I found corrosion products on my thermostat battery/terminals. Took out old battery and cleaned terminals. Put in new battery. Now it does not work. No heat and fan keeps on running. I pressed reset button, still does not work. It's cold, and with the fan ruuning and no heat on, the house is losing heat even faster. Help support is closed now - weekend. I need help fast. Thank you.

Need to know more about the system-gas furnace and/or heat pump, brand and model # would all be helpful.