Nanni V6.270 Instruction Manual

Nanni V6.270 Instruction Manual Manual pdf 26 page image

Maintenance28Protection against corrosion - Zinc anodeWhen at least two different kinds of metal are immersedin seawater, polluted water or water with a high mineralcontent, a chemical reaction occurs and an electrical currentis established between the metals.This electrical current leads to the metal that is more activefrom a chemical point of view, or more anodic metal beingeroded. If this is not controlled, this galvanic erosion canseriously damage the parts and propulsion system that areexposed to water.In order to protect the engine and the seawater coolingsystem from corrosion, the engine is fitted with two sacrificialanodes located on the end cover of the exchanger.To remove the anodes• Let the engine cool down• Close the seawater intake valve• Drain the seawater system• Remove the set formed by a cap, a seam and the anode.Remark: Remove the deposits from the surface of the anodeusing glass paper before determining the level of erosion. Donot use a soft steel brush as this could leave deposits thatare likely to speed up corrosion.If more than 50% of the anode has been used up, replaceboth it and the seal.I Attention! : Screw the anode cap back on tightly and donot forget to re-open the seawater intake valve.