Gulfstream 2000 Thermal store thermostat?

I assume there is a thermostat controlling the temperature of the store. I assume it can be replaced if faulty but I can't find reference to it. I think it is faulty because the hot water temperature is far too high, and always has been and the entire unit gives too much heat despite it being insulated.
Can anyone enlighten me

Have you the book on your unit?
If not down load one for FREE at Gledhill's website.
All will be revealed.
Mike
MGC/H2O
Norfolk

Mike I have indeed and i don't find it revealing enough, hence my question :-)

Well according to the book / manual.
There is a sensor called the store sensor. That is the unit temperature.

Then there is a DHW sensor for the hot water.

So if your DHW is to hot that could be the trouble.

Being a gas thermal store.
When it is serviced every year, then that would / could check that the unit was safe, operating correctly and perhaps even an explanation of how it all works.
There are many reasons / factors why things go wrong / don't work.
Mike
MGC/H2O
Norfolk

Mike
I had a fault with the DHW sensor before and the symptom was lack of temperature control on exit. The problem now is too high a temperature in the thermal store. I know that they name a thermal store sensor but I don't know physically where it is, that is my main problem. The MIs don't show it.
Rob

3 sensors
DHW sensor you know that one!
PHE sensor is on the pipe behind the DHW sensor.
Store sensor listed in the parts section in the book.
It is wired from the main board to the store.
It is located at the front of the unit perhaps a quarter to a third from the bottom.
It is a dry sensor.
The book may not be to clear, but that info is there and can be worked out.
Mike
MGC/H2O
Norfolk

I will look again and presume that this not the same as the store overheat sensor.

Well the boiler side of your unit will have other things.
But to give you a start
Look at the wiring diagram and those 3 sensors I mentioned.
I would not sent you into the boiler side of things.
As I would think you are not gas safe?
And also if you were, well you would not be asking these questions.
There are other sensors etc on the gas side.
But the store sensor tell the boiler I want heat or hey I'm happy switch off.
Perhaps a good service and thorough check could be the order of the day.
Mike
MGC/H2O
Norfolk.

Correct Mike I m not a gas safe fitter. And i don't think the fault is anything to do with gas or calling for heat at the wrong time. I think the range of the sensor is too high which means to me it is either faulty or not in contact with the store very well.

Right so forget about the other sensors.
You have 3 to look for.
DHW you know
PHE is very near that
Leaves one to find, it just pushes into a pocket.
Any fault codes?
That would / should/ can tell you if any of those are faulty?
When the unit heats up, how long?
Tried test the unit temperature with a temperature probe?
The unit should be hot when fully heated 70 to 76c.
So is it hotter than that?

I really think you should get some one out.
As there could be other issues going on.
Your description of what is happening / not happening is a bit confusing.
From a safety point of view a check would be best.
Have you had it serviced?

No fault codes but the overheat sensor trips out and that is at about 82C. The amount of heat exuded by the unit suggests either insufficient insulation or excessive heat.

Well fault codes do not always work.
Change the sensors first.
Where are you taking the reading from?
Ref the 82 c

No, it's probably internally consistent.
Measurement is by finger! (for hot water temp). Heat dumped by unit would suggest either a poor design or too hot store.

Well you have the store temp which is the dirty water.
Then you have the DHW temp.
Both different.
You need to check with temp probe.
All thermal stores in cupboards are pretty hot.
Even a normal cylinder is ( airing cupboard)
Have you been living there long?

But the store overheat shouldn't trigger regularly. I will go round with a probe. But not now.