How to Derate a marine boiler

1.Reduce max working pressure of boiler
2.Change the safety valve to larger size diameter
If you change the safety valve then need to increase corresponding waste pipe dia and also safety valve cut chest cut size need to be increased

Option 2 is bit complicated so we go for option 3.

3.Reduce the firing rate by following

Change the nozzle
Dp transmitter need to be recalliberated
Steam cut in/ cut off will as per new max working pressure
Set the safety valve for new max working pressure
Accumulation pressure test to be done in presence of surveyor

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MEOclassIIexamnotes

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