I have same type of water heater in my house.

Storage water heater. So, the tap has mixer to mix hot and cold water to your preference. Mine is mounted on the ceiling. Nothing to maintain though. Yes, got pressure relief valve.

However, in this case the guy said the heater is switched off. Maybe he thought so but actually was still on. If not, no reason to explode.

I'm resting in peace when I get home from office

The heater was broken and I got it replace about 2 years ago. Costed me about RM100

The valve has lever that can function as bleeder to empty the tank if you need to change heater element. I have to insist the installer last time to connect small pipe to channel water down into bathroom because he said it is not necessary. He think that the heater can last forever or what

Once water reaches certain temperature the power will cut off. It is not boiling temperature though. Maybe the sensor was also faulty

I cannot imagine using solar type in Malaysia. During hot sunny day, you don't need hot water. During rainy day, the water is not hot

The central storage also electrically assisted when needed?

No lah. The concept is old because this was develop first before instant water heated. However, it is still in use and popular. You can use one tank to supply hot water to 3 bathroom for example, instead of installing water heater in each bathroom

http://www.joven-electric.com/product_main...g?category_id=1