I have Tappen electric central a/c unit , non-programmable Robertshaw digital thermostat and a Tappen condenser unit, all about 6 years old. The recent problem I'm been having for about 3 winters now is that the unit will try to turn on the heat when the house gets cold even if the thermostat is set to "off". I was wondering if anyone else has had this problem and if it's a simple fix? The heater works, shorts cycles a bit the first few hours of use, then works great the rest of the season.