annual maintenance contract for repairs and replacements to hot water generators of main boiler house skims soura , complete descaling of boilers including mountings , fittings , etc . with acid base descalant and neutralizing/rinsing of boilers . the job shall include replacement of man-hole and mud-hole gaskets and replacement of damaged packings , bush and balls of water level indicators , etc . , complete cleaning of fire tubes ( desooting and decarbonizing ) with steel brushes and rodding . the job shall include replacement of front and rear door gaskets and fire boxes gaskets , etc . , provided and replacement of castable refractory and brick work for the following if and when required:1 ) quaral . 2 ) rear door . 3 ) rear and front door fire boxes , etc . 4 ) front door . 5 ) rear door for dry back . , repaired cracks of end plate ( tube to tube ) ligment after v-grooving , grinding , welding and d . p . testing before final welding . , providing , fixed and replacement of seamless fire tubes ibr quality with material test certificate of following sizes after extracting the leaked tubes . the job shall include expanding of tube ends , welding , etc . , 2700x63 . 5x3 . 66mm , 3580x63 . 3x3 . 66mm , extraction of broken studs of front and rear doors , providing and fixing by welding of new studs of required size along with clamps .