Our system controls both the central air and heat in our home (which is a rental). Yesteday I noticed that after I had switched on the heat that the thermostat was no longer working. We have checked all the breakers and examined the circuit board, however, I am still in a quandry if this is a battery issue or if I should just call the rental management office back and have them send their professional ttech. Team over. The house is single family and only 4 years old and the a/c worked fine all summer. Any insight?

I would try changing the batteries