Having climbed into the firebox the inspector taps every stay with a hammer to hear if any have cracked. He looks in all the opened holes to check the general condition of stays, fire tubes and other structural components. After a quick cup of tea he gives it the all clear with only a couple of minor items to sort before the next test. Now that's done everything has to be put back together with new seals and tested for leaks. It will then be fired up for a steam test where the safety valves will be checked to ensure they blow off at the required pressure (50psi) and that the gauge is reading correctly, water sight gauges work etc.