I checked the water heater circuit breaker and sure enough, it was off. Since this elderly lady was alone, I also did a little maintenance on the exterior insulation and did a complete check-up on the system. All is working fine. Controller, pump, sensors, etc. Repaired severely deteriorating insulation. (Noticed that insects had built nests within controller enclosure box. Cleaned out. Somewhat common in some utility rooms.) Will probably need a new air vent and freeze valve within 2-5 years.