my furnace is a Goodman gmp100-3 rev b. When my blower comes on it fills my house with cold air for about a minute, then i hear the burner kick on. It takes it even longer to heat my house since all the cold air was pushed in for a minute. I've made sure the thermostat is configured for gas furnace properly. I was hoping to get some help with this and will appreciate any tips and troubleshooting given. Thank you very much.