A plate heat exchanger assembly is provided having an anodic protection system comprising a plate heat exchanger frame, a plurality of heat exchanger plates mounted to the frame and means for selectively applying a voltage across the plates whereby during operation of the plate heat exchanger assembly biofouling and scaling is inhibited. The plurality of heat exchanger plates are mounted to the frame to define a plurality of heat exchange chambers for heat communication between a first and second process fluid being transmitted through the assembly. An insulating contact coating at points of electrically conductive contact between adjacent plates of the heat exchange chambers is provided such that the chambers comprise electrolytic chambers means are provided for selectively applying a voltage across said adjacent plates. A method of applying the insulating contact coating to a heat exchanger plate is also disclosed. The method comprises identifying points of electrically conductive contact between said adjacent heat exchanger plates and applying an insulating material to the points of contact.