Does water need to cover both sensors to start pumping water?
Normally, no. It depends on if the water is grounded. Looking at the bilge switch with the wires coming out the top, the lowest sensor disk becomes the activation sensor (on model 217,230, and 23 series only, Model 101 and 10 series only have one disk and use the mounting tab as a ground) so the water needs only to barely touch that sensor for 8 seconds to activate your pump. However, if your bilge water is not grounded the water may need to touch both sensors to activate the switch Note: In some cases where there is alot of rain water entering the bilge, the water may be too clean for our sensor to see. In these rare situations the best course of action is to manually activate the bilge pump to remove the rain water or add mineral (chlorine, salt, bilge cleaners) to the bilge.
Normally, no. It depends on if the water is grounded. Looking at the bilge switch with the wires coming out the top, the lowest sensor disk becomes the activation sensor so the water needs only to barely touch that sensor for 8 seconds to activate your pump. However, if your bilge water is not grounded or distilled water is used in the bilge, the water must also reach the upper sensor for 8 seconds to activate your pump.
