Hello Liz
The Right hand dial is the input power, this sets how much heat is stored overnight, Try about 4 to start with. make it higher in cold weather and lower when hot outside.
Remember that any new setting of the input will only take affect over night when the electricty is on and heating it up.
The left hand dial controls when a boost of heat comes out. I think of the numbers representing time in the afternoon. A lower number sets a flap to open earlier to let the stored heat out, a higher number keeps the boost flap closed until later in the day. Set too early could let it out too early so you have insufficeient heat later in the evening. The dial alters when you need that boost.
Try 5 to start with.
Andrew Holley
September 2008