Please help

[Kirstyguy]

Hi, my husband has replaced the diaphragm on our glowworm 100e combi boiler. However when he turns it back on the pressure is going through the roof. He thinks it might be the way the diaphragm has gone back together. Is this right? If so, what can we do as we currently don't have any heating.
He has replaced it before a few years back. Just wondering if there is something he has forgotten to do?
Thanks

 

[PrenticeBoyofDerry]

has the vessel been recharged?

 

[ianmcd]

he cant have done anything with the diaphragm that will cause the pressure to rise, does it rise all the time even with the heating switched off ? if so the filling loop has been left open. if it only starts to rise when the heating is switched on then as already suggested the expansion vessel needs recharging, my guess is the filling loop is open as he would have to isolate the cold water supply to change the diaphragm and if the pressure is rising when he turns the water back on that it is the filling loop left switched on