Why Is My AC Not Turning On?

An AC that won’t turn on is a frustrating experience that most homeowners have had to deal with or will at some point. If you experience an AC that won’t turn on, it is usually a good idea to contact a local HVAC technician. A professional will be able to spot the underlying issue quickly and correct it in a reliable manner. With that in mind, let’s explore the most common problems and what could cause them.

Thermostat Troubles

The thermostat is the first thing to check because it is what controls the air conditioner. If your thermostat runs on batteries, the first step is to change them. Also, check that the brightness level is high enough to see the display. Next, ensure that the thermostat is on and in cool mode. Additionally, check the temperature setting. You can turn it down a few degrees to see if your AC turns on. If your cooling system engages, it could mean your thermostat is working but needs to be recalibrated. If none of these solutions work, it is probably time to call a professional to diagnose the issue and fix your thermostat.

On and Off Switch

Many AC systems have a shutoff switch. If you have a split system, your indoor as well as your outdoor units may have their own switches. Check these to ensure that someone has not inadvertently toggled them. A wiring fault is possible as well. This problem is something that your HVAC technician can solve.

HVAC Disconnect

In addition to on and off switches, most systems have an HVAC disconnect. A disconnect is a large industrial switch located outside the home. They are usually positioned in a metal box on the siding near the outside unit. Building codes in some areas require disconnects as they provide an easy and fast way to turn off power to the system. Check your disconnect to ensure that no one has pulled or pushed it into the off position.

Tripped Circuit Breaker

Check your electrical panel to ensure that the circuit breaker for the AC is not tripped. In older homes, you may have a fuse instead. Fuses blow rather than trip. This can happen due to irregularities in the power steam. Reset the circuit breaker or replace the fuse as needed. Some ACs have a reset button. If yours does, go ahead and press it. Turn the AC on.

Stop and call a technician if the circuit breaker trips or the fuse blows again. Do not continue resetting the system. This situation points to a more serious systemic issue. There may be a short circuit. It is also possible that an AC part is malfunctioning or has failed. An issue with the electrical panel or home wiring is also possible. A professional will have to identify the issues and solve them to prevent safety issues or damage to your cooling system.

Blown Fuse

The HVAC system has its own fuses as well. These are there to protect the system from high amperage. They can blow due to internal or external power surges. They can also wear out over time and fail. You can use a multimeter to test the AC fuse. Replace it if necessary. Note that the electrical system in an AC can be dangerous. Even something as seemingly simple as checking and replacing a fuse should be performed by a professional.

Other Electrical Issues

While we’ve covered the most common problems so far, there is a wide range of potential electrical issues with a cooling system. These can include frayed wiring or electrical connections that have become loose over time due to vibrations. A power surge may have damaged the control board in your air conditioner. A professional can quickly solve any of these electrical system-related problems.

Clogged Air Filter

Dirty air filters are often the issue when a homeowner’s cooling system stops running or will not turn on. A clogged filter prevents proper airflow through your air conditioner and can cause it to overhead. Your system has safety features that will cause it to shut down if it gets too hot. If you see a layer of dirt and grime accumulation on a filter, this generally means it’s clogged. Try changing the filter and turning your system back on after giving it time to cool down.

Blocked Condensate Drain Line

Removing moisture from the air is a byproduct of air conditioning. That moisture must go somewhere. Central units have a drip pan to capture this moisture. A drain line is connected to the drip pan, allowing moisture to exit the home to the outdoors. Condensate lines can clog over time. If this happens, the drip pan fills up and eventually trips the wet switch. The wet switch turns the system off to prevent flooding and damage to your air conditioner. If this is the problem, it’s generally easy to verify as the drip pan will have standing water. It can also be that the wet switch is malfunctioning.

Cleaning out a condensate line is a relatively simple task for a HVAC technician. If the AC has recently been installed, it may be that the drain line was positioned incorrectly. If it does not have the right angle, moisture will drain slowly or not at all. This can cause the drip pan to fill up over time and eventually trip the sensor.

Fauty Blower or Air Handler

The blower is what moves cool air into your ductwork to be distributed throughout your home. The air handler contains the blower and other components. These systems have many moving parts and are prone to failure over time. The issue with your air conditioning can be as simple as a bad ball bearing in the blower’s motor. It can also be that the motor has burned out and needs to be replaced by a professional.

Dirty or Frozen Evaporator Coils

The evaporator coils contain refrigerant and transfer heat energy. These can become dirty over time. This is a primary reason HVAC experts recommend seasonal maintenance. During a tune-up, your technician will clean the coils. The coils can also ice over. There are many reasons this can happen. The most common reason is a clogged air filter.

Refrigerant Leak

A refrigerant leak will not trip the system right away. It will result in decreased performance. As refrigerant pressure drops, the system will have to work harder. This will result in higher power usage. This may damage the capacitor or otherwise cause its circuit breaker to trip.

Dirty Condenser Coils

Condenser coils can become dirty with time as well. Your technician will also clean these during a tune-up. Note that dirty condenser coils will often manifest as other symptoms before the system does not turn on. These include rising energy costs, short cycling, high humidity, and uneven cooling.

Local AC Experts in Aikin

Northern Air Plumbing & Heating has served Aitkin and the surrounding areas since 1991. That’s more than three decades of diagnosing and fixing AC issues, giving our team the experience to solve your AC woes quickly. We also install, maintain, and repair heating systems. Additionally, we are indoor air quality experts and provide plumbing services such as drain cleaning and installing water heaters and water treatment systems. Contact us today to schedule an appointment with one of our HVAC technicians.

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