I had the thermocouple replaced last winter.. it worked for about 3 months then went out so I thought.we left heater off for the rest of the winter and just used space heaters.this year I went to clean heater pads and dust.so I thought I would give it a shot at lighting the heater to see what was going on and to my surprise the heater started right up for about 2 weeks.is the problem my thermocouple or my lever that has off on and pilot and set??