I was in this field around 25years.I have assembled and re tubed,vertical,horizondal and U bundles many times.I have re tubed boilers,up to 2 iñch daimeter, tubes using all modern equipments,like elctronic tube expanders,hydrolic tube pullers,cutters etc...I have expanded tubes upto 2 inch daimeter, having tube sheet thickness upto 4 inch.
They forgot the New gasket. The bundle isn't level, going to hard to put the channel head and piping back on when the baffle plate is out 20 degrees 1:29