My maple chase thermostat shows low batteriy I changed the batteries, checked for corrosion and even changed the fuse. I am still getting low battery. Please advise on what to do

I hate to say it (well, not really... ) but you may be in the market for a new thermostat. Maple Chase, Hunter, and Rite-Temp thermostats are prone to failure. Purchase a Honeywell or White-Rodgers replacement.