Hello, I need to get clear on this sequence. Please tell me if I am accurate or not, and in great detail what the furnace is doing.
1.Thermostat calls for heat
2. Inducer fan comes on.
3. two seconds later you hear a faint click as the pressure switch closes
4. Inducer blower keeps running for 30 to 50 seconds, then the control board closes 2 relays, one for the igniter and one for the gas valve.
You can hear those two faint clicks.
5 Burners ignite.
6. about 30 seconds later the main blower (not the inducer fan which is already running) comes on.
7. The burners stay on until the house is warm...OR the burner goes off because the flame sensor is not sending the flames... that can happen anywhere between 4 to 10 seconds after the burner lights as a rule...
In that case, the furnace will try to fire 3 to 5 more times, same cycle... if all 5 times fail, then it will lock out the controls so that you must do a 'soft reset' by cycling the thermostat OFF then back ON.
Please comment in detail, we can go from there