The answer to 'my air handler keeps shutting off' is the air handler is likely overheating and automatically shutting down to prevent damage. This can be caused by a few common issues like a clogged air filter, low refrigerant levels, or a problem with the blower motor or compressor.
Some key symptoms to look for are the air handler repeatedly turning on and off, warm air coming from the vents, or the system not cooling your home effectively. To troubleshoot, first check and replace the air filter if it's dirty. If that doesn't fix the issue, you may have a refrigerant leak or a problem with the blower or compressor that will require a professional HVAC technician to diagnose and repair.