I have a high water table that caused theLiberty Pumps 287 1/2-Horse Power 1-1/2-Inch Discharge 280-Series Automatic Submersible Sump Pump with VMF Switch to run every few minutes, even during dry weather (2008 house has 9' ceiling basement & is very close to a reservoir). Since the basement had flooded by several inches during 2011's Hurricane Irene during a blackout (prior to my purchase of the home), I was paranoid about ground water. Additionally, the previous owner had to replace the sump pump after only 3 years, so I wanted to minimize the on/off cycle, which not only is bad for the sump pump, but is annoying (constant on/off whirl heard from the main floor) and a waste of electricity. I first boughtGlentronics, Inc. BWC1 Basement Watchdog Dual Float Sump Pump Switch with Controller to "raise" the water level switch. Installation for this piggyback switch was easy: 1. Plug the sump pump power plug into the back of the this device's power plug, then plug it into the wall power outlet. Note that the power plug is quite large in all dimensions, but it stayed put and didn't lean out at all. 2. Using the supplied metal ring and flat-head screw, tie the float along the sump pipe at the appropriate height, determined by your water table during a dry week. Note that ground water can still persist for days after a rain had stopped. 3. Test by lifting the bottom of the float with your finger or screw driver (or dump water into the sump pit). Using the Watchdog to "raise" the pump activation trigger--to about 2" below the basement surface--cut the sump pump activation to occur only every few hours, which was indeed an improvement. The switch reliably activated the pump. However, the switch was supposed to continue to electrify the plug's outlet for at least 10 seconds upon activation to ensure sufficient water has been pumped out, but mine only went on for a few seconds after water level receded below its float (often for a begin-end cycle of only ~5 seconds). The pump itself would have turned off upon its own float switch hitting bottom, but there was plenty of water still left during these early shutoffs. Manually lifting the Watchdog's float switch with a screwdriver would indeed activate the pump until the entire pit was empty. I later had installed a second pit and (Zoeller 98-0001 115-Volt 1/2 Horse Power Model M98 Flow-Mate Automatic Cast Iron Single Phase Submersible Sump/Effluent Pump ) with another Watchdog (on separate, dedicated 15A outlet/circuit/fuse), but it had the same issue of turning off too early. After several months of looking for a better solution and much gnashing of teeth, I bought 2 ofLittle Giant RVMS-10 1/2 HP Piggyback Vertical Mechanical Float Switch , which are basically the same idea and installed the same way. The RVMS goes deeper into the pit since it's basically a long stick with a purely mechanical on/off float switch, but you can trim the stick's depth as needed. It also reliably pumps the desired depth of water for the expected duration (the depth of the float's stick: ~6.5"). We now go days without any water pumping. --- FYI, I additionally had installedLiberty Pumps SJ10 1-1/2-Inch Discharge SumpJet Water Powered Back-Up Pump for each of the 2 sump pits in case of pump failure or blackouts. No batteries to maintain or replace, and no time limit during extended blackouts. Only requirement is sufficient water pressure (I believe ~30 PSI; I actually needed the plumber to lower mine from "dangerous" 65 PSI). Also, You may want to consider also purchasing water alarms like BWD-HWA (takes a 9V battery), which will alert you if there's contact with water (e.g., sump pump failed). I also have these alarms around the house (under the sinks, behind the laundry, by a/c handlers, etc.), and they've proven very worthy (sump pump didn't run during a night blackout and water reached a threshold just under the water-powered pumps; laundry unknowingly had leaked when using jumbo load size). They'll pay for themselves in minutes vs water damage repairs.
