I have a new honeywell thermosat rth2310 and the

Did you just install it????? If not check the batteries and replace them first....check for corroding also....if you just replaced the thermostat did you wire it correctly????/Wire for Wire???? If so if you have 4 wires in your thermostat you require a jumper wire between RH & RC....if you have 5 wires...no jumper is required....is the Furnace power on???