make sure it's not blocked with dust/debris that's limiting airflow.
  • Check your outside unit to make sure the coils are clean and aren't being blocked. If your coils look quite dusty/dirty, take a hose and spray out the dust and dirt. DO NOT use a pressure washer as that puts too much force onto the aluminum fins and will cause them to bend and become less efficient in transferring heat away.

But, as others have suggested based on your comment about the outside compressor turning on and off every 3-5 minutes or so, it sounds like something that needs a professional to look at as the most likely scenario would be a coolant leak, which requires a professional to diagnose and repair.

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I have a feeling this came up because of the high humidity. I am assuming you do not have HVAC (Heating Ventilation & Air Conditioning) experience. First check the condenser, that is the part on the outside that gets hot, there should be free air flow through it and it should be clean, not clogged with dirt. Be sure the fan is operating properly. Also check the evaporator (the part that gets cold), if it is a window unit remove the cover and see if it is full of ice, if so just let the fan run until thoroughly dried. Check if it is clean, and if not get the crud out of it but be careful and change the filter. If it is in your furnace, check the filter and probably replace it unless it is nice and clean. See if you are getting plenty of air out of the ducts, if not you probably have iced the coil, turn the AC off and the Fan on for about an hour, see if the air flow improves. If so try turning the AC on and if that solves it great. If not call a service tech. Postponing getting the tech can allow additional damage to the unit, depending on the problem.

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