Wow, you are game, there is absolutely no way I would leave a grow set up running in my house for 2-3 unattended. The risk is low for a fire, but not zero. I would be more worried about the lights catching fire, but I suppose you could just go to the shops and have something go wrong, but that would be a much better scenario than being 1600 km/1000 miles away at the time. I would suggest that next time you went away for any amount of time, that as Frigault said, at least have a trusted friend with access to your place to be able to step in, in case something like the fan issue were to happen again. Personally I would rather lose a plant or three, rather than my house. And unless you are in a legal "home grow state", you may find that your insurance will not cover any claims, should they arise from illegal activity. As a former fire fighter, I see leaving your house unoccupied for three weeks with a grow room in operation as a recipe for disaster. The amount of fires I attended with people saying "I thought it would be all right" or "I was only away for a couple day" and had fires due to electrical faults in their grow set ups, is frightening. I would suggest in future that if you need to go away again,, either have some one house sit for you or unplug your growing system. While the chance of fire is low, it still is ever present and to potentially lose your house and all your possessions just for the sake of a couple of plants, is bordering on extreme gambling. I do hope everything will be ok for you, but would suggest never doing it again, ever!