Bad Contactor On Outside Unit

It is 24V DC you need to check. Is your air conditioner leaking water inside or outside your house or business? Excessive condensation from air conditioning is a sign you have an ac issue. Contactors usually need to be changed every 5 years under normal operation. Rinse the coil cleaner off with the hose. Recommended purchase. Checked electrical. Description: This is the procedure and information for replacing a contactor on an air conditioner. If you have that voltage at the contactor, it is likely that the contactor is bad since you are able to push the contactor in manually and it will start the unit. Be sure to shut off power to a unit before examining any components on an air conditioning unit. Lets take a moment to see what exactly is inside the condenser (that's an outside unit) You have a compressor, a fan and motor, a contactor, a cooling coil, and a capacitor. You could tell points were burnt. 365 day right part guaranteed return policy. I would recommend replacing that first. You mentioned that the outdoor fan operated when you manually pushed in the armature on the contactor, so your line voltage power circuit seems to be intact. B−Contactor The compressor is energized by a contactor. That's that big box outside your home, by the way. The condenser unit fan is a blower that moves outdoor air across the condensing coil found in the outdoor compressor/condenser unit. When pressing your heater or air conditioning reset button or switch allows it to turn back on, a bad contactor is likely the cause, according to HVAC For Beginners. If so get a new contactor assembly. When this closes the power supply to the house will energize the outside unit. The control board inside the air handler probably went bad. If there is 24V, the capacitors and contactor are ok, there is 240V and nonetheless the condenser fan motor would not turn, you have a wiring difficulty at 240V that desires to be corrected. We've never experienced an AC unit that breaks at a convenient time. When mounting the outdoor unit on a roof, be sure the roof will support the unit's weight. 852 thoughts on "Common Air Conditioner Capacitor Failure Symptoms" if the outside unit contactor is. Carrier 1 Pole 24V 30 Amp Contactor HN51KC024. April 15, 2015. Inside your AC's outside unit, under the cabinet, you will find a tall cylinder or oval of shiny metal. Related Articles. Hung out for about another 30 minutes, started to turn off-on real quick. Make sure to kill the power to outside unit before servicing any part. Without the added power of a working capacitor, the. Checked duel capacitor and contactor. Many people have asked me "Why do Air Conditioner Capacitors Go Bad?" Capacitors typically have a life as measured in cycles. If you have control voltage at the compressor contactor coil, but the contactor does not energize, your central air conditioning condenser problem is a failed contactor. Multimeters – Measuring Resistance. In photo #3 of 5 - If you have an insulated screwdriver or are competent to find a non conductive probe of some sort*, try pushing that rectangular "button" in the center of the contactor (which is properly termed "that grey thing with all the brass, the black and white wires hooked up to the top, the orange wires hooked up to one side, the yellow. Below is a single pole contactor with a 24 Volt coil. You will have to find the contactor which is located in the outside unit. you can disconnect the high voltage and the contactor will still close. And, just like we explained earlier, this means the. Most likely the humming noise is coming from a contactor located in the outdoor unit if you hear the noise outside or from. buzzing is on the low voltage side of the contactor. Some minor problems you can fix yourself, or ask your landlord. The system will shut down. If the contactor pulls in, it's not the outdoor unit, iether low voltage wiring or start looking at the indoor unit. A/C question: My outside unit runs, but no air is being pushed through the vents in the house. The wire was connected to a capacitor. With these particular motor savers, just because there is a ‘Green light” IT DOES NOT mean its good, the green light can be on and unit is bad the way to check it is to use you meter to check the bottom control wires, if the voltage is ZERO its good, if you read voltage it is BAD, for time being the control wires can be wire nutted together to get the rack going. The contactor coil, time delay and temperature sensor are all energized by 24VAC supplied by the indoor unit. No where on my current contactor can I find the words 1 pole or the amperage. If the fan malfunctions, the coils won’t be cooled and the unit will overheat and trip the circuit breaker. I flipped the breaker back on and it instantly tripped again. Multimeters can measure the resistance in ohms (£2) of all or any part of the circuit. Contactor relay switch (a low-voltage switch in your outside unit controlled by the thermostat. If, after all of these steps, you're outside unit is still not turning on, call an AC repair company. An AC unit has several main components, including a condenser, a compressor, an evaporator and an expansion valve. Works great, even in 100 degree weather. This contactor was very simple to install; using a 5/16 nut driver, a flat bladed screwdriver, and a small pair of needle nose pliers, each contactor took 10 minutes to replace. To raise the voltage, change the tap connections on the control transformer. What is the average Labor and material cost to install an contactor and a capacitor on an AC I just had a work done on my ac Make Trane, Model#277R3048A100cA, Serial# 60828y72F They replaced 2 pole contactor 61421 MARS contactor full load AMPS 40, coil Voltage 24 VAC and a capacitor 440VAC T10000AFC DIELEKTROL VI. It may look like the contactor in the picture or it may be similar, but have a metal bar across the top. Any residential hvac guys here? Off Topic. It doesn't tell you anything a volt meter won't, and it risks your equipment if there is no charge or a leak in the system. - Buzzing contactor. There is both low voltage and high voltage going to the contactor. study guide by jukplat includes 70 questions covering vocabulary, terms and more. Recommended purchase. Your contactor is the “middleman” between the thermostat and your compressor. Contactors typically have multiple contacts, and those contacts are usually (but not always) normally-open, so that power to the load is shut off when the coil is de-energized. Here are 4 common air conditioner problems you may encounter: 1. When the thermostat calls for cooling it sends 24VAC to the contactor coil, energizing it, which turns on the outside unit (both compressor and condenser fan). A failed contactor will either keep your unit running continuously, or keep it from running at all, depending on whether the contacts were open or closed when the circuit failed. You should hear a click as the contactor inside the outside unit engages. On the outside you see the brass but underneath looks blackened. A possible sign your run capacitor has failed is that the compressor unit outside your home does not start up. Any residential hvac guys here? Off Topic. Central air conditioning parts, heating parts. This year, i had trouble with the blower motor not always coming on when the unit started up. My A/C will not run - can a bad compressor contactor cause the 24V transformer to burn out? So, my upstairs A/C unit wouldn't run. If, after all of these steps, you’re outside unit is still not turning on, call an AC repair company. To raise the voltage, change the tap connections on the control transformer. The tattle tale will tell him if the switch is the problem. I wonder if you don't have a bad contactor. study guide by jukplat includes 70 questions covering vocabulary, terms and more. Without the added power of a working capacitor, the. An AC unit has several main components, including a condenser, a compressor, an evaporator and an expansion valve. This could also be a bad contactor if the contactor coil is getting 24 volts and not closing. I've got 240v going into the contactor, but nothing on the 24v lines from the thermostat, and nothing going out of the contactor. Have home AC compressor questions?. 9) or in the outdoor unit (see Fig. Limitations This unit is designed and approved for outdoor use only. I would recommend replacing that first. I only had to clip the forks off (only the forks) off of the AC unit leads and inserted the crimped remaining end into the contactor terminals. Based on the fact that my thermostat was able to control the blower fan, I guessed the problem was caused either by tan HVAC controller unit (located in the blower fan unit) or from s failed component inside the condenser. Determining Coleman AC Furnace Parts The best way to determine what part number you need it to look for the number printed on the part itself. Since the indoor and outdoor units work in tandem, having a newer, more efficient outdoor system paired with an older, less efficient indoor system can lower the overall efficiency of the unit, cause frequent repairs and lower the unit’s lifespan. Obvious signs of failure include a gooey, leaky or bulging capacitor or a burned contactor. Air Conditioning Air Quality Outside unit clicking but won't come on? It’s likely either a bad contactor or capacitor. But sometimes all it takes to recognize a problem is a visual inspection. The heat pump and heat strip DIP switches are both set to the ON position in one zone. com has an excellent article. In this case the contactor had an open coil and was not energizing the compressor or outdoor fan motor. Any residential hvac guys here? Off Topic. Since a damaged or corroded contactor can cause the unit to run longer than it is designed to, the unit often shuts down to avoid overheating or blowing the motors. Help as to how to after you have read and watched on you tube and still confused, Quora is a good place but otherwise go to google fi. When the indoor unit stops running, the system will immediately start to freeze because there is no airflow. If the outdoor AC unit makes a buzzing sound, as though it wants to turn on but can't, the run capacitor may be defective. If the outside fan isn't running, unless it's raining on the unit, it won't be able to reject the heat and the line sets would get warmer with each second of run time. Determining Coleman AC Furnace Parts The best way to determine what part number you need it to look for the number printed on the part itself. Problem: Either no power is getting to the outdoor unit or you have a defective compressor contactor. This electricity then flows through the disconnect box to the compressor and condenser fan motor. Attics are a bad place for ducts, particularly if they are poorly insulated and long (large surface area). This year, i had trouble with the blower motor not always coming on when the unit started up. You can also push in the contactor and see if the fan and compressor start. Usually a quick fix by replacing the. How to diagnose what part of the outside A/C Unit is bad? Are these contactors the same regardless of what unit you have? I think I'd like to pick a spare up as well, but don't know if there's. You noticed that your AC is no longer blowing cold air. The very first thing that you should check is if the contactor coil can still move the contact assembly. Other signs of a bad capacitor: Bottom or top of capacitor is bulging; Visible gooey discharge on the capacitor; 2) Check your contactor. April 15, 2015. Here are 4 common air conditioner problems you may encounter: 1. Checked duel capacitor and contactor. In this case the contactor had an open coil and was not energizing the compressor or outdoor fan motor. That's that big box outside your home, by the way. Section 7 Part 2 Page 1 / 7 Date 09/07 Application Manual for NEMA Motors Thermal Protective Devices Thermostats (Klixons*) Thermostats use a snap-action, bi-metallic, disc-type switch to open or close a circuit upon. I wanted to title this: Outside unit running, but thermostat is off but I'm 99% sure its the contactor unless someone here says otherwise. It seems that ever year or so I need to replace my contactors because they have burnt out. This electricity then flows through the disconnect box to the compressor and condenser fan motor. This can leave the fan motor running. If the outside fan isn't running, unless it's raining on the unit, it won't be able to reject the heat and the line sets would get warmer with each second of run time. 3 then that's not the case. Please enable it to continue. NEMA and discussed the basics of a motor starter. It’s always a bad idea to only switch out just one unit. You probably have a loss of charge switch that's open and preventing the AC from turning on. The Capacitor and Contactor are a Team. If you have both line voltage and low voltage at the outdoor unit, it sounds like you have either an open pressure switch or a defective contactor coil. the 24v from the transformer pulls in the contactor, not the high voltage leg. Last Monday, I came into the office in the morning and the air handler was blowing air, but the A/C unit was not working, such that the A/C was blowing warm air. A bad capacitor on the outside unit for the compressor and condensing fan motor has no effect whatsoever with the indoor blower. Shop Grainger for your electrical needs today. Your compressor is the part of your AC unit that transforms the refrigerant chemicals from liquid to gas and back again in a continuous cycle, generating the cool air. The AC unit turns on but doesn’t cool. Dirt or insects can get in between the contact points while the contactor is off, and cause the air conditioner not to come on at all. From time to time, you may notice your air conditioner leaking water outside. Continue testing all the way out to the outdoor unit's contactor. running unit on spa only exists in the summer when spa temperature of about 100° F is reached and the unit shuts off with the ‘HI’ fault. (Parts located in the outdoor condensing unit section or compressor area ) Some of the Air Conditioning parts available: contactor, fan blade drain pan,kit. The outdoor fan is not designed to operate against any additional static pressure. No where on my current contactor can I find the words 1 pole or the amperage. Works great, even in 100 degree weather. How to replace a bad capacitor on the outside ac unit? My outside fan motor for my ac was humming but not spinning so i took a stick and moved it and it started. Lets take a moment to see what exactly is inside the condenser (that's an outside unit) You have a compressor, a fan and motor, a contactor, a cooling coil, and a capacitor. Dirty A/C air filter: Dust can also collect on your A/C’s air filter. It will have wire connectors leading to it. Outdoor Unit Not Running by: Dadan Hey, Bill Not changing the contactor is negligence on your local tech parts. Kung Fu Maintenance shows AC Relay Air Conditioner Contactor Not Pulling In Five Most Often Causes 1) Bad Thermostat 2) Bad Wiring 3) Bad Contactor 4) Bad Tr. Air Conditioning and Cooling Systems - How Do I Test The Contactor In Ac Unit To See If It Is Bad? - Hi again all, Have seen a lot of great questions and answers on ac in this forum. The contactor sends voltage to the condenser and outdoor fan motor. Help as to how to after you have read and watched on you tube and still confused, Quora is a good place but otherwise go to google fi. AC Not Blowing Cold Air After Power Outage. @ David Butler Lets start with what we seem to agree on. Resistance values o f HVAC components can vary greatly from a few ohms to several million ohms. Your AC evaporator coil will send the refrigerant through this line and if the Freon is low, the coils get too cold and causes a cold liquid refrigerant to flow through the line. Your contactor is the "middleman" between the thermostat and your compressor. I recently replaced both the capacitor and the contactor in one of our A/C units when it stopped blowing cold air, so I've documented the process to share with you here. When the weather turns warm the coil yanks down and you have crispy critter and no cooling either. 99% of the time a contactor chattering is the result of either debris on the armature pole faces, or a broken shading coil. Either the contactor is bad or you aren't getting power to unit is two most likely problems. My fan is not running on the outside ac unit. If there is 24V, the capacitors and contactor are ok, there is 240V and nonetheless the condenser fan motor would not turn, you have a wiring difficulty at 240V that desires to be corrected. The tattle tale will tell him if the switch is the problem. Checked duel capacitor and contactor. Wait 10-15 minutes as the cleaner foams and bonds with the dirt on the coils. Could you tell what could this possible be? Could it be the contactor gone bad or what? Please help me out this matter. Most likely the humming noise is coming from a contactor located in the outdoor unit if you hear the noise outside or from. Today we're going to talk about what an air conditioner contactor is, what can go wrong with a contactor and what you can do to prevent problems with your air conditioner's contactors! What is an air conditioner contactor? A contactor is a small device that controls the flow of electricity to one of your air conditioner's components. A contactor really has only two basic parts: the contacts and the coil. The inside unit absorbs heat from your air using refrigerant. You go outside to check the A/C unit, and it's buzzing but the fan's not spinning. Condenser air enters from three sides. But if only your outdoor unit fails, why do you usually have to replace the entire system (or vice versa)? Many clients are surprised to learn that they can't just replace the outdoor or indoor unit and call it a day. Want a quick answer for a simple question go to google! It's faster and more precise than what you will get here. Many people have asked me "Why do Air Conditioner Capacitors Go Bad?" Capacitors typically have a life as measured in cycles. An open circuit stems from the inability of the contactor to energize. QAS 150-200 Cud Portable Generator pdf manual download. It will have wire connectors leading to it. Condenser coil fan problems: The condenser coil fan is responsible for cooling your outside A/C unit's condenser coils. A bad capacitor is a common A/C problem with a straightforward fix. Many people have asked me "Why do Air Conditioner Capacitors Go Bad?" Capacitors typically have a life as measured in cycles. My A/C unit outside stopped working a few days ago but my air handler was still working. Do this with a circuit that has been power down. NEMA and discussed the basics of a motor starter. Ray Austin mentioned placement of the unit. I've got 240v going into the contactor, but nothing on the 24v lines from the thermostat, and nothing going out of the contactor. I would make certain the filter and the coils are clean. goodman parts relays. Why is My HVAC Unit Making a Loud Humming. Vibration from the unit was causing the bellows to open/close. For further assistance, please contact: WARNING To prevent the risk of property damage, personal. Contactor relay switch (a low-voltage switch in your outside unit controlled by the thermostat. Compressor wasn't starting and fan motor was just humming. Air conditioning technicians use what’s called a voltage multimeter to test for a bad capacitor and contactor. Solving the problem comes with cost variables. Air Conditioning and Cooling Systems - How Do I Test The Contactor In Ac Unit To See If It Is Bad? - Hi again all, Have seen a lot of great questions and answers on ac in this forum. Help as to how to after you have read and watched on you tube and still confused, Quora is a good place but otherwise go to google fi. That is a typical sign of a bad motor, usually it is the outside condenser motor, but could be the indoor blower motor. - Loud unit. AC compressor buzzes. Common Air Conditioner Capacitor Failure Symptoms. If not then replace the contactor and go from there. To raise the voltage, change the tap connections on the control transformer. Refer to unit wiring diagram. If the contactor has proper low voltage applied to the coil and it does not pull in, it is a bad contactor. The contactor unit 220 may already include an adhesive 250 or other securing mechanism on the second side 223 of the contactor unit 220. The cause of you AC freezing up is not enough air flow over the coils. Ray Austin mentioned placement of the unit. HVAC mechanic/plumber/gas fitter can have a cross over electrical certification that allows them to work on low voltage appliances of less than 600V. Mis-wiring in outdoor unit will cause loss of communication and operational problems in this system. If the outdoor AC unit makes a buzzing sound, as though it wants to turn on but can't, the run capacitor may be defective. Related Articles. 1 Be sure the thermostat is set properly. HVAC Troubleshooting: How to Fix Loud & Strange Noises Coming From Your AC Unit. Search Fixya bad contactor on outside unit Jul 24, 2012. Compressor Locked Rotor Diagnostic. Here are 4 common air conditioner problems you may encounter: 1. Want a quick answer for a simple question go to google! It's faster and more precise than what you will get here. Well, if the capacitor goes bad, your outdoor unit can't start. The contactor should not be installed in placed which are too hot. unit without such background may result in product damage, personal injury, or death. The disconnect box enables the air conditioning unit to be turned off outside. The cause of you AC freezing up is not enough air flow over the coils. That contactor had a stuck main contact where the AC unit continued to run, freezing up the coil. My A/C will not run - can a bad compressor contactor cause the 24V transformer to burn out? So, my upstairs A/C unit wouldn't run. Will a bad contactor, run capacitor or relay cause the A. How to Select and Size an IEC Contactor. Communication between the outside unit and the inside unit is a wholly different low voltage circuit independent of the capacitors. As further shown in FIG. Air Conditioning Denver : Troubleshooting a low voltage short by Weatherwise on 06/19/11 Low voltage shorts in your air conditioning system are some of the most difficult failures to diagnose. I wonder if you don't have a bad contactor. The central air condensing unit is energized with 240 volts of electricity. Common air conditioning problems can mean too many days suffering. buzzing is on the low voltage side of the contactor. This could be a sign that the contactor has melted, leaving the air conditioner with no means to block electricity. Contactors usually need to be changed every 5 years under normal operation. The contactor should not be installed in placed which are too hot. I had my wife turn the thermostat on and off a couple times and I could hear a click on the outdoor condenser unit, but I'm not exactly sure what was clicking. So you visited the outside unit and noticed that the fan wasn’t spinning. 2) Condensing Unit Frozen Wont Turn Off - The other possibility for your problem is the thermostat wires are bad somewhere. It could be the contactor. Refer to unit wiring diagram. When the thermostat calls for cooling it sends 24VAC to the contactor coil, energizing it, which turns on the outside unit (both compressor and condenser fan). graycoolingman. This can be caused by a weed-whacker hitting the wire outside, or a wire-staple digging into the wire too tightly, rodents chewing on it, or just bad wire. The AC is about 5 years old, and worked perfect. Damaged or missing isolation feet. A bad capacitor on the outside unit for the compressor and condensing fan motor has no effect whatsoever with the indoor blower. Best Answer: The outside unit contains the compressor, the condenser and the condenser cooling fan. humming, you know you have 24 vac power from the indoor unit to the outdoor unit. Could you tell what could this possible be? Could it be the contactor gone bad or what? Please help me out this matter. Checked fan. If that is not happening the low voltage is not being sent to the outside unit or the contactor is bad. The good news is, it's pretty easy to find out. Oh well, I'm out of ideas. Another cause would be a shorted thermostat cable. Common air conditioning problems can mean too many days suffering. When replacing an air conditioning contactor, Be sure the control voltage rating is correct, Be sure the load capacity (amperage) is correct, Try to get a contactor with the same number of poles, Try to get a contactor with terminals that match the original, And always follow safety precautions. Continue testing all the way out to the outdoor unit's contactor. Refer to unit wiring diagram. Condenser coil fan problems: The condenser coil fan is responsible for cooling your outside A/C unit’s condenser coils. Electrician doesn't replace capacitor, it is the job of an instrumentation mechanic or an electronic technician. If the contactor in your AC unit fails, the compressor can't send out the refrigerant needed. I wanted to title this: Outside unit running, but thermostat is off but I'm 99% sure its the contactor unless someone here says otherwise. The reason for 3 pole is that I had a HVAC guy fix my unit last August, and he didn't have the right contactor on his truck so he subbed in a 3 pole. The condenser unit is making a loud noise and the fan and the compressor is working. How does it work? The condenser is connected to the house via an electrical box called a quick disconnect I call it yank out. Problem: My Air conditioner's contactor will not engage. If you have a multimeter, turn the air conditioner on and measure the voltage drop across the contactor. The heat pump and heat strip DIP switches are both set to the ON position in one zone. If there is voltage at the contactor (red and white wires) and you push the contactor in, does it stay in, or does it come right back out?. A start capacitor is an electric device that gets the electric motor running at startup by providing a "jolt" of stored elect. While the compressor is running, the capacitor is cycling on and off thousands of times a second. OrangeTractorTalks - Everything Kubota > Kubota Talk > Off Topic: Any residential hvac guys here?. At higher outdoor and water temperatures a higher flow rate may be required for proper operation. Is the fan blowing? If not replace outdoor fan motor or the fan capacitor. When the termostat is in the cold position and the temperature its set is lower than the one inside the house the. Turn the power on to the outdoor unit. this would be the the contactor energized. This can be caused by a weed-whacker hitting the wire outside, or a wire-staple digging into the wire too tightly, rodents chewing on it, or just bad wire. The contactor was an easy replacement of the contactor in our AC unit. Bad contactor ac unit keyword after analyzing the system lists the list of keywords related and the list of websites with related content, in addition you can see which keywords most interested customers on the this website. I looked at some of your earlier post and decided to replace contactor. In a central air conditioning system air is drawn into the ductwork system through the return air ductwork. After that, the main power cord of the split air conditioning unit is connected to this disconnecting means from one side, the other side is connected to the terminal box in the indoor unit (see Fig. If the outside fan isn't running, unless it's raining on the unit, it won't be able to reject the heat and the line sets would get warmer with each second of run time. The coil energizes the contactor, moving the contacts into position. One way to tell for sure if a motor is going bad is to let it run for 5-10 minutes. Check to insure the coil is getting voltage to switch the contacts. At higher outdoor and water temperatures a higher flow rate may be required for proper operation. A corrosive environment which contains damaging chemicals or vapors can also cause damage to the contactor coil. 1705: Line Contactor Short Circuit This trip occurs when the controller detects that the line contactor’s ‘contacts’ are welded. this would be the the contactor energized. Since it is closed i. Turn the thermostat to ON and COOL like you normally would. That safety device must be able to conduct electricity through the switch, as well as trip the unit out of the circuit when an unsafe condition occurs. Many of those holes were close to where the filter retainer angles go, so I just made a few adjustments to help them serve double-duty. goodman parts relays. Is your air conditioner leaking water inside or outside your house or business? Excessive condensation from air conditioning is a sign you have an ac issue. Have home AC compressor questions?. We are in Rio Rancho New Mexico and it is a sunny day with an air temp of 91. A start capacitor is an electric device that gets the electric motor running at startup by providing a "jolt" of stored elect. If thermostat wire checks out OK, check wiring inside the unit control box. Examine all the wiring in your HVAC unit, especially the wiring which connects it to an outlet. You can also push in the contactor and see if the fan and compressor start. It is, therefore, necessary to take time and effort to put your fan on a solid base. , House, 2 replies. It may look like the contactor in the picture or it may be similar, but have a metal bar across the top. The Capacitor and Contactor are a Team. Contactors are generally inexpensive and the best place to start. The contactor was an easy replacement of the contactor in our AC unit. When I manually depress the contactor (I guess, it's the spring loaded "button" in the middle) the fan comes on but stops as soon as I release it. Walking outdoors to find a puddle of water underneath your AC's condenser unit might be alarming, but it's important to understand when an air conditioner leaking water is normal and when it may indicate an issue with your unit that requires air conditioner repair services. There are two possible scenarios here: Scenario A: You hear the outdoor unit’s compressor working and the fan isn’t spinning. Cooling well till yesterday and outside unit would not come on, fan and compressor, no joy. If that is not happening the low voltage is not being sent to the outside unit or the contactor is bad. 9 Things to Check Before Calling for A/C Service. A good cleaning will help your AC unit to function more efficiently, and potentially make it last longer too. Description: This is the procedure and information for replacing a contactor on an air conditioner. It doesn't tell you anything a volt meter won't, and it risks your equipment if there is no charge or a leak in the system. Switches, Keys and Displays 24. HVAC Troubleshooting: How to Fix Loud & Strange Noises Coming From Your AC Unit. This procedure applies to almost every air conditioning and heat pump system on the market. Condenser air enters from three sides. So I began the process of figuring out what was wrong by going outside to check on the condenser unit. Home Improvement → How to diagnose what part of the outside A/C Unit is bad? uniqs contactor could be badly pitted and burned it might pull in on 24v but not activate the high volt stuff. If there is voltage at the contactor (red and white wires) and you push the contactor in, does it stay in, or does it come right back out?. So the AC runs and runs trying to disperse that heat outside until-click-the breaker trips due to drawing too much. Neither the fan nor the compressor were running. You could slap the unit, and hear the contactor chatter.