Greeted John and proceeded to perform a PTU on a Navien condensing boiler. I opened up the unit to check and inspect all wiring with electrical connections. I pulled out the igniter w/ flame sensor. It was full of corrosion and decay. I cleaned the off, inspected the heat exchanger and reinstalled the sensors. Next, I removed the boiler water trap, flushed and cleaned in the slop sink. I applied plumbers grease to the trap seal and reinstalled the unit. I removed the fresh air intake filter and found it full of debris with a bees nest growing. I cleaned it off and reinstalled. Finally, I removed the condensate pump tray and washed off the beads with a colander in the slop sink as well. I closed up the cabinet to the boil, restored power and fired up the boiler. I observed it run, cycle and reach temperature. All is good at this time.