When an Air Conditioner Turns On…[Problems Solved]

If you notice issues when an air conditioner turns on, this article shows steps to troubleshoot and fix the problems.

when an air conditioner turns on

Smell When an Air Conditioner Turns On – Fixed

Several issues can cause an air conditioner to smell, especially when you turn it on, such as the air filter and drain. If you do not regularly service the air conditioner, the air filter gets dirty, the drain may have debris clogging it, the evaporator coil may have mildew, and the drain pan may have standing water. 

Also, the ductwork may have dead rodents, or long periods of inactivity may cause a bad smell to come out of the air conditioner. Find helpful resources in this article on an air conditioner smelling bad when turned on to help you fix the problem.

Loud Noise When Air Conditioner Turns On – Solved

The following are possible noises an air conditioner can make when you turn it on or when it is running, and how to fix each one:

1. Banging Noise

The compressor may bang when you turn your air conditioner on or when it is working. An aging compressor can make this noise; the same applies if the compressor has internal faults. Compressors have long lifespans, so they do not usually fail prematurely. However, moisture, voltage surges, or age can wear them out. You may not have to replace a noisy compressor if it is still working. But if the noise is a disturbance, consider replacing it only after checking its cost-effectiveness.

2. Buzzing Noise

Buzzing from an air conditioner may indicate faults with the condenser fan motor or blades. It may also stem from other loose parts in the air conditioner. You may also hear buzzing near the copper refrigerant lines, indicating a leak. It is crucial that you get a professional HVAC technician to check the fan motor and internal parts and determine whether or not there is a refrigerant leak. Consider paying for cleaning the condenser coil because it can create buzzing when it is dirty.

3. Humming Noise

A defective contactor relay switch causes this noise. It is a tiny switch that turns on the outdoor condensing unit when the thermostat sends a signal. If the switch fails to work, the outdoor unit may not work. Get professional help to check the switch and compressor to ensure none of these parts is faulty. Also, the technician can check for electrical issues because such issues can cause buzzing in the system. Otherwise, the air conditioner may not run.

4. Screeching Noise

A loud screeching or shrieking noise may indicate a problem with the condenser fan. The fan works with the condenser coil to dissipate heat from the air conditioner to prevent overheating. If the blower motor fails, you may also hear this noise from the indoor unit. 

The blower is the fan that circulates cold air inside the house. Test each fan’s motor with a multimeter to check for continuity and replace any faulty ones. If the motor’s bearings are worn, it will produce a loud noise, and the only repair is to replace the motor.

5. Clicking Noise

Clicking from an air conditioner may tell you when the unit starts and ends a cooling cycle. So, it may be normal and nothing to worry about unless it is a continuous sound. If that is the case, you may have a faulty thermostat. Turn it off, wait a few minutes, and turn it on again. If the clicking stops while the thermostat is off and resumes when it is on, it is time to replace it. Have a technician run diagnostics and replace the component if necessary.

Additionally, the relay may cause the compressor to click on and off if it is defective. That means you have to test the relay to determine whether or not it needs a replacement. Follow the air conditioner user guide instructions to troubleshoot the relay and replace it if it no longer works.

6. Rattling Noise

Loose parts inside the air conditioner cause the unit to rattle when it runs. The noise may also come from debris in the outdoor condensing unit. So, check the condenser to see if there are pieces of dirt stuck in it; open the grate and clean out the debris to stop the noise. This is an easy solution to the noise. However, if it is an internal component, you may need the help of a professional HVAC technician to fix it. The contractor may be faulty or loose, rattling around inside the unit, which is dangerous to the compressor.

7. Bubbling Noise

Excess condensation or moisture in an air conditioner creates a bubbling sound. Check the drain to see if there is any damage to it. That may explain the noise, and you may have to patch or replace it. You can remove and replace the damaged drain pipe if you have the training. Otherwise, employ the services of a technician to fix the drain.

8. Hissing Noise

Hissing may signify an air or gas leak. It is more likely to be a moderate or severe air leak from the ductwork, which needs immediate attention. The air filter may be the wrong size or type for your air conditioner, or the expansion valve may be damaged. One or both issues can cause hissing from the unit. If you suspect a fault with the expansion valve, call a technician to inspect, test, and fix it.

Sometimes, the refrigerant makes noise as it flows through the cooling lines to the air conditioner. While the noise may sound loud sometimes, it is normal. However, you should have a technician check the system if the noise increases and becomes constant.

Having regular maintenance and tune-ups for your air conditioner is crucial to how well the unit runs. It helps to prevent minor issues and errors that can cause noises and functional issues. Contact the air conditioner manufacturer or hire an independent HVAC technician.

Lights Dim When Air Conditioner Turns On – Quick Fix

It may not be anything to worry about if the lights dim or flicker when you turn your air conditioner on; air conditioners require a lot of voltage to start. They may draw electricity supplied to other parts of the house, including the lights, causing them to dim or flicker. In other words, it is normal to find the lights only about five percent dimmer than usual, or they flicker or dim for only a few seconds.

However, if the lights dim or flicker for longer than a few seconds, there may be a problem with the wiring or an internal component. If the wiring is loose or burnt, it can affect the lights when you turn on the air conditioning since it needs a lot of electricity to start. The wiring must be in good order to carry the unit, so have an electrician check the house and determine whether or not it needs rewiring.

Another part to check is the capacitor. If the lights dim by more than 25% when you turn on the air conditioner, the compressor may be failing. And one of the primary reasons a compressor fails is a faulty capacitor. The capacitor acts like a battery that stores power and allows the compressor to run. If the capacitor is bad, the compressor may have difficulty starting, causing it to draw too much voltage in its effort to run. 

Consequently, the lights may dim, and you may notice small appliances having interruptions. If you suspect the capacitor is not working well, hire an appliance technician to test it and determine whether or not it needs a replacement. Capacitors store electricity that must be discharged before you can test them. Touching the capacitor without discharging it is dangerous.

You may want to use a hard-start kit to boost the compressor during start-up. That way, it can start smoothly and run without pulling too much electricity or dimming the lights. It also preserves the compressor’s life since it does not have to strain itself to start.

Another possibility is that the air conditioner is connected to the same circuit as other appliances. As mentioned, an air conditioner requires a higher voltage supply than many other appliances, so it needs a separate circuit to run. Connecting it to one circuit that carries other appliances reduces the voltage supply to the house. 

Otherwise, the circuit becomes overloaded. You may want to disconnect other appliances on the circuit and leave only the air conditioner. That temporarily fixes the problem, but you will need a long-term solution. A technician should check the circuits and reconnect other appliances to avoid overloading, which may become a fire hazard.

Sneezing When Air Conditioner Comes On – What to Do

You may have an air conditioner allergy if you tend to sneeze when the appliance comes on or if you walk into a place with one. Leave the room with the air conditioner to a place with fresh air, and see if the sneezing continues. If you feel better when you leave the room, you are allergic to what is in the air. The air conditioner may release air with pollutants, to which you react.

One of the best ways to tackle this problem is to check the air filter. The filter traps all pollutants in the air and ensures they do not enter the room air. That way, you have cleaner air to breathe. However, the filter gets clogged with dirt over time and requires cleaning or replacement. If you do not replace it, it becomes unable to clean the air and may release some of the older dirt it trapped. 

Consequently, it fills the air with contaminants that may irritate your sinuses and cause your allergies to act up. Always replace the filter every two months, and use one with a high MERV rating for better air purification. Get a professional to maintain the air conditioner and change the filter, especially if you cannot touch the dusty one due to your allergies.

Other Solutions

An air purifier may make your air cleaner and prevent sneezing whenever you turn on the air conditioner. An air purifier typically uses electrostatic fields and a HEPA filter to remove small and large particles from the air. In other words, it is a lifesaver if you are prone to allergies, so you may want to use it to keep the air in your home pure. This is especially true if cleaning the air conditioner does not stop your allergic reactions to it.

You may also want to find a way to maintain the humidity level in your home. Mold and mildew thrive where the humidity is high, so keep the level at 50 or lower. Low humidity levels discourage the growth of mold and dust mites and reduce the risk of allergies. And while your air conditioner can control the humidity in your house, it may not always be enough. Therefore, consider investing in a dehumidifier. Open windows for better air circulation when the air feels dry.

Additionally, regularly clean the air conditioner. Bacteria and other microorganisms thrive in damp, dark, and dirty places, and your air conditioner is an excellent breeding ground for them. It does not matter what air conditioning system you have; regular maintenance lowers the risk of mold growth and improves the air quality. You can clean your home’s air conditioner yourself or have a professional do the job. This is particularly true if you have a ducted system.

Important Note

Keep the beddings and linens in your home clean as much as possible. The reason is that pollen and other airborne allergens easily stick to these materials and pollute the air. Therefore, regularly wash them in hot or warm water if you notice a spike in your allergic reactions.

Engine Dies When the Air Conditioner Is Turned On – Solutions

The following are the possible reasons your car’s engine shuts off or dies when your turn on the air conditioner:

1. The Idle Air Control Valve Is Faulty

The idle air control valve (IAC) raises and lowers your car’s engine’s revolutions per minute (RPM). This regulation enables the engine to keep running even when there is an extra load on it, such as when you turn on the air conditioner. The valve is the most likely cause of the engine problem because carbon tends to build up on it over time, reducing its capacity to function. Fortunately, you can clean the valve with a solvent to remove the carbon buildup.

2. The Compressor Has Seized

The compressor processes the refrigerant for circulation in the air conditioner. It requires a lot of power to move the refrigerant when it is in a high-pressure state. Typically, the compressor uses five to ten horsepower, which reduces the RPM. The power required increases if the compressor seizes because it will strain itself to turn against the motor bearings.

This pressure exerts the car’s engine and causes it to shut off. If you continue using the air conditioner like that, it may eventually wear the engine out and damage the car. Consider replacing the compressor, although it is usually an expensive repair.

3. The Belt Is Old

The drive belt with which the compressor operates may be too old to carry the motor. When you turn on the air conditioner in your car, the compressor turns on, and the drive belt rotates it. If the belt is too worn to carry the compressor, it slips off and causes RPM fluctuations. The fluctuations put too much pressure on the engine and cause it to shut off. Let an auto mechanic check the drive belt and determine whether or not they can salvage it or replace it.

4. There Are Electrical Problem

Electrical issues such as a damaged relay, a corroded capacitor, or a blown fuse can affect the engine. A technician best handles this type of problem to ensure the right component is fixed without any damage to the engine or other parts.

5. The Electronic Throttle Body Is Defective

This part functions like the idle air control valve; newer cars have the throttle body in the place of the valve. Your auto mechanic is equipped to handle the electronically-controlled part and see if there is a carbon buildup. S simple cleaning process can fix the problem and free up the air passageway so that the engine does not overwork itself and turn off.

Too much refrigerant in the air conditioning system can also cause the car’s engine to shut down. The air conditioner should not have too little or too much refrigerant; it must be the right amount for the system. Otherwise, pressure builds on the engine, forcing it to sputter and go off while the air conditioner runs.

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