I installed the Noma 52-2570-6 programmable thermostat in 2009 no problem after that but yesterday I change the batteries for the 1st time & did a hard reset but after that heat won't shut off even in OFF mode I have set around 21C but furnace keep running on 28C. I have change option Cr-4 to Cr 0 & 1 but to no avail. Please advise what could be the problem?

Thanks