Has anyone ever blown a fuse that connects the control board to the loop pump? This caused a waterflow red indicator light and a low pressure indicator light and the system went into Aux mode. The system experienced a freeze condition when the thermistor detected the temperature drop due to no waterflow. I have had the system, a Waterfurnace Premier, for 8 years and never experienced any kind of issue before. My HVAC tech came out, traced the blown fuse, and replaced it. System has been heating fine since fixed a few weeks ago. I am curious what would have caused this? Do these fuses just wear out?