On some air handlers, the condensation drainpipe has a little basic safety float change (see photo) connected to it. When the drainpipe backs up with water, the float switch will shut from the air conditioner. It is a sure sign that it’s time to apparent the condensation drainpipe. According to http://dominickesspr.blogerus.com/19541942/getting-my-best-heating-and-air-conditioning-to-work