Sabe HE boiler,green light flashing but no hot water?

I was away for a few days and the unit was not used for over a 24 hour period. I filled the pressure to 1.5 and let the hot water run for nearly 10 min and no hot water. I shut the unit to off for a few seconds and turned it back on but still no hot water. I can hear the pump go on and it sounds like all is working as usual however still no hot water.