I had normal pressure on my boiler and everything was fine until i woke up next morning and there was no pressure and central heating and hot water indicator lights were flashing. I pressed reset button and tried to fire up the boiler whiched worked for about 30 seconds but stopped again. Tried to re fill the system and get pressure back up but gauge just stayed at zero.
There may be a pressure valve that has automatically opened. Look for a pipe that discharges to the outside of the house. Try filling the system and get your loved one to stand outside watching for gushing water. The valve can be reset, but each boiler is different and I can't advise on how to do that - I've got exactly the same problem!
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.