Our Carrier Comfort Zone II thermostat, which has 2 zone readouts, currently shows a temperature of 00, as in zero zero, on one zone. That is the main zone for our home. Zone 2, for spare bedrooms, etc. shows the proper temp. An additional smaller Carrier thermostat for our master bedroom zone, (zone 3), also shows correct temp. I have fiddled with the overly complex settings, and I am at a loss to get the "zero-zero" temp reading back to "normal" in the Zone1 display of ambient temp. We are a long way away from any competent Carrier service people, or even competent HVAC company in general. Unit is 9 years old, but is only used when occupied, aprox 7 months per year. Any ideas or fixes? Thank you, David