the alarm is continually going off. i have unplugged the unit for five minutes as requested by manufactuer. still goes off in the middle of the night. temps are 0 and 37. the high temp light is on. why after only three years old is the problem occuring? also, i called repairman and was told sensors or control board? can i get the sensors myself and try that first? without going to the expense of huge money to replace board? thanks. i will be anxiously awaiting your response. scott