you'd need to tell us what stat your using.
youve set it to request heat until 23 deg and the display is showing you what temp the room is at present. Most will show a flame alongside if the stat is requesting heat from the boiler.
we'd need to know what stat youre using before anyone may be able to help, as depends on make etc and whether its a wireless stat and reciever or hard wired stat??.
iain
December 2008