Has The Honeywell YTH9421C1010 Been Discontinued?
As of April 14, 2015 the manufacturer discontinued the Honeywell YTH9421C1010 thermostat. It was first introduced March 30, 2009 and quickly became a very popular thermostat. The YTH9421C1010 was what they call a communicating thermostat. Communicating thermostats can operate with fewer wires and are proprietary, meaning that they are the only thermostat which can be…