This paper reports the results of specifying and verifying the steam boiler problem with Promela/SPIN. Several models of the system have been produced with different degrees of completeness. Each model represents an abstract level for capturing the original problem requirements. The last model is very detailed and gives a first solution to the steam boiler problem. The model is able to drive the system and takes device failures (pumps, pump controllers, steam and water) into account. Liveness and safety properties have been successfully checked on the models to insure that the system behaviour is correct. An implementation of the system has been made using Synchronous C++, a concurrent extension of C++, and linked with the TCL/TK simulation. A presentation of future evolutions of the system is also described. This application shows that SPIN is quite appropriate for developing control process problems from specifications