Float switch R-wire cutoff stops HVAC water damage A float switch installed in the HVAC condensate pan can cut power to the R wire and prevent system operation when water overflow or a clogged drain is detected, reducing the risk of water damage and mold. Learn how to wire a normally closed low voltage float switch into the R lead, test the device with a multimeter, and verify shutdown by pouring water into the pan so the switch trips. This guide covers condensate overflow protection, HVAC safet