Storage Heater - charging rate

[NEC]

My one storage heater Dimplex is not getting hot as expected. Relatively new bought second hand. I am monitoring the charging rate and it seems to be spending more time off than on - is that right? I would have thought that it would be running a continuous charge till it was full and pretty much 'red hot'. any thoughts please? thanks.

[ericmark]

I used one to test iron laden concrete blocks with idea of using them to replace the clay ones used. The one I had would go on until the temperature set before starting to cycle off and on which would takes quite a few hours.

However it took quite a time for the heat to start coming out so how one would know when at the 900 odd degs C it reaches I don't know.

At 1/2 hour we had problems as water started to be expelled from the bricks so clearly at 1/2 less than 100 degs C. While I was working on project cure was not found seemed there was a chemical change and however long we left new bricks water came out. Once heated first time even if soaked again there was not a problem. But to heat to over 350 degs needed to ensure full chemical conversion would cost more money than saved using cement instead of clay so think idea was shelved.