Nordyne Furnace Model: kg7sc-072d-24b The furnace runs a few hours normally. (normal cycle) And then keeps running short cycle (about 10 seconds)( ignitor red->flame on->before the blower starts, gas shut off; never stops. (no one hour lock out?) After certain time (one hour or so?) then runs normally again. This repeats again and again. Where is the possiable problem? (new control board, new ignitor, new flame sensor, new filter)