Triton Opal 2 Trips out RCD?

My Opal 2 shower trips the RCD in my consumer unit just as the heater element would start to heat the water, I have tested the elements in the can, there are two prongs joined together on one side and two sepearte on the other, one reads 12.5 ohms and the other is about 4M ohms, this also has a 0.5M ohm resistance to the ground connection. I think I need a new can (heater element) would this fault also damage the PCB or will I get away with just the element (Can)