4 Reasons Why AC Compressor Not Working But Fan Is Running (2024)

Understanding Reasons For AC Compressor Not Working But Fan Is Running

What is an HVAC Compressor?

Have you ever wondered why your AC compressor is not working? The compressor is an integral part of the air conditioning system. Its role is to carry heat out of the house while compressing the refrigerant fluid. The warmed refrigerant is heated up further, which converts it from its gaseous state into liquid. The refrigerant’s temperature should always be higher than its surrounding environment. Heat still transfers from warm to cool areas. For the heat to be transferred out efficiently, the compressor needs to be appropriately maintained and in working condition. In most cases, if the AC is not working, the root of the problem often traces back to the HVAC compressor.

The heat of summer can be intense, and the worst thing that can happen is finding yourself with a malfunctioning HVAC compressor. A working AC will provide you with nice and cold air as opposed to bearing the brunt of warm, dry air. With how much the HVAC runs, something is bound to go wrong with its compressor. However, having the fan running but the compressor not working is nothing too dire, so don’t panic. Here’s an insight as to why that could be happening.

AC Compressor Not Working But Fan Is Running: What’s the Cause?

When turning on the AC, you may notice the fan running when the compressor is not. In most cases, the problem is usually simple enough for a DIY quick fix, but there are instances when an HVAC technician may be required.

i. Dirty Coil And Filters

A build-up of debris and dirt in the filters, evaporators, or condenser soil can result in the entire unit shutting down. A clogged air filter reduces the airflow significantly, such that the evaporator coil stops functioning. Clogged air filters and condenser coils put the compressor under pressure, making it overheat. Best case scenario, the compressor automatically shuts down before getting damaged. Otherwise, the continuous overheating may necessitate the compressor getting replaced. Wash the condenser coils, replace the air filters, and clear out all blockages and obstructions in the supply vents for air to flow freely.

ii. Capacitor And Starter Relay Problems

The starter relays and capacitors are integral in supplying power to the compressor. They are the most prevalent cause of compressor problems. The capacitor provides the power needed to start and run the compressor, the blower motor, and the outer fan. The starter relay transmits power from the capacitors to the compressor. When the AC compressor is not working but you hear some humming sounds from the unit, chances are the compressor is trying to access a non-operational capacitor. The upside is that they are the easiest and cheapest parts to replace.

iii. Dead Compressor

This can result from a simple issue like a faulty capacitor or an overheating unit. The only option with a dead compressor is a replacement. Note that an expert should do a compressor replacement.

iv. Power Issues

When the AC compressor is not working but the fan is running, chances are the outer unit housing the compressor isn’t receiving power. The fan keeps running because the central unit has no such problem. If the compressor isn’t starting, check the wiring connecting the two units. If it’s a blown fuse or tripped circuit breaker, the search has come to an end.

Other potential causes may include a faulty thermostat, mismatched indoor and outdoor units, or the AC may just be old.

Is Your AC Compressor Not Working, But Fan is Running?

If your AC compressor is not functioning, here are some situations you may face:

• Warm, dry air coming from the running fan.
• The circuit breaker keeps tripping.
• The compressor stops altogether.
• Strange noises and shaking from the outdoor unit.

It’s Time to Fix AC Compressor Not Working, but Fan is Running

The compressor is at the center and heart of the AC unit. An expert AC technician will make a recommendation of whether to replace or repair the compressor. A pro in the industry can fix it before the utility begins to rack up.

How Do I Prevent AC Compressor Not Working, but Fan is Running?

Regular maintenance of the unit is the best preventative measure since it solves most of the issues before they escalate. The compressor is made up of several pieces that are easily replaceable. With regular inspections, the part failing is spotted early enough and replaced, effectively preventing the risk of having an AC compressor problem.

Regular maintenance checks not only keep your unit in optimal working condition but also extend its lifespan. Make it a habit to schedule these checks at least twice a year, especially before the peak summer and winter seasons. This helps catch potential issues like a fan kicking on but the compressor not working, ensuring that the split AC compressor is running efficiently. Regular checks also prevent situations where the window AC compressor is not working but the fan is running.

Common Scenarios: Fan Kicks On But Compressor Not Working

• AC Not Kicking On But Fan Works: This issue often points to problems with the electrical components or a malfunctioning thermostat. A tripped circuit breaker, a blown fuse, or faulty wiring can prevent the compressor from receiving power, while the fan continues to operate normally. Additionally, a thermostat not set correctly can fail to signal the compressor to start.

• AC Fan Running But Not Compressor: One of the most common causes is a bad compressor capacitor. The capacitor powers both the compressor and the fan; if the compressor side fails, the fan can still run. Another possibility is a malfunctioning contactor, which fails to transmit electrical power to the compressor.

• Fan Turns On But Not AC: This can occur due to issues with the start relay or the capacitor. These components are responsible for initiating the compressor’s operation. If either is faulty, the compressor won’t start, though the fan might still run. Other potential causes include power supply issues or a dead compressor.

• AC Won’t Turn On But Fan Does: This scenario often indicates a problem with the power supply to the compressor, such as a tripped breaker or a blown fuse. It could also be due to faulty wiring or a malfunctioning capacitor that fails to start the compressor.

• AC Compressor Won’t Kick On: If the compressor doesn’t start, it could be due to a faulty start relay, capacitor, or a bad contactor. These components are crucial for delivering the initial surge of power needed to start the compressor.

• AC Not Cooling But Fan Is Running: This typically means the compressor isn’t working, possibly due to low refrigerant levels triggering a low-pressure switch, a dirty condenser coil causing the compressor to overheat, or a defective capacitor.

• Why Is My AC Compressor Not Turning On?: Various factors could be responsible, including electrical faults, capacitor issues, thermostat problems, or a dead compressor. Each of these components plays a crucial role in the functioning of the compressor and needs to be checked systematically.

• AC Compressor Tries To Start But Won’t: This often indicates a problem with the capacitor or internal faults within the compressor. A humming sound from the outdoor unit can be a sign that the compressor is struggling to start due to a faulty capacitor.

• Condenser Fan Running But Not Compressor: This issue could point to power supply problems or a failing compressor. Check the circuit breakers, fuses, and the wiring connecting the outdoor and indoor units.

• Air Conditioner Fan Running But Not Compressor: This situation often requires checking the electrical connections, capacitor, and the contactor. Any fault in these components can prevent the compressor from receiving power while the fan continues to run.

• AC Compressor Not Kicking On: Persistent issues with the compressor not kicking on often require professional diagnosis and repair.
• Compressor Not Running: This could be due to power supply issues, internal faults, or external damage to the unit.
• My AC Compressor Won’t Turn On: This is a common issue often related to electrical or mechanical faults within the compressor unit.
• Outside Compressor Not Running: If the outside compressor is not running, it could be due to power issues or a faulty relay.
• Air Handler Running But Not Compressor: This indicates a disconnection between the air handler and the compressor, often due to electrical issues.
• AC Compressor Not Coming On: This can result from a range of issues from power supply problems to internal mechanical failures.
• Compressor Not Kicking On: This requires checking the start relay, capacitor, and power supply.
• Fan Running But Compressor Not: A common issue that often requires checking the capacitor, relay, and electrical connections.
• Air Handler Turns On But Not Compressor: This points to a potential disconnect in the power supply or control system.
• AC Only Fan Working: If only the fan is working, it means the compressor isn’t receiving the necessary power or there is an internal fault.
• AC Fan Comes On But Not Compressor: This scenario often requires a check of the electrical connections and the condition of the capacitor.
• AC Not Working But Fan Is Running: This indicates that while the fan is operational, the compressor or the unit as a whole is malfunctioning.
• Air Conditioner Fan Turns On But Compressor Does Not: This situation often points to a fault in the power supply or an internal compressor issue.
• AC Fan Runs But Not Compressor: A running fan without the compressor often means electrical issues or a faulty capacitor.
• What Would Cause AC Compressor Not To Kick On: Several factors including power supply issues, faulty capacitors, and internal mechanical failures can prevent the compressor from kicking on.
• AC Not Turning On But Fan Works: This usually points to issues with the compressor’s power supply or an internal fault.
• Compressor Not Turning On AC: This indicates a significant issue within the compressor unit, often requiring professional attention.

By understanding these common scenarios and maintaining regular upkeep, you can ensure your AC unit functions optimally, providing cool and comfortable air during the hottest months. If problems persist, always seek help from a qualified HVAC technician to diagnose and resolve the issue effectively.