OICEW Task 4.3.L

Bottom blow boiler

MMA Method

In order to satisfy NVIC 17-14 Task 4.3.L , MMA students must:

NVIC Method

See NVIC method.

STCW Competence Knowledge, Understanding, and Proficiency

Operate main and auxiliary machinery and associated control systems

OICEW-A4.3 Preparation, operation, fault detection and necessary measures to prevent damage for the following machinery items and control systems

Steam boiler and associated auxiliaries and steam systems
Condition Behavior Standard

On a vessel of at least 1,000 HP, on a simulator, or in a laboratory, under the supervision of the Chief Engineer, and when directed,

the candidate performs a bottom blow of a boiler.


Note 1 A candidate who does not perform this task will receive an endorsement that is not valid for steam vessels.

The candidate:

  1. Performs bottom blow when directed, slowing main engine to prevent carry-over or other adverse affects on steaming boiler;

  2. Secures fires in boiler and opens superheater vent to boiler;

  3. Secures main-steam stops to boiler to be given bottom blow;

  4. Using auxiliary feed stop-check, raises level of water in steam drum of boiler to 1 inch from the top of gauge glass;

  5. Opens bottom blow overboard skin valve;

  6. Opens water wall bottom blow valve;

  7. Observes drop in water level, securing bottom blow valve when level is no less than 1 inch from bottom of gauge glass;

  8. Repeats steps 4 and 5;

  9. Opens mud drum bottom blow valve and secures when gauge glass water level drops to no less than 1 inch from the bottom;

  10. Prepares to re-light boiler;

  11. Starts boiler forced draft fan and pre-purges furnace for 5 minutes;

  12. Raises water level to 2 inches below normal level;

  13. Re-lights burner and adjusts combustion air as necessary;

  14. Opens main steam stops to “float” boiler back on line, cracks open superheater and main steam line drains;

  15. Begins to return main engine to sea speed when boiler pressures are observed to be equal and slight drop in burner manifold fuel oil pressure is noted;

  16. Closes off superheater and main steam drains, and superheater vent;

  17. Continues to slowly re-establish engine speed; and

  18. Conducts round of engine room to verify that all steam systems and equipment are operating at normal levels.