Qatar Fertilizer Company S.A.Q, Qafco operates four ammonia-urea fertilizer trains. The earliest since 1972, the latest since 2004. The last three urea plants are Stamicarbon design. Until recently Qafco only had experience with leaking high pressure equipment in Urea plant number 2, where the root cause was clear from the beginning. In the older plants, there is a higher chance for condensate contamination than in the newer design plants. Using an improved design, Qafco 3 (1997) and 4 (2004) run the condensate, boiler feed water and steam system on a zero-solid principle, avoiding any contaminants in their systems. As such, it came as a surprise that the high pressure carbamate condenser in Urea 3 (1997) developed a leak just within an hour, caused the plant to stop. Plugging of the leaking and surrounding tubes proved not to be sufficient. A new leak was suspected, and a second shutdown of longer duration followed. The enclosed paper will discuss the events, repairs and improvements that Qafco implemented to be even better in control in the future.