how can i repaire triton t100xr?

triton t100xr is not producing a hot water, it has 2 boards primary board and countrol board, on the countrol board i have changed three gate ic's and on the primary board i have changed 2 realays which i had to change because of it's condation i'am still on the same boat,some one out there with the salution. Sorry had to put electric toothbrush instead of electric shower it seams its not in the catergory