Pulsacoil 2000 timing advice needed

I recently moved into a flat with a Pulsacoil 2000 water heater, but without Economy Seven electricity. I discovered this only when my first electricity bill came - it was enormous. After some discussion with the electricity company and some calculations I suspected that as a single self-employed person often working at home (therefore sometimes needing heating, which is all electric, during the day), Economy 7 does not necessarily make sense. I have had my electrician replace the inflexible Economy 7 timer with one which allows me complete flexibility on the Pulsacoil timing. For one shower or bath a day, plus the usual washing, washing up etc, how long should I need to heat the Pulsacoil for ? Would an hour before I get up and again in the evening be enough, or should I schedule it for more ? Certainly seven hours a night on a standard tariff was costing a huge amount and providing more than enough scaldingly hot water. Of course I can work this out by trial and error, but any advice or indication you can give would be very helpful ! Many thanks in advance.

Thermal store means what it says.
If on for 7 hours it will not heat up for all those hours.
As once heated to the designed temperature it will be satisfied and switch off.
If the unit is hot then you will get the hot water.
If you cut back on the time then it will have to heat up more.
The water temp at the taps will be 50 to 55c.
So if the store gets to low.....
Mike
MGCH2O
Norfolk

Thank you - so it will be a question of trial and error and looking carefully to see if it makes a difference when the next bill comes in. So far just one hour last night provided more than enough very hot water for my morning needs without the Pulsacoil blasting out the degree of heat that I am aware of usually even with the cupboard door closed.....

Perhaps you should get the stats checked.
Just in case they are faulty.
Should be 72c.
If possible take a temp reading from the big pipe on the top of the unit.
Mike
MGCH2O
Norfolk