i have a WR1 british gas wireless system red and green light r on but no he?

please can somebody help my greenstar 28i junior combi mk111 is working and giving me hot water on demand in the kitchen..
then on my WRI british gas system has the red and green light on but wont give me any heating. ive changed the battery in the hall and that is displayin 21c but wont let me turn it up!!
ive bled all the radiators which had no air in, but still no heating!!
PLEASE PLEASE CAN SUMBODY HELP AS IM FED UP OF BEIN COLD.. Plus i have very limited funds..