Performance of 170 litre tank

Hi,
Given that the amount of water in the thermal store is 170 litres, how many litres of hot water is that likely to provide first thing in the morning after running overnight on off peak electricity?
If only some of the hot water is used in the morning, is it normal for the water to then be cold in the evening ? or should the remaining heat in the thermal store work fine later on in the day?
Any help very much appreciated !

Is yours 170 litres?
Depends on the temperature of the cold water entering the dwelling. Colder now so would mean a bit less.
I would say approx 100 litres plus.
Should tell you in the book.
All ref to water tamp as above
And if the store temp is correct.
If it has been ok.
Then check the water level in the top tank.
Rod stat needs check and bottom heater.
Could try swopping top and bottom stats over.
Also do a flow test.
5 litre bucket, run the shower etc. Time it. 30 seconds would mean 10 litres a minute.
You are using more than that.
May be 15 litres.
So 10 minutes would be 150 litres.
Mike

Thanks Mike, I'll run a few tests!

Just got around to doing flow tests using bath tab I filled a 10 litre bucket in 30seconds then timed 7 minutes worth of hot water making 140 litres from a 170litre thermal store - is there anything I can do to get more hot water out from one off peak / nighttime heating session? Thanks in advance.

Well you are using 20 litres in a minute. Just over 4 gallons!
You could check the temperature of the store in the morning before using any.
The rod stats could be out a bit, but are preset and sealed normally.
The heaters could be getting old and thus not so efficient.
Another could be the heater/s are scaled up with lime scale.
I do not think you have any plate heat exchanger problems as the flow rate is good and you have not complained of DHW temperature.
Check the DHW temperature as the DHW sensor could be giving you to hot water. Thus using the store.
But I do really think that to receive 140 litres of DHW heated via the 170 litres with in the store is quite good.
Perhaps try to get E 10 instead of E7.
Mike