Action Air & Electric Inc

Our a/c stopped working and we called action air and electric who installed it for us 3 years earlier. when they came they found a leak in a pipe, patched it and replaced the coolant for close to $600. the a/c worked for 1 day then died again. we called action air again and they came out to replace the pipe this time. 89 days later the a/c has stopped working again and once again we called action air cause it has a 90 day warranty. When we mentioned the warranty to action air they told us that it is probably not the same issue. How on earth can they know it is probably not the same issue over the phone when they have not even come back to look at the a/c.