Question about immersion heater

Quite a simple one but can't seem to find the answer anywhere.  If I switch on the optional immersion heater on my boilermate iii is is controlled by the PCB, i.e. will the boilermate switch it off when a certain temperature is reached ? or will it just continue to heat eventually boiling the water even in the FE tank ?

I think the system uses a typical immersion heater which has its own thermostat inside it, you can check by isolating the unit and carefully removing the cover on the immersion you will probably see a thermostat with a small dial on top to select the temperature.  If this is the case then the unit will reach the preset temperature set  on the dial and then cycle on and off to try to maintain the temperature assuming the thermostat is working as intended of course

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Regards Murray