It was -6 showing this morning. Yesterday, I took the precaution of bringing equipment inside. Also, I opened the pump box up. I then stuffed some of that fibre glass matting (insulator) into a carrier bag, packed it around the pump, and screwed the box back up. The pump was working this morning whereas it froze up last week when the temperature wasn't quite as cold. Hopefully, my rather tacky looking solution was the answer.