I don't know if this right catergory but been having cold showers forever.First I think because water from town weak but now I don't know.Some times I get hot water for a few a minutes and then it shuts off.The heater over 5 years old and by Thai standards it's out lived it's service by about 4 and as half years.So how would I check if it still works.Don't have any experience with these things.