Air conditioning plays a key role in maintaining comfortable temperatures within residential buildings and office spaces, especially during the hotter summer months in Houston. Just like any other man-made device, air conditioning units can break down.

We sometimes get calls about the failure of the outdoor A/C component while the internal fan runs but fails to cool the space it services.

My Outside A/C Won’t Turn On, but It’s Running Inside

This is one of the most cited complaints by homeowners concerning their air conditioning units. The terms “outside” and “inside” A/C is not technically accurate, but it’s easy to understand what a homeowner or office manager means by this terminology.

What Is an “Outside A/C Unit” Actually Called?

An “outside A/C unit” refers to the condensing unit of the air conditioner. The condenser is made up of important two parts, a compressor, and a fan.

When operating properly, refrigerant within the condenser coils is compressed and cooled below its core temperature. The chilled refrigerant is then driven through another set of coils in the indoor evaporator unit where heat exchange occurs, and the heated refrigerant is circulated back to the condenser. The overall effect of this cycle is the cooling of the air within a supplied space/room.

9 Common Causes of an Outside A/C Unit Not Running

In some cases, the outdoor A/C unit will fail, causing an incomplete air conditioning cycle. Outlined below are nine of the most common reasons for outside A/C unit failure.

1. Refrigerant Issues

A condenser/compressor that has developed a refrigerant leak will eventually fail when it has lost a significant portion of its coolant. Refrigerant shortages from leaky condenser coils will effectively shut down the outside unit of an air conditioning unit as the medium for heat exchange within an inside evaporator unit is lost.

2. Tripped Breaker for Condenser

Outdoor condenser units usually have circuit breakers that control the power supply to their components. Unfavorable operating conditions will trip these circuit breakers cutting off the power supply to the outdoor units and prevent them from compressing the refrigerant used in air cooling.

If you flip your breaker on and find out that your condenser begins to run again, you’re not out of the woods yet. Tripped breakers are usually caused by an underlying condenser issue that drew too much power to the system. Schedule a service call with a local HVAC technician to prevent this issue from reoccurring or causing permanent damage.

3. Blown Fuses

Sudden power surges during adverse operating conditions might cause the fuses within an outside A/C unit to blow. This protects its components from electrical damage but effectively renders the unit inactive till the blown fuses are replaced.

4. Faulty Condenser Compressor

A/C won't turn on

Another factor causing external A/C unit failure is a faulty compressor. The effectiveness of a defective compressor unit will progressively decline until it is unable to sustain any refrigerant compression/cooling and must be replaced either in part or whole.

5. Faulty Condenser Fan

A condenser’s fan is supposed to blow air over its coils to help cool the refrigerant contents from a gas into a liquid state. When a condenser fan fails due to a defective motor, the entire compressor unit will overheat and shutdown from the resulting thermal damage.

6. Wiring Issues

Most split-unit air conditioners have an extensive network of wires connecting their different components. Some of this wiring is located on the building exterior and exposed to the elements. Over time, these wires will erode and break down. The resulting disconnect will shut down the external compressor unit.

7. Thermostat Malfunction

A/C won't kick on

Thermostat malfunctions are common in air-conditioning units that possess analog thermostats. These older thermostat units are less accurate at detecting thermal changes within the space being cooled resulting in a less than perfect air conditioning experience.

Newer digital thermostats are more responsive to temperature changes and less likely to negatively affect an outside A/C unit’s function. However, they are not immune to the occasional malfunction.

8. Emergency Shut-Off Switch Flipped

Similar to the idea of a circuit breaker, most air conditioning units possess an emergency shut-off switch that can be flipped to cut off power to the A/C unit. This switch can be purposely turned off during unit repairs but can also be switched off by accident during yard work, etc.

9. Clogged Condenser Drain Line

As a safety feature, some air conditioning units will automatically stop working if their drain lines become clogged. Without unclogging drainpipes, the A/C unit will fail to restart. Ideally, drain clearance should be done by a professional A/C technician to avoid making the problem worse.

Who to Call When Your Central A/C Won’t Turn on In Houston

If your air conditioning unit has developed any of the above problems, we recommend that you contact a professional HVAC technician to take a look at it. If you’re based in Houston, URETEK is your best bet!

Trust URETEK Gulf Coast with Your Air Condition Repair

At URETEK Gulf Coast, we offer expert A/C repair in Houston aimed at optimizing your home cooling experience. Our licensed and highly skilled technicians will ensure that your A/C unit gets the appropriate system diagnosis and maintenance. We also offer robust air conditioning replacement in Houston for units that are beyond fixing.

Contact us today for an estimate if you’re based in Houston and need the help of an HVAC professional.