Dimplex Creda TSR Automatic Storage Heater 79151C

This post is strictly to give Google something to index, for the benefit of North Americans who move to the UK and are baffled by heating
All that you need to know is the Rule of Twos.
Your storage heater is pretty primitive. It warms up big heavy blocks overnight when electricity is cheaper. For us, that's half-price between 12:30 am and 7:30 am. During the day, it releases the stored heat. What baffled us was: how does it know when the cheap periods are happening? Do we really need to come down at 12:30 am and turn up the Input knob?
The answer is NO.
Rule 1) The secret is this: your storage heater has two electrical connections. One for the expensive periods ("the day") and one for cheap periods ("overnight"). Between your smart meter and the heater, they manage this switchover on their own.
Rule 2) Set the Input and Output knobs to 2.
Rule 3) These are essentially primitive and slow devices, so after you do that, leave it untouched for at least two days. North American furnaces will heat up your house in minutes. These take a lot longer to settle into a new routine.
After two or three days you'll know how well things are going, and you can tweak either the Input or Output knob to get more or less heat at various times of the day. Then leave it again for a couple more days. This can't be rushed.
Honestly, these things are kind of brilliant, but understanding them can be tough.