The AG-3150E electronic water sensing system is the only condensate sensor that plugs into the auxiliary drain port of the primary pan and qualifies as an internal primary pan sensor, monitoring condensate directly inside of the primary drain pan. The AG-3150E is a high-amperage, solid-state switch with no moving parts to break down or become clogged and the low profile design makes it easy to install and does not interfere with drain lines coming from the HVAC unit.