I quite fancy this myself, I would probably only go to Canada if I was gona do it though. I'm afraid I can't help with your question but if you find work overseas stick a wee update on this thread if you could, I'd be really interested to see how you get on. It'll maybe give me a better idea of how to go about it. I fit&repair domestic heating myself, I think they call boilers, 'furnaces' in north America for talking sake which could put u off track if looking for boiler repair work on the net. I think termonolgy is key when searching dependant on your chosen country.
Best of luck to you mate