Have a Burnham V15 oil-fired boiler for baseboard hot water heating system. Several years ago, the service technician replaced the fuel nozzle on the gun with a smaller version claiming that the system would be more efficient. Haven't noticed any increased efficiency - seems just the opposite. The furnace runs longer to heat the water albeit it probably uses less fuel for a given period of time. Besides obviously using more electricity to run longer, does the smaller nozzle really save on fuel over the larger factory installed nozzle?