Every Air Conditioner Has A Life Span
The idea life span of an aircon unit can be anywhere between 10-15 years, as long as it is cared for properly. An aircon system needs regular maintenance checks in order to continue functioning efficiently.
Aircon Unit Is On But No Air Blowing
- Fan and Fan Motor
If your air conditioner is not blowing any air, the problem could be the fan or fan motor. In a properly working air conditioner, the fan will draw air over the cold evaporator coils and then re-circulate the air back into the room. If the circulating fan is not running or running too slow, little or no air flow over the evaporator coils will allow them to become too cold and frost or ice can form, restricting the air flow even more. The fan and motor are located inside the cabinet so removal of the cover will be necessary to perform any checks. Make sure that the fan motor will turn easily and that the blades are not damaged. If the motor is seized or if the fan blades are damaged then they will need to be replaced. If the motor turns easily it may still be defective or it may not be getting power from the controls. These tests are more complicated and should be performed by a qualified person who is comfortable with the use of a multi-meter.
- Fan Motor Capacitor
Most window air conditioners utilize a run capacitor in the fan motor circuit. If the motor hums or turns slowly you may have a defective capacitor. The fan motor and capacitor are located inside the cabinet and access will require removal of the cover. Verify that the motor and fan can turn freely and check for any burnt or damaged wiring to the motor and capacitor. If the capacitor does not show any visible signs of damage you will require a qualified person to check it with special test equipment.
- Electronic Control Board or PCB Assembly
If your air conditioner is running but not blowing any air and you have inspected the air filter and fan motor and found them okay, then you may have a problem with the control board. Sometimes referred to as the PCB, this is an electronic control board that operates the fan motor and compressor circuits using relays mounted on the circuit board. The power output from the relays can be checked with a multi-meter, but this should only be attempted by a qualified person. If the on board relay is defective, or if the processor circuitry is defective then the control board or PCB will need to be replaced.
Aircon Unit Does Not Blow Cold Air
- Temperature Control
If your air conditioner is not blowing cold air and you have inspected the air filter and fan motor and found them okay, then you may have a problem with the temperature control or thermostat. This is the device that monitors the incoming air temperature and turns the compressor on or off. There is normally a sensing bulb attached to the control that will extend to the front of the evaporator coil, and a set of electrical contacts in the body of the control that supply power to the compressor circuit. The bulb monitors the room air temperature and will tell the thermostat control to turn the compressor on when the set temperature is lower than the room temperature. The thermostat will also cycle the compressor off when the desired temperature has been reached. If the temperature control or thermostat is defective, it may not send power to the compressor, and no cooling will take place. Inspect the sensing bulb for any signs of a sharp bend, kink or rupture and replace the control if any are found. You can also check the continuity of the control with a multi-meter by rotating the dial to the lowest setting. Verify that the sensing bulb is properly located in the air flow through the evaporator coils before condemning the control.
If your air conditioner doesn’t blow cold air, the problem may be in the compressor circuit. Most air conditioners use a capacitor to help start the compressor. If the capacitor fails, the compressor won’t start and the fan will only blow warm air. Some air conditioners utilize a run capacitor in the fan motor circuit as well and will often combine both devices in the same package or can. The compressor and capacitor are located inside the cabinet and access will require removal of the cover. If the capacitor does not show any visible signs of damage you will require a qualified person to check it with special test equipment. Make sure that the replacement capacitor has the same specifications as the original.
If your air conditioner is not blowing cold air and you have inspected the air filter and fan motor and found them okay, then you may have a problem with the thermistor. This component is found on electronic control models and monitors the incoming air temperature and signals the main control board to turn the compressor on or off. The device is normally located in the air flow near the evaporator coil. If the thermistor is defective, it will not provide the proper signal for the control board to turn the compressor circuit on. Replace the thermistor if there are any signs of damage or corrosion.
Aircon Unit Does Not Turn On
- Electronic Control Board or PCB Assembly
Refer To Similar Above
- Thermostat or Temperature Control
If your air conditioner has a rotary type temperature control or thermostat and does not turn on you may have a defective control. The thermostat control uses a sensor bulb to monitor room air temperature which in turn operates a set of enclosed electrical contacts to supply power to the compressor circuit. The thermostat control senses the room air temperature and turns the compressor circuit on until the set temperature has been reached. Verify that you have power getting to the unit or if your model has an Energy Saver or Fan Only function, verify that the fan will turn on. As you rotate the temperature control or thermostat to a colder temperature setting you should hear a click sound indicating that the contacts close. You can check the thermostat for continuity with a multi-meter as well.
- Power Cord
If your window air conditioner won’t turn on, it may be that it is not getting any power. Check the receptacle with a tester or plug in a known working appliance such as a lamp or a fan to verify that the circuit is live. Check the air conditioner power supply cord for any signs of fraying or damage. Newer model units often have a built in circuit breaker in the supply cord, so check to see if that has tripped. If the supply cord appears to be undamaged you can remove the cabinet and with a multi-meter, check the terminal strip where the cord attaches, to verify that you have proper voltage. You should never attempt to repair or modify the supply cord but replace any that you find defective
- Thermistor or Temperature Sensor
Modern window air conditioners often use an Electronic Control Board, sometimes referred to as the PCB, to control the functions of the individual components of the unit. A sensor device called a thermistor is mounted near the front of the evaporator and is used to monitor the room air temperature. This information is sent to the control board where it is processed and used to cycle the compressor on and off to maintain the set temperature. If your air conditioner won’t turn on, you may have a defective temperature sensor. Testing of the sensor will require the technical specifications of the thermistor for your model and a multi-meter. Inspect the control board for any signs of a loose connection to the sensor as well.
Modern window air conditioners that use an Electronic Control often have an internal fuse for protection. If your window air conditioner won’t turn on, it may be that the fuse has blown. First verify that you are getting power to the unit and then unplug the unit and remove the cover. Locate the circuit board and check for a removable fuse. If one is found, look for signs that it has blown or use a multi-meter to check it. If the fuse has blown, replace it only with the proper type and rating.
- Fan and blower wheel
If your window air conditioner is making an unusual noise, the problem could be with the fan. In a properly working air conditioner, the motorized fan will pull air through the filter and over the cold evaporator coils and then re-circulate the cooled air back into the room. There is also a second fan on the motor shaft that cools the condenser coils at the back. If either fan blade is bent, damaged or has an accumulated dirt build-up on them that may cause an unbalance, they might make an unusual noise. Remove the cover and inspect the fan blades for any signs that they may be contacting the cabinet, fan housing or insulation and adjust if necessary. Remove any foreign objects that may have entered the cabinet and could be contacting the fan blades. If the blades are very dirty then you should also clean the evaporator and condensers coils and clean or replace the filter at the same time. Verify that the fan blades are not damaged or warped and that they are attached securely to the motor shaft and tighten or replace as necessary. On some models the condenser fan blade is also used to sling the condensate or drain water onto the condenser coils to increase the efficiency of the unit. If the unit is not installed properly or if the drain port is plugged or restricted, then there may be excessive water in the bottom of the unit causing a loud or unusual noise as the fan blade makes contact with it. Clear the obstruction or tilt the unit back to correct the symptom.
- Fan Bearing
Most air conditioners use a double shaft fan motor with two fan blades, but some air conditioners use a squirrel cage style of blower wheel. If you have this style of fan and it is making an unusual noise, you may have a defective blower wheel/fan bearing. This type of blower normally has a drive motor attached to one end and is fitted into a stationary bearing at the opposite end. You will need to remove the cover to access the fan assembly. Detach the motor and blower wheel from the bearing to allow for easier replacement.
- Fan Motor
Window air conditioners normally use a double shaft fan motor with two separate blades attached. One blade is used for drawing air over the cold evaporator coil and re-circulating it into the room. The opposite end of the motor has a fan blade that is used to dissipate the heat from the condenser coil. When your air conditioner is on, the fan motor runs almost continually, and over time the motor bearings or bushings may wear out and develop an unusual squeaking, screeching or roaring noise. If the air filter is not cleaned or changed regularly, or in unusually dirty environments, the fan blades can accumulate dirt and become unbalanced which can cause premature wear to the motor. Most models use non serviceable motors and when they become noisy, they will need to be replaced. Verify that the fan blades are not damaged as well and replace them if necessary
- Spring Clamp
If your window air conditioner is making an unusual noise, the problem could be that one of the fan blades is loose. In most window air conditioners, there are two fan blades attached to the fan motor. One of the fan blades is used to draw air through the evaporator coil and to re-circulate the cooled air into the room. The other fan blade is used to help dissipate the heat from the condenser coil at the back. Both blades are attached to a double shaft fan motor and are often attached to the shaft with a spring type clamp. If the clamp is weak or damaged, it may not hold the hub of the fan blade securely to the motor shaft and the blade may wobble and vibrate creating an unusual noise. Remove the cabinet and check the clamps for a secure fit. Check the hub of the fan blade for any signs of damage as well and replace if necessary.
Hiring a Professional
When your air conditioner needs more than regular maintenance, hire a professional aircon service technician. Our well-trained aircon technician will find and fix problems in your air conditioning system.