How to replace a Diaphragm on an Alpha 240p?

Hi,

I have a very very small leak from the DHW Flow Valve on my Alpha 240p.

There is a very small leak from the front bolt on the DHW Flow Valve where the pin is pushed out of to activate the DHW flow microswitch. The water is leaking from the hole the pin is pushed out of.

Would this problem be solved by replacing the Diaphragm? If so, how do I replace it? I can get to the Diaphragm but unsure how to take it off.