Arrived onsite for no heat service call. Performed diagnostic. Customer showed me thermostat set to 60 degrees with room temperature at 72 degrees. Fan turned on. Turned thermostat up to 75 and set fan to auto. System fired up. I changed the filter 14x24x1 provide by the homeowner. Recommend changing to 14x25x1 as the filter was sucked in. Cleaned the flame sensor. Ran the system.. received error code for high limit. Ran system again and system did not have ant errors. Home heated to set temperature. System running as it should.