I have reset my Siemens RDJ 10RF and RCR 10/433 - Boiler still won't fire?

After the heating did not come on with my Baxi boiler, I checked the batteries on my Siemens RDJ10RF thermostat. I thought maybe the unit had lost connection with the receiver and reset them. I had the green light, but still no heating. Any movement on the dial of the thermostat was transmitted to the receiver, but still no heating. Hot water fine. Help?