Client stated no heating -Flame would ignite for a split second and then shut off when power from thermostat -Furnace cuts out on high limit after 10 minutes -Temp rise is good -Return intake is 16†but gets reduced down into a very small return grill (14x20) -There is not enough airflow being drawn from house to properly cool the heat exchanger -A new return needs to be cut in to increase intake cfms