QUESTION: “Can you help me figure out why my air conditioning condenser isn’t working?” Here are a few things to look at to walk through some steps a technician may use to fully diagnose a non-functioning air conditioning condenser.
Step-by-step guide to diagnosing a non-functioning air conditioning condenser:
- Disconnect power. First, make sure that the power to the air conditioning unit is turned off. This can be done at the main breaker panel as well as at the condenser disconnect box located by the condenser. Caution; electricity is dangerous and can kill you. If you are not 100% sure what you are doing, don’t guess. Get professional help. Turning off the power is for your own safety, as the condenser unit contains electrical components that can be dangerous to work on if the power is on.
- Visually inspect the condenser unit. Look for any obvious signs of damage, such as bent fins on the coils or a damaged fan blade. Also, make sure that there is nothing blocking the airflow through the unit, such as leaves or debris.
- Check the electrical components of the condenser unit using a multi-meter ( see ‘using a multi-meter‘ in next section ). Make sure that all wires are securely connected and that there is no visible damage to the wiring. Also, check the capacitor to see if it is swollen or leaking, as this can indicate that it has failed and needs to be replaced.
- Check the refrigerant levels in the system. This may require special tools and or professional expertise. The condenser unit will not function properly if the refrigerant levels are low. You can check the levels by looking at the pressure gauges on the system or by using a refrigerant leak detection kit.
- Check the thermostat. Make sure that the thermostat is set to “cool” and that the temperature setting is lower than the current room temperature. Also, check to see if the thermostat is receiving power and that the batteries are not dead.
- Check the air filters. Dirty air filters can restrict the airflow through the system and commonly cause the condenser unit to malfunction. Replace any dirty air filters with clean ones.
- If none of these steps have identified the problem, you may need to call a professional HVAC technician to diagnose and repair the issue.
Looking closer by using a multi-meter
If you are experienced with using a multi-meter, here are some additional diagnostic steps you can take using a multimeter to troubleshoot the electrical components of the air conditioning condenser unit:
Only proceed to the following steps IF ALL POWER IS OFF to the condenser.
- Set your multimeter to the “Ohms” setting. This setting is used to measure resistance in electrical circuits.
- Locate the compressor motor in the condenser unit. This is typically a large motor located at the bottom of the unit.
- Disconnect the wires leading to the compressor motor. There should be two or three wires, depending on the type of motor.
- Set the multimeter leads to the terminals on the compressor motor. The terminals are the metal posts where the wires are attached.
- Take a reading on the multimeter. A healthy compressor motor should have a reading of around 5-10 ohms. If the reading is significantly higher or lower than this range, the motor may be faulty and needs to be replaced.
- Repeat this process for the fan motor in the condenser unit. The fan motor is typically located at the top of the unit and is responsible for circulating air through the system.
- WARNING: Capacitators can HOLD A CHARGE WITHOUT the power being connected! Carefully check the capacitor. The capacitor is a small, cylindrical component that stores electrical charge and helps the compressor and fan motors start up. To test the capacitor, set the multimeter to the “microfarads” (μF) setting. Touch one lead to the “common” terminal on the capacitor and the other lead to the “hermetically sealed” terminal. The reading on the multimeter should be within 10% of the value printed on the capacitor. If the reading is significantly different, the capacitor may be faulty and needs to be replaced.
QUESTION: What are the most likely causes of an a/c condenser not working?
Common causes of a air conditioner not working.
There are several potential causes of an air conditioning (A/C) condenser not working properly:
- Clogged Air Filters – It may not seem obvious, but a dirty HVAC air filter can prevent proper function. Sometimes the thermostat or control panel will even display a code indicating this issue. Remove the air filter and hold it up to the light. Light should easily be seen. When in doubt, replace the old air filter with a fresh one.
- Electrical issues: The condenser unit contains several electrical components, such as the compressor motor, fan motor, and capacitor. If any of these components are faulty or not receiving sufficient power, the condenser may not function properly.
- Refrigerant issues: The condenser unit relies on a specific amount of refrigerant in order to function properly. If the refrigerant levels are too low, the condenser will not be able to cool the air effectively. On the other hand, if the refrigerant levels are too high, the condenser may freeze up and stop working.
- Physical damage: The condenser unit can be damaged by external factors, such as storms or debris. If the coils or fins on the condenser are bent or damaged, the unit will not function properly.
- Obstructions: If the airflow through the condenser is blocked by leaves, debris, or other objects, the unit will not work properly. The fins need to be unobstructed. Often years of dust can accumulate blocking free air flow across the fins. Grass clipping, dandelion seeds, leaves etc. all can accumulate and if the condenser fins is not regularly and carefully cleaned, the resulting clogged fins stop the air conditioner condenser from functioning properly.
- Thermostat issues: The thermostat is responsible for turning the A/C system on and off and maintaining the desired temperature. If the thermostat is not working properly, the condenser will not receive the necessary signals to turn on and off.