Hot water from tank how does it work as i'm wanting to add solar and iboost

[Tally101]

Hi All
I have a hot water tank thats connected to Vaillant boiler that heats up at the times programmed. I have never thought about how it works but now im thinking of solar panels, battery and the iboost. Before I fit these I need to know how the hot water works and then how it will work with the iboost.
ie does my tank heat up to the temp when it hits the timing to start up " say if it programmed for water for 2 hours does it just top up the water if its used and heats it up again" and how would the iboost work if its up to temp will it still send power to the immersion heater or export it ?
thanks all

 

[stem]

The Solar iboost monitors the amount of electricity being exported to the Network and diverts it to an immersion heater when it is generating sufficient power to do so, and you aren't using it up elsewhere in the property.

The boiler is a completely separate heating system and not connected to the solar so will work completely separately. Think of it as having an open fire and an electric convector in your lounge. Both will heat the same room but work completely independently. Its the same with the hot water. The boiler and the immersion will both heat the same hot water cylinder but work independently of each other.

 

[Madrab]

The cylinder has temp controls, one to talk to the boiler so when the system (programmer) says, heat up the hot water the boiler says 'cylinder are you hot enough?', the stat on the cylinder says either yes or no. So the hot water is controlled by the programmer via the thermostat as to when the boiler heats the hot water cylinder - so that can be programmed separately.

The immersion heater (IH) (electric) is usually turned off when a HW cylinder is heated through central heating and only used as a back up. In the case of using electricity from the PV panels then the IH would be connected to the PV system and not the mains and always on. The immersion element has a settable stat that says, am I hot enough, no ... power the element till I am then turn the element off.

Once the IH is turned off the electricity from the PV should then be exported

 

[SpecialK]

You need a dumb immersion - one thats just a thermostat and overtemp. Ideally wire it to the bottom immersion. You will need to run a wire from the immersion to the iboost which will be located near your electric incoming unless you get the remote CT clamp.

Keep in mind its possible to get 15p/kWh solar export rate from octopus. Gas is about 11p/kWh (not 100% efficient). An iboost is £350 or something so payback could be a long time. Nothing beats making your own hot water though!