The hydraulic test checks the structure of the boiler. The steam test also checks the accessories attached to the boiler. Particlularly the saftey valve/s. Not only must it (they) operate at the correct pressure, but with the blower full on and the maximum rate of steam generation, they must be able to ensure that the pressure doesnt rise above the stated pressure. Alan --- Charles & Dorothy Brumbelow <cbrumbelow@xxxxxxxxxxx> wrote: > Please explain for this Yank what a steam test is, > Alan. Thanks, Charles > > ___________________________________________________________ Win a BlackBerry device from O2 with Yahoo!. Enter now. http://www.yahoo.co.uk/blackberry MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.