Cylinders don't go faulty like that, the insulation is a permanent feature which doesn't change, the thermostat maybe on all the time in which case you would see water coming out of the overflow pipe and running into the gutters onto your roof.
The old cylinders are better than the new ones it's not true that the insulation on the old cylinders is that much worse, these days they are built very poorly.
I have been into the factory where they make the cylinders from scratch here in CHCH and the standards are very low.
If your water is very much hotter than usual then it may be that the thermostat is reaching the end of it's life and has altered calibration, 1965 is quite old. The earthquakes here destroyed many a hot water cylinder, big leaks, including my new one and adding chlorine to the water to stop contaminated water (mud from broken pipes) caused pinhole faults in the copper linings, had to replace the cylinders again, good business for the plumbers here.
The old cylinders are better than the new ones it's not true that the insulation on the old cylinders is that much worse, these days they are built very poorly.
I have been into the factory where they make the cylinders from scratch here in CHCH and the standards are very low.
If your water is very much hotter than usual then it may be that the thermostat is reaching the end of it's life and has altered calibration, 1965 is quite old. The earthquakes here destroyed many a hot water cylinder, big leaks, including my new one and adding chlorine to the water to stop contaminated water (mud from broken pipes) caused pinhole faults in the copper linings, had to replace the cylinders again, good business for the plumbers here.
It's not the least charm of a theory that it is refutable. The hundred-times-refuted theory of "free will" owes its persistence to this charm alone; some one is always appearing who feels himself strong enough to refute it - Friedrich Nietzsche