Geyser troubles - in hot water after 27 years!

On a Sunday morning about 27 years ago we had a geyser burst. I called on Jan Nel, our home teacher at the time, to come and assist with cleaning up and assess things and then the following day I called on Robert Bothwell to replace the geyser.

Robert replaced it the following day with a copper lined Kwikot 200 litre 200 kPa geyser. This has a 4000 Watts heating element and served our family of 7 and occasional visitors very well for more than 27 years. It is worth spending more for a copper lining and larger geyser.

I set the thermostat on about 47°C with the idea that, 

1. if a child (or adult) put his or her hand into only hot water they would be uncomfortable, but not injured, and 
2. thinking of my training in physics, this is maintaining a shallower temperature gradient and so should not cost anywhere as much as maintaining water at a higher temperature. 

I do not recall ever running out of hot water, even when the home was fully occupied and all were showering in the morning, and washing dishes, and all.

But all things do age and become less effective.

I had investigated and tried replacing the thermostat with one that Robert Bothwell had in stock, but that blew immediately and so I called on Peter Lloyd, a plumber who works on our Cape Town area chapels, to come and replace the heating element and thermostat. We had replaced this geyser in about 1993 (according to the date shown on the old element, a copper-lined geyser. It was quite clear when the old element was removed as to why the thermostat blew. The copper coating of the heating element was completely disintegrated in a lot of places and so electricity would have been going through the water to short-circuit the element!

It took about four days from the problem starting before I called on Peter, and I was impressed at how effectively the water remained hot in the geyser for many days without being heated. The thermal insulation is highly effective!

I could hear the water sizzling or hissing inside if I turned on the power to the geyser. Then the wiring blew and the need for replacement became more obvious.

All is now well with the new heating element - thank you Peter Lloyd, the plumber.

Below are pictures showing how seriously the element had deteriorated. The conducting element can be seen in places within the white insulating layer inside the copper coating. The thermostat looked fine although it was broken.