After the bottom flue sheet on the boiler is drilled and tapped for the piping associated with the boiler blow-downs, the top flue sheet must be prepared.  Around the top circumference of the boiler are three 1/8” steam connections that supply steam to the water automatic and low water cut-off; the steam siphon and burner vaporizer enema; and to supply steam to the water indicator, stack blower, steam pressure automatic, and the dash steam pressure gauge.  A 3/8” connection is required for the safety (pop) valve, boiler water supply inlet, and at the center of the boiler a 3/8“ connection for the steam supply line to the throttle and engine is installed.  Once the boiler’s piping connections have been drilled and tapped, the boiler’s interior is blown clean of any metal chips and filings from the drilling and tapping operations.  The boiler is now ready for the flues to be installed.