This pump includes some debris and ice overload protection for added safety, but you shouldn't rely on that. When temperatures drop below freezing, you should remove the pump from service and store it indoors to protect it from ice damage. The pump has a unique protection circuit to protect the motor from a locked impeller condition possibly caused by debris buildup or from a “frozen” impeller situation caused by ice formation. When the pump is activated and a locked impeller condition is detected, the unit will automatically shut down to protect the motor from overheating. The pump will continue this on/off cycle for a period of time to attempt to “free” the impeller until eventually the unit will remain off for a period of 12 hours checking twice a day for a “freed” impeller. Once the pump is able to operate correctly, the pump will resume normal operation. To reset this delay without waiting 12 hours, momentarily unplug the pump.