This article discusses innovative solutions that solved vexing instrumentation problems and enabled commissioning an ammonia urea and complex fertiliser units on schedule.

Hopefully the readers would see from this article that thorough knowledge on the working principles of instruments is essential to troubleshoot and solve instrument problems. However, often the instruments themselves would be OK and the problems originate from overlooking some intricate vessel construction detail, and or processes details, which prevent correct process pressures reaching the instruments’ ports. Identifying such problems require instrumentation engineers going beyond instrumentation and gaining knowledge on the process and engineering details of process vessels. The case studies of this article illustrate these points.