Halstead Ace High no DHW

[sadie100]

hi there i have no DHW but do have CH.I have followed the diagnosis for fault finding i do have 5dcv across the DHW thermostar and have changed DHW flow switch but have noticed when demand for hot water the pin on the group set does not extend to engage the flow switch.
Any help would be appreciated.
Tim

 

[kevplumb]

change the diaphram

 

[sadie100]

thanks Kev is the diaphram inside the group set
tim

 

[kevplumb]

View media item 15540
round disk near the prv on the right

View media item 16661
oddly labeled flow switch

 

[sadie100]

thanks kev
bit tight changing the diaphram but worked fine on completion thanks for your help.
tim