We've got a Buderus G115 that was installed shortly before we moved in a few months ago. My wife noticed this evening that we lost hot water and when I checked the boiler, the display showed 'burner error' and the [incorrect] time was flashing. As per the manual, I pressed the reset button, but that did nothing. I put in a call to the tech that has serviced this house in the past and he suggested that I shut it off for 5 minutes and then try again, and told me to call him back then. I left him voice mail, but I'm wondering if there is anything I can do to manually run hot water in the meantime (it's Sunday evening and I'm not expecting a call back at this point). The owner's manual seems to be pretty vague about these error codes. I also switched it to manual mode, as per the manual, but I'm not sure what that does.
Anything I should check for?

Thanks