Ace High Flow switch/Diverter valve?

Hi all,problem is mine is leaking from dhw plunger area,slide to hold micro switch box is rusty,little bit of water inside box,but most runs down heat exchanger.Will replacing diaphram on right side stop this,or is there a diaphram on left side were dhw plunger is.Cant see any access to plunger on left side.

Ross
November 2010