No heat. Cycled system. Pre purge would cycle, but would not engage igniter. Checked filter. It was dirty, but not too restrictive. Found code of 23, witch is a pressure switch failure. Found obstruction in drain lines. Cleared and system would still not fire. Checked pressure switches and found them both full of water. This was causing them not to operate properly. Cleared as much water as I could out and cycled several times. System fired and is operating normal at this time. Recommend full clean and tune to check for any additional issues with this system. Job complete.