I have a Cozy wall gas furnace - it looks new. Sometimes it starts and sometimes it doesn't. The first thing I did was replace the thermostat with an electronic one. Same problem. To get the furnace to start I bang on it - I know it sounds silly, but it works. Maybe there is a loose wire in the furnace ? Or possiblity the vibration of the banging is tripping a sensor? Any direction is appreciated - thanks
-tomas