This is a very intermittent problem. Thermostat calls for heat, draft motor starts, flame ignites, blower starts and heats the house. After 5-10min, blower will stop but the draft inducer keeps running. After 2-3 min flame will reignite, blower will start and heat the house until the thermostat is satisfied. Could this be the limit switch or something else. The unit is about 10years old. Flame sensor was replaced last year, draft inducer was replaced about a month ago.