Air Handler Not Working But Outside Unit Is

If your outdoor condensing unit is working but your indoor unit isn’t, it can be frustrating. The indoor and outdoor units work together to heat and cool your home. Until one day, the unit stops working. Learn why this is happening.

If the air handler is not turning on at all, there are several possible causes. What is causing the problem will dictate the solution.

Check to make sure there is power to the unit. Some air handlers have what looks like a light switch next to them. Make sure it is in the ON position. Check the circuit breaker box to see if the breaker has tripped. If it has, call for HVAC repair. A problem with your system may have caused the breaker to trip. Turning your system back on without resolving the problem could result in damage.

When was the last time you changed the air filter? Can’t remember? Go check it now and replace it if it’s dirty. A clogged or dirty air filter can cause the unit to overheat and shut down as a safety measure.

Look at the air handler. Is there visible frosting on the cabinet or water dripping? You may have a frozen evaporator coil. Turn the HVAC system off at the thermostat and call for HVAC repair.

In addition to the evaporator coil, the indoor air handler contains a blower motor and a blower fan. The motor has a run capacitor to help it run smoothly. If the capacitor is bad, the blower motor won’t run, and the fan won’t blow conditioned air throughout your home. You’ll need an HVAC technician to troubleshoot the issue.

Another possible reason your air handler is not working but the outside unit could be that the air handler blower motor has failed. An HVAC technician will be able to determine if this is the problem.

Finally, there could be a problem with the air handler’s control board. It may have a minor issue, or it may have failed. A trained HVAC technician can determine if the control board is the culprit.

Depending on the repair cost estimates and how old your air handler is, you’ll need to consider whether repairing the unit makes financial sense or if it’s time to replace your HVAC system. Our Repair or Replace Guide can help you make that decision.

Anne Fonda, Content Writer at Trane Technologies

A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.

She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism. When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.

Expert review by Kimberly Sexton, Senior Systems Engineer

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