Why is my Potterton Puma 100e hot water not very hot?

Hi, I have just replaced the Modulation Control Board on my boiler, which burnt out (the printed circuit on the back, not any of the components on the board).

The hot water now does not get very hot and have to run it very slowly to get any decent hot water to fill the sink, bath etc.

I have adjusted the hot water control to max on the front panel and this made no difference.

Any ideas would be greatly appreciated.

Thanks.