If the oil pump pressure checks out good but the furnace won't light, what is a potential problem?

In situations where the oil pump pressure is good but the furnace fails to ignite, one potential issue is a plugged nozzle. The nozzle is a critical component in an oil burner system, as it atomizes the fuel oil into a fine mist for proper combustion. If the nozzle becomes clogged, either due to the buildup of contaminants or debris in the oil supply, it can prevent fuel from reaching the combustion chamber effectively. This results in a failure to ignite as the necessary fuel-air mixture cannot be achieved, despite the pump delivering adequate pressure.

Understanding the role of the nozzle helps in diagnosing ignition problems, as it directly impacts the efficiency of fuel delivery to the burner. It's essential to regularly inspect and clean or replace the nozzle during maintenance checks to ensure reliable operation of the furnace.