Our air conditioner recently stopped blowing out cold air. When I went to check on it, I noticed that the outside unit wasn't coming on. We had had problems with ants in the contacter in the past, and so I went to take off the lid and check it out. I noticed that the circuit breaker marked "AC" was tripped. Like a good DIYer, I turned it all the way off and back on. It immediately tripped again. In an effort to isolate the problem, I went to the outside unit and pulled the safety connection to disconnect the main power of the outside unit. When I went back and reset the circuit breaker as before, the breaker didn't trip. Reconnecting the outside safety switch caused the breaker to immediately trip again. Later, we tried turning off the air conditioning in the house, resetting the circuit breaker, and turning the AC back on. The circuit breaker didn't trip as soon as it was reset, but when the AC was turned back on inside, it immediately tripped as before. My question is what should I check in this situation?

This seems like it can't be an uncommon problem, so I'm sure HVAC professionals encounter this frequently and have a checklist of things to try. What are the possible causes, remedies, and safety precautions I should consider in this situation? Answers to some comments: No, I didn't see any obvious damage to the wiring near the outside unit. I did look pretty carefully, since I had already taken the panel off to check for ants in the contacter. I didn't try to spin the fan with my hand, and I'm not in a place that I can try this right now. I will try it later today; perhaps in the meantime that could be a step in the diagnosis of the problem if anyone gives an answer between now and then? Likely, future readers of this question will encounter the same problem and some will have a fan that spins by hand and some will have one that is stuck. electrical repair hvac air-conditioning circuit-breaker Start by turning off the breaker, and pulling the serviceman disconnect, which will typically look something like this.

This will insure no electricity is flowing to the condenser unit while you're working. Next you'll want to disassemble the unit, to allow access to the electrical parts. This will vary from unit to unit, so check the owners manual for the procedure for your unit. Once you have the unit opened up, make sure to discharge the capacitors. These things store enough power to kill you, so you don't want them to discharge accidentally. Resistance is not futile Once the power is completely removed from the unit, it's safe to start poking around (electrically speaking, don't go busting the refrigerant lines). Start by tracing the wires from the condenser fan motor, back to where they connect in the electrical box. There should be 3 or 4 wires. In my unit, I had Black, White, Brown, and Brown with a White stripe (your model may vary). To determine if the motor is good, you'll measure the resistance across each coil. To do this, you'll have to disconnect the wires, so the motor is no longer part of the circuit (make note of where the wires connected).

Typically you'll have 3 wires, start, run, and common (we'll ignore my 4th wire in this answer). Set your multimeter to measure Ohms, and start measuring. You're going to measure the resistance between each combination of two wires to determine what each wire is, and if the motor is still good. ac unit waterLet's start with Black and White...cheap ac units uk Black -> White = 15.9no window ac units Black -> Brown = 35.4 Brown -> White = 51.2 Common -> Run = Lowest resistance Common -> Start = Medium resistance Start -> Run = Highest resistance We can determine that... If we also know that the two lower readings should always add up to the larger reading, we can safely say this motor is still good. If you measure 0 or infinity between any pair, that means you have a shorted or an open winding and the motor should be replaced.

Repeat the same procedure for the compressor motor. Shorts on the ground The other thing you'll want to check for, is shorts to ground. Set your multimeter up to test impedance. Put one probe on the equipment grounding conductor of the feeder, and the use the other to find a solid ground on the motor. You may have to scratch some of the paint off, especially on the compressor. Once you've found a solid ground, measure from each motor wire to your ground spot. If the meter beeps or give a low resistance reading, you have a short to ground. As with the resistance test above, the motor should be isolated from the circuit when doing this test (once a solid ground is located).Browse other questions tagged electrical repair hvac air-conditioning circuit-breaker or ask your own question. 2 posts, read 9,781 times Carrier Unit in a 1600 sq ft House built in 2003. The outside fan, When running Heater, turns on and off in 5 second intervals, over and over again. The unit does in fact blow hot air!

Although when running AC, the outside fan runs continuously. After turning breaker off, and removing outside Fuse, I Checked the outside unit, removed the fan and fuse casing area. In there, I was able to see (what I believe it to be) the fan relay switch. When I turned breaker/Heater back on, I could see this switch triggering every 5 seconds as the unit was turning off and on. Which you could hold down to bypass it from turning off! I do have a small freon leak, Had to recharge a few pounds last summer. I know I should leave this for the professionals but my wife is 9 months pregnant and We don't have too much money to work with. I hope someone can give me some pointers. Let me know if you need more info, And thank you for your time! PS. this is my first thread so I do apologize if it isn't forum-al! 5,105 posts, read 5,676,513 timesYORK, Pa.-- With high temperatures over the next few days, now is not the time to have your air conditioning unit fail you.

"The biggest thing that people can do right now to help their air conditioning system is [to] check the air filters," F.W. Behler Inc. President Dave Yates said. F.W. Behler is an air conditioning company in York. Yates said dirty filters are one of the biggest problems he sees each year. He also recommends to wash the outdoor coils of your unit. Simply take a garden hose and wash them from the top to bottom. "That dirt that's out on those outdoor coils can rob that system by as much as 10 percent or more efficiency and reduce the cooling capacity," he said. Then there is using your air conditioner efficiently. You can close up to 15 percent of the registers in your home to make it easier on you air-conditioning unit. "So the idea is to find one area where you can totally comfortable and those unused rooms, it doesn't matter if they get comfortable," Yates said. Yates recommends setting your thermostat to one temperature and leaving it there. He said to turn off any set-backs your system may have.

"To make it back from 82 to 78, or 76, or 74 degrees is not going to be a quick result," Yates said. "It can take a day or more for that to happen." Even with these tips, Yates is expecting numerous calls for problems, and he said his crew are ready to tackle the challenge. "We'll ask everybody who works here to be available for the on-call guy so that when we do hit a peak of emergency calls, we can respond and get those done in a timely fashion," Yates said. Yates posted a full list of tips on his Facebook page. 1: Install new air filter(s). Insufficient air-flow reduces the delivery of cooling and can shorten the life of your equipment! 2: Clean the condenser (outdoor unit) coils. Turn off the power first to the outdoor unit. Set your garden hose to spray, not full-force nozzle, and wet the coils working from top to bottom. If you have a hand-pump sprayer, fill it with water and dish detergent & spray that into the coils – again working from top to bottom.

Rinse away with the hose spray. Dirty outdoor coils that “look” clean can rob you of 10%, or more, efficiency and reduce cooling capacity. 3: Let the condenser breathe! Trim back shrubs or bushes at least 24”. FYI: your condenser coil should be a minimum of 18” away from the wall. This allows for proper air-flow across the condenser coils to strip away heat from the Freon inside the coils. 4: Shade the condenser. If your condenser is baking in the hot sun, provide it with shade by setting up a beach umbrella, but do not place the umbrella directly over the top of the condenser because that’s the discharge for hot air from the condenser fan. There should be no air-flow obstructions within 5’ overhead of the condenser. 5: Make sure your windows and doors are closed securely. Replace worn weather stripping. 6: Grill outdoors – no indoor cooking. 7: Turn off incandescent lighting. A 100-watt light bulb produces as much heat as one human body at rest (341-Btuh).