i am a g s r p went to look as this boiler for a friend on sat the pin from the diaphragm moves up and down (it has a small plastic top hat on it) this pushes up to make the switch on the solenoid but still have a poor flow rate when the tap is off and the pin is down i put my screw driver through the hole in the solenoid turn tap on pin rises pushes against screw driver and have a good flow but no hot water could this be just the diaphragm or something else c/h works fine any any ideas 
