How to wire a condensate pump safety switch?
The correct wiring scheme for shutting down the AC completely is to break the 24v red wire (low voltage) coming from the t-stat bundle and then wire it in to the (COM) terminal of the pump. Then attach the second lead to the (RUN) terminal at the pump to the second red wire going to the control board/transformer.  The (ALARM) terminal of the pump is intended to attach an audible alarm device that would be tied into the red low voltage t-stat wire. The previous wiring scheme will also work but only shuts down the outside unit's compressor, however the fan will continue to run.