Do check it is not the circuit breaker in the main circuit board, the one outside the bathroom or the one in the water heater itself first. My MEX has a reset button on top of the boiler which tripped when a house lizard got inside and got fried. Engineer fixed that in 20 seconds. Now I know.
If you get a new one the same model it will fit directly onto the holes drilled for the old one and fitting is then dead easy. All water heaters might have the same hole pattern but not sure.
Anything codeine based I was told us illegal in Thailand for example co codamol. However, I have brought controlled drugs into Thailand and flown with some that are banned on aircraft. I declared them, showed the prescription and I was allowed to carry them.
Strangely enough my local immigration office will not providecaxresidenceccertificare for this purpose. I have to go to land transport and register and they get the certificate of residence I need. Takes about two weeks. Ask at you local landctransport ifficexas you will have to get the blue book in your name and possibly change the plates. In total, it took 7 weeks to get the blue book for my last car into my name and that was with the help of dealer who sold it to me.