I have a carrier furnace it starts up fine the little fan starts up the piot comes on then it goes click click and theburners ignite then the problem starts OK after the burners are lit they stay lits for 30 seconds or so and go right back out leaving the pilot lit then click click and it will light for just a min and go back off doing this a number of times so then if I take the cover off the box where the burners and piot is it lights when it clicks one time and the burners stay lit and run fime as long as the box is off . We tried taking the vent that goes to the top of it and it wouldn't stay lit then either so as long as the front to the box is off we have heat
Please someone help me I have a two year old and not much money please help

I have seen that somtime their is a screen inside of burner compartment in the fresh air inlet on the furnace or on the underside of the top of burner compartment

i have seen that somtime thier is a screen inside of burner compartment in the fresh air inlet on the furnace or on the underside of the top of burner compartment
There is a screen there but it is not clogged or anything therer