The bottom immersion comes on late at night to heat the whole cylinder.
The top immersion is there for you to turn on and heat the top section of your cylinder. You could change the switch for a timer type which would come on when you wanted to.
The idea is you heat the whole tank up on economy 7 during the night
and this provides the hot water for the next day. You can use
the top immersion heating just to heat the top part of the tank if you run out
of hot water but this is at peak rate electric.
Probably best to have the bottom immersion set to a high temperature
so you heat a lot of what to a high temperature and the top immersion heater
to a low temperate say 40-45.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local