Sounds like Silvia has an auto-reset thermal safety breaker on the pump. I know of one USA reseller who sells a thermal fuse of that sort that can be installed on any vibratory pump. Sounds like it did its job. Did the thermal safety thermostat on the boiler trip? Thats a long time to run empty, but if the boiler safety didnt trip then you are probably OK.
This is a good lesson, and yet another reminder, that using a timer on a machine that does not have low water shut off nor auto-fill can be a costly undertaking if due care is not taken.