its the one that faces you not the one that faces up.
to replace diaphragm:
isolate from power.
isolate cold water valve under boiler
open hot tap
remove microswitch screw
loosen impulse tube nut from diaphragm housing
(should allow air in to get extra water out tap)
proceed to unsrew the screws around the housing
keep pressure on brass housing as you undo screws as contains spring.
when all screws removed gently pull housing away.
replace parts as fitted. Replace diaphragm and the nut with packing gland on the front where the pin exits.
refit
take it you bought a service kit with the nut and gland in, because they all leak at some point so def change
iain, May 2008
