Outside Unit Not Coming On
Your AC Won’t Cool Without the Outside Unit — Here’s Why
Ever notice your AC running but your house still feels warm? You hear the indoor fan blowing, but there’s no cold air coming through the vents. In many cases, the culprit is the outside unit — also known as the condenser — failing to turn on.
This outdoor component is essential to your air conditioning system. Without it, your system can’t remove heat from your home, which means no matter how long the indoor fan runs, the air won't cool down.
If you rely on a heat pump, the stakes are even higher. When the outdoor unit isn’t working, you lose not only cooling but also your primary source of heating. Sure, most heat pumps have a backup heat strip system, but that emergency heat is expensive to run and far less efficient.
In this post, we’ll break down the most common reasons your outdoor AC unit might not be engaging, what signs to watch for, and what you can safely check yourself before calling in the pros.
Let’s get started.
Common Reasons Your Outside Unit Won't Come On
Anytime your outside unit won't startup, there are a number of potential causes. Understanding why your condenser may not be starting can help you sometimes solve the problem yourself, or at least identify when you should call a professional.
Faulty Capacitor
A capacitor delivers and initial burst of energy to start up your motor and compressor. Without it your unit cannot start. For do-it-yourself homeowners, changing a capacitor is not out of the question, but be careful. To change the capacitor you'll be exposed to electricity as well as the risk of causing further damage to your unit if you wire things back incorrectly.
Identifying this issue will take a little more technical knowledge and the ability to use a meter. Unless you are familiar with capacitors and electricity, this likely requires a professional. If you do attempt this, please keep in mind that this is a high-voltage component and is very dangerous. Do not attempt this repair without the proper tools and experience.
Bad Breaker
Sometimes the reason your outside unit is not coming on is because your breaker is tripped. A breaker can trip for several reasons leaving your air conditioner without power. Oftentimes you can flip the breaker back on and resume normal operations, but that doesn't mean the problem is fixed. Anytime a breaker trips it has done so for a reason. This could indicate an issue with your breaker or possibly an issue with your air conditioner.
Take a minute to check all of your breakers. There is often one immediately beside the outside condenser as well as near your main outside panel. In some cases, you will also find a breaker inside of the home tied to your condenser.
Wiring Issues
Frayed or burnt wires can cause an outside air conditioner to not run. There are a number of reasons why an outside AC may have damaged wires, such as external forces damaging the unit or an overload in the circuit. As this occurs, many wires can be repaired or replaced, but that sometimes doesn't solve your underlying problem. If your compressor or motor is drawing too much power, which could be the cause of your overload, this may indicate that part is failing and will need to be replaced soon.
Doing a visual inspection of your system can identify wiring issues. If you see any visible damage to wires, that's likely the cause of your problem.
Failing Compressor
Your compressor is the heart of your HVAC system. It pumps the coolant through the lines which is essential to the cooling process (and heating process with heat pumps). When your compressor won't come on your outside unit won't work. In many cases this issue can be resolved easily, but oftentimes it requires a completely new compressor being installed.
Strange noises and simply its failure to start is a good indicator that the compressor is having an issue. To confirm this diagnosis, you will need to contact a professional HVAC technician to inspect it.
Other Components
Besides what we have mentioned already, there are other components inside your condenser that can fail and keep it from running. Most of these, like the control board, will require advanced technical knowledge to diagnose and replace.
Is Your Outside Unit Not Coming On?
If your outside unit is not coming on, we understand how important it is to get it fixed fast. That's why we're standing by 24/7 to assist with any HVAC repairs or maintenance you may need. We can perform your semi-annually required maintenance as well as help with the proper landscaping around your air conditioner to keep your unit protected against the elements and highly efficient.