ABC Blog

Air Conditioner Starts Then Stops After Only a Few Seconds

a home with a malfunctioning AC

Nothing feels better than turning on the air conditioner on a hot and humid day. But, that joy turns into frustration when the air conditioner starts and then stops after only a few seconds. This issue is called “short cycling.” While it is a fairly common problem in AC units, it is a sign that something is wrong. It’s best to resolve it quickly before it leads to more expensive repairs.

If your AC has been short cycling, here are the most common causes and what can be done to fix your unit. In more complex cases, the smart move is to contact an HVAC professional who can address the problem.

Malfunctioning Thermostat

Thermostats help air conditioners achieve your desired room temperature. If you set it to 65 degrees Fahrenheit, the thermostat will turn the AC on and off to maintain the right temperature. But if the thermostat is malfunctioning, it can’t sense the temperature in the room properly. It could be thinking that the temperature is below 65 degrees, causing the AC to turn off when you switch it on.

Replace your thermostat’s batteries to see if this will fix the problem. If it doesn’t, the electrical and mechanical parts in the AC might be dirty, affecting the thermostat’s performance. You can clean these parts with a soft brush to see if it resolves the issue. If not, get the help of an HVAC expert.

Refrigerant Issues

AC units can’t function without refrigerant. Refrigerant is a heat-absorbing medium that flows inside the AC, continuously transforming from gas to liquid and vice versa. When refrigerant levels are low, or the refrigerant is leaking, the compressor can’t operate, causing the unit to shut down. In addition, refrigerant leaks are hazardous.

If you suspect a refrigerant issue, don’t attempt to resolve it yourself. Contact an HVAC specialist immediately so they can address the situation and have your AC running smoothly again.

Compressor Damage

The compressor is what makes the vapor compression cycle possible. It compresses the refrigerant, causing its temperature and pressure to rise. However, the compressor can overheat, or some parts can get damaged. When these issues happen, the compressor will shut down and cause the AC to turn off.

The best thing to do is to check your compressor’s warranty and have it replaced if the coverage is still valid. But if your AC is older than ten years, it might be better to replace the whole unit. It is probably nearing the end of its life, so replacing just the compressor would be a waste of money. An HVAC professional can assess the situation, pinpoint the cause and provide a cost-effective solution.

Dirty or Frozen Coils

The condenser coil is where the refrigerant releases the heat absorbed from the air. If the condenser coil is dirty, your AC can’t complete the cooling process. It can cause the unit to malfunction and shut down whenever you turn it on. To avoid this, clean the condenser coil regularly. You can use a coil brush to clear debris and a fin comb to realign the coil fins.

Another possible reason your AC is short cycling is that the evaporator coils are frozen on your AC unit. When this happens, your unit will become less efficient and might turn off. A refrigerant leak may be the culprit behind a frozen evaporator coil, so let an HVAC technician deal with the problem.

Malfunctioning Run Capacitor

The run capacitor provides an energy boost when you turn the AC on. It also helps the unit run by supplying it with power. But if the run capacitor is malfunctioning, the power supply will get cut off and cause the unit to turn off after a few seconds.

Never attempt to fix a faulty run capacitor because it contains an electrical charge. Have an HVAC specialist look at your unit so they can replace the run capacitor if necessary. Always let an expert deal with electrical problems you may be experiencing with your AC.

Oversized Unit

If your air conditioner starts and stops after only a few seconds, you might have an oversized unit. When your AC is too big and powerful for your home, it will cool the space quickly and then turn off. That can cause your electricity bill to increase and damage the unit.

It’s important to pick an AC with the right tonnage for your home. A one-ton unit can typically absorb 12,000 BTU of heat per hour from a 500-square-foot space. However, consider other factors like the number of people in the room and sun exposure. An air conditioning specialist can determine the correct AC unit for your home.

Clogged Air Filters

There might be a simple reason behind an AC that keeps turning off–dirty air filters. The air in your home carries dirt, dust and debris, and the air filter traps all these particles. But it can become clogged over time, and when that happens, it can cause the unit to short cycle. It also makes the AC work harder, raising your electricity bill.

The best way to prevent this is by knowing how often to change the air filter in your house. Generally, professionals recommend swapping out your filter for a fresh one or cleaning your filter every one to two months.

A living room

Why Your AC Makes a Hissing Noise When Turned On

If your AC makes a hissing noise when turned on, it doesn’t always indicate a problem. You shouldn’t worry if the sound goes away after a few seconds. But, if it continues the entire time the AC is on, there could be an underlying issue. Here are the possible reasons why your unit is hissing.

Leaking Air Ducts

As with any AC part, the air ducts can deteriorate over time and develop cracks and gaps. If you hear a high-pitched hissing in the air vents, that is probably the sound of pressurized air leaking through the AC ducts.

Another way to tell if you have leaking air ducts is if your unit can’t cool the room. That is because the cool air is escaping into other areas like the ceiling or attic. Another clue is if your electricity bill is higher than usual since your unit is working harder to lower the temperature in the room.

Faulty Expansion Valve

The expansion valve is crucial to the cooling process. It lowers the pressure of the refrigerant, allowing it to change from liquid to vapor. It’s not a cause for worry when the expansion valve makes a soft hissing sound as the refrigerant flows through it. But, if the noise becomes louder and more persistent, it could mean the expansion valve is faulty.

If the hissing worsens, contact an HVAC professional to assess your unit. Fixing the expansion valve will be less expensive the earlier you address the issue.

Refrigerant Leak

Another common culprit behind a hissing AC is a refrigerant leak. Even the tiniest leak can make a noticeable noise because of the high pressure inside the coils. The older your unit, the more prone it is to refrigerant leaks. Corrosion and debris can also cause this issue.

To prevent refrigerant leaks, your HVAC technician should perform an air test during installation. It’s a way to check if the coils can withstand continuous pressure as the AC runs.

High Compressor Pressure

The compressor is responsible for moving the refrigerant throughout the HVAC system. If it develops a leak or there’s too much pressure buildup inside, you might hear a high-pitched hissing noise. Turn the unit off and contact an AC repair specialist if you hear any sound from the compressor.

Fortunately, the latest models have a system failsafe that automatically turns the AC off if the pressure is too high. But whether your unit is old or new, let an HVAC technician inspect it if it is hissing.

an AC unit

What To Do When the AC Drain Pan Is Full of Water

If your AC isn’t working, you might want to check the drain pan. If it’s full of water, that’s a sign of a clogged drainpipe. The humidity inside an HVAC system creates a perfect breeding ground for mold and bacteria, which can eventually block the drainpipe.

The easiest way to solve this problem is with a wet/dry vacuum. Use it to suck up the water on the drain pan and any blockages inside the drainpipe.

Turn to the Pros for Your AC’s Regular Maintenance and Repairs

While air conditioners bring immense relief on hot summer days, they can also develop issues and cause unnecessary stress. That is why homeowners should sign up for AC preventative maintenance.

Contact an HVAC technician if you’re experiencing AC problems such as short cycling, hissing or blocked drain lines. They have the knowledge, tools and expertise to address the issue and get your AC running smoothly again.

ABC Can Get Your Air Conditioner Working Again

It can be concerning when noises are coming from your unit or if your unit isn’t working correctly. No matter what issue you’re experiencing, ABC Home & Commercial Services can help. Our pros are licensed and will be able to quickly diagnose your AC problem. Then, we can get to work on making all the needed repairs.

Learn More

Comments are closed.