Worcester Bosch Greenstar Ri Boiler Error Codes Leave a Comment / Boiler Fault Codes, Worcester Bosch Boilers / By Emergency Plumbers / May 3, 2015 May 3, 2020 / Worcester Bosch Greenstar Ri Boiler Error Codes Worcester Bosch Greenstar Ri Boiler Error Codes Fault Description System Behaviour No light No power at control board Light on Appliance on but not operating during demand Slow flash ( mostly off flashes on) Ignition lockout Slow flash ( mostly on flashes off) Flue overheat or heat exchanger overheat Fast flash Volatile lockout sensor fan or code plug 2 pulses Check service mode switch is in minimum position 5 pulses Check service mode switch is in max position