Dear Mr.Medina,

I presume that the viscosity of the diesel fuel entering the boiler may be 4 cSt. What you have to do is to heat the 230 cSt bunker fuel to a temperature so that the viscosity is around 4 to 6 cSt. This may be around 140 to 150 degC. The modifications you need will be the heaters and viscosity controllers. Because the heavy fuel density is higher, the spray pattern inside the boiler furnace may be altered. You have to check and adjust this. Other than this, I do not see a problem. This is my opinion based on common sense. Maybe you should get a second opinion from the boiler manufacturer.