When your air conditioner stops blowing cold air, it may be time to replace your evaporator coil. Some technicians charge anywhere from $800 to $1,500 to do this.
While we suggest hiring a professional to replace evaporator coils, here's an idea of what you can expect, if you want to try it yourself.
Park any remaining Freon in your air compressor. Turn off the liquid line at the air compressor, and switch the gauge to low before changing your ac evaporator coil.
Cut off compressor. This is a tricky step when changing your HVAC evaporator coil, and it's best to have an extra pair of hands to help out. When the pressure reaches zero, shut the valve off on the low side. Cut off the compressor right away. If you run the compressor with no incoming gas, you'll burn it out.
Cut tubing. Next, cut the lines which lead from the compressor to the air conditioner evaporator coil with a tubing cutter.
Remove the old evaporator coil.
Install new evaporator coil. Slide in the new evaporator coil. Try not to over handle it.
Braze the lines. Braze the lines back together by soldering.
Don't open the lines back up. Pull a vacuum on the side of the compressor shut off valve that is open to the condenser.
Determine if there are leaks in the system. Turn off the vacuum, and check the levels. If it steady for ten or fifteen minutes, then you're fine. If it kind of moves around, then you will need to run the vacuum one more time.
Close valve gauges. In order for your system to maintain its vacuum, you need to close the valve gauges to the vacuum pump.
Restart the system. Open up the liquid line, and the open the gas line which goes to the compressor, and let them work for about ten minutes. Restart the system.
Don't purge the system. Most people think you have to do this, but you don't. There is no way to single out the Freon, so you're good to go! Remember, check evaporator coil prices prior to taking on this project yourself.