Found after giving the furnace a call for heat the furnace ignited and the blower came on. After running for about 10 minutes the furnace shut off and you could hear water gurgling inside the furnace. Found condensation drain is clogged inside the furnace. Blew out the drain with nitrogen and cycled back on furnace. Furnace is now draining fine. Found broken and rigged inline drain assembly on furnace. Also found when furnace lights up it was lighting pretty hard due to burners that are rusted and corroded. Customer would like an estimate on adding an intake pipe to the furnace. Furnace is a 2003 and should really be replaced. Performed a combustion test on the furnace and took photos of findings.