D PREPARATIONS In order to assure an efficient inspection and/or revision, the following preparations are to be made: 1.Shut-down of the plant and cooling out of the heater to make entering for inspection possible. 2.Dismount burner with supply piping (fuel, electric connections, air connections etc.) as far as necessary. 3.Dismount burner supporting insert (4) Caution: for protection of refractory lining, place insert on wood. 4.Take off caps of cleaning nozzles (5) 5.Take off center insert (2) of the lower part. 6.Installation of a ladder to allow inspection of the whole interior of heater coil.