Water heater. Bradley White. Three yearsvold. A heavy snowfall last year covered the outside pipe and the system shut down till I cleared away the snow. This year iti is bitterly cold (-30F). The pipe is clear of snow but screen was quite frosted up. Will clearing fix it? Shoud I unplug and then plug in the power cord above the unit to reset? Is the green light supposed to be flashing or constant green if the unit is working? Thanks!