Concord 80 gas furnace
 

i have a Concord 80 Plus Gas Furnace that is malfunctioning. It seems to reach room tempature and shuts off. and doesnt restart. I have to manually lower the temp on the thermostat till the thermostat clicks then turn the temp back up and the furnace will start. run for several minute warm the house nicely then shuts off and wont start again.

any thoughts on what might be the problem? the indicator light on the furnace blinks 6 times what ever that means

A sticking thermostat?

A number of things could be wrong. Sensor, hi-limit lock out..

Need more info . model and serial would help.

A lot of older Concords had a Smart Valve that always failed as you describe.

Model: CG80UA100D14B-1
Serial #: S1601L15777

does this have a pilot type igniter?http://www.allpartsheating.com/_imag...acment-sth.jpg

And does it have a valve like this?http://ecx.images-amazon.com/images/...500_AA300_.jpg