Secondary drain pans should NEVER have water in them. Never, ever, ever. That's why you install the float switch in a place where the condensate will pool FIRST to stop the system when something's wrong. Our latest video covers HVAC drain line installation and troubleshooting. You can watch the full video with more tips and best practices at https://buff.ly/qIzkZLY. | HVAC School

Clogged Drain! One of the most important things for a homeowner to know is where the secondary AC drain line is. This drain line should not have water coming from it. It is usually located over a window. That way if water comes out of it you can see it. When water is coming out of this pipe, that means water is going into the pan. If you have a float switch installed, the unit will turn off when the pan gets a certain level of water in it, if you don’t, water will go over the pan and into the ho