Procedures followed during the maintenance of water tube boilers :
Remove the air register (s), clean thoroughly and check for proper operation.
Diffusers and burner tubes which are prone to get dirty/clogged are cleaned.
Register-flaps if worn due to their oscillating movements are repaired/renewed.
Superheater tube compartment is to be thoroughly cleaned of dirt and the tubes must be properly inspected.
Stiffeners/ supports may be checked and renewed as necessary.
Water-washing may be carried out provided the refractory is not affected.
Soot and deposits are cleaned out from the furnace and tube-walls.
The main tube-bank and fire-row tubes should be examined for damage and cleanliness.
Sliding feet for the boiler frame is to be checked and greased.
During commissioning back, the boiler should be checked for steam and gas leakage.
Following are the additional procedures carried out for major overhauls:
Header tubes and water tubes as accessible through the hand holes should be inspected by an introscope and internal of the steam drum should also be checked.
Improper boiler fittings should be dismantled, checked, grounded/polished and repacked.
Soot-blowers are overhauled and refractory damage must be repaired.
Chemical cleaning may be required in consultation with a specialist if deposits are found in the boiler tubes in spite of water treatment.
The chemicals in use are usually sodium carbonate (added with sodium phosphate if required and in a proper solution) and anhydrous trisodium phosphate.
While water-washing, drain connections are to be provided / kept open in the boiler floor.
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