red flashing button siemens RCRIO/433?

red button keeps going from green to red on RCRIO/433 Receiver, the boilers temperature often goes a degree above setting the boiler is still cutting in and out as normal but the receiver does not seem to stay green tried all the resets several times all prgrammes and times set correctly,changed batterys three times in RDJ1ORF thermostat,but the receiver comes on green for a short while then goes to red but the boiler still cuts in when called for, also came on at the wrong time during the night and i had to reset the clock.help please

cliff
November 2016