The green light shows that the boiler should be on. But if it isn't going on/off, there is something not right with the thermostat / receiver. However, in this state I would expect the boiler to be continually on when the green light was showing.
First of all try turning the power off to the receiver so that all lights are extinguished. Wait a few minutes and restore power. The older versions of the RT500RF had a switch on the front, but if yours doesn't have a switch it will probably mean turning off the power at the boilers fused spur.
After that, if nothing has changed and the boiler still doesn't work you can still do the test as I described and if the boiler comes on then you know the boiler is OK.
First of all try turning the power off to the receiver so that all lights are extinguished. Wait a few minutes and restore power. The older versions of the RT500RF had a switch on the front, but if yours doesn't have a switch it will probably mean turning off the power at the boilers fused spur.
After that, if nothing has changed and the boiler still doesn't work you can still do the test as I described and if the boiler comes on then you know the boiler is OK.