You turn on an HVAC fan. Nothing happens. You turn the fan from “Auto” to “On” and still nothing. Or maybe it’s hot in Winchester, and the AC isn’t cold enough. 

This is perhaps the most frustrating and alarming thing that can happen to any homeowner. Before going into a panic and assume you are looking at thousands of dollars for repairs or replacements, let’s consider the fans.

Many times there are cooling problems, it is on account of an HVAC fan not working. 

Many times when cooling problems begin, the HVAC fan is to blameWhat’s Happening? 

Any sort of troubleshooting process can be frustrating, especially if you don’t know what you’re looking for. Sometimes you’ll get lucky, and the issue jumps right out at you, but you can’t depend on this being the case. 

If a fan isn’t working, there are a few quick steps you can take to pinpoint the issue. 

Be mindful that dealing with electrical components and moving parts of an HVAC system is dangerous, even if you know what you are doing. Only approach the process if you are comfortable with doing so. Otherwise, calling for professional HVAC help is highly recommended.

Blower Motor Fan not Working 

If the fan isn’t coming on even when you set it to the “on” position, it’s time to start troubleshooting. The root of the issue can be addressed, but you may need to call for professional help. This depends on your level of experience and comfort in dealing with the blower motor and electrical systems.

Tripped Breaker

If the fan isn’t turning on, it may be on account of a tripped breaker. Before moving to the blower motor itself, check to make sure there is power being supplied.

Bad/Seized Bearings

If the bearings inside the fan are shot, the fan may need more effort to spin, if even possible. To see that the fan can rotate freely, you will want to turn the power off to the unit and see that you can move the fan. If not, or if it takes a lot of effort to do so, the blower motor fan will need to be replaced.

Faulty Wire Connections

The system operates on electricity. Any faulty connections will prevent the fan from running. If you find any disconnects be sure that no power supply and that the capacitor has been discharged.  

Bad Capacitor

The capacitor is needed to hold a charge, which is essential to run the fan. If you are comfortable and familiar with testing this unit, you can do so but may want to call for professional help.

Bad Control Board

The fan may not be coming on due to a bad control board. With the fan on, check to see that power is being supplied to the appropriate contacts. This process generally requires professional help.  

Bad Fan Motor

If all else checks out, there’s a chance the fan needs to be replaced. These motors see a lot of abuse, and over time they will fail. If the motor is faulty, it may be time to replace the entire unit.

AC Condenser and Compressor Fan Not Working 

If air is physically moving through your home, but it’s not cold, chances are the fan on the Central air conditioner condenser unit is the problem. This fan is necessary to cool air as it blows hot air away from the condenser coils, which is needed to bring refrigerant back to a liquid state. 

There may be a few reasons why the fan isn’t working. As always, start with the easiest to address and work your way through the list.

  • Tripped Breaker:  Before opening up the AC condenser unit, check the breaker. If it has tripped, no power is being supplied to the fan and can be addressed immediately. 
  • Blown Disconnect: Before proceeding, check to make sure no fuses are blown in the system disconnect. If blown fuses are present, it is indicative of more serious issues that warrant professional help. 
  • Faulty Wire Connections: Just like the blower motor, electrical connections are necessary for the fan to function. Before attempting to reconnect any wires, be sure there is no power being supplied to the system and that no components, namely the capacitor, are holding a charge.
  • Bad Belt: If you are running an older system, the fan may be belt-driven. If the belt is worn or broken, it will need to be replaced.
  • Bad Capacitor:  The capacitor is a means of stored power. Over time, a capacitor may lose the ability to hold a charge. You can test to make sure enough energy is present but may want to call a professional.
  • Bad Contactor: The contactor primarily functions as a switch to control the fan. Over time, the contacts can fail. If this unit fails, it will need to be professionally replaced.
  • Bad Fan Motor: The fan motor may have burnt up over time. If all other areas check out, this may be the case. If the fan motor is burnt up, it will need to be replaced. It may also be an indication that it’s time to replace the entire unit.

Concluding Thoughts

As mentioned, any troubleshooting should only be done if you are experienced and comfortable enough to deal with electrical systems and moving parts. 

Safety is essential here as there is a dangerous level of power in these components, and there’s no room for mistakes. If you are comfortable enough, take your time and follow the troubleshooting procedure above.