Glow-worm Energy System fault codes

19 codes from the Glow-worm manual for the Energy System gas boiler. Pick one for what it means, the likely causes and where to start.

Code	What it means
D.14	Operating mode of the modulating pump
F.00	Flow temperature sensor fault
F.01	Return temperature sensor fault
F.10	Short circuit: flow temperature sensor
F.11	Short circuit: return temperature sensor
F.22	Safety shutdown: water deficiency in the boiler
F.23	Safety shutdown: temperature spread too great (NTC1/NTC2)
F.24	Safety shutdown: temperature rise too fast
F.25	Safety shutdown: flue gas temperature too high
F.49	EBUS fault: voltage too low
F.61	Fault: gas valve assembly control
F.62	Fault: gas valve switch-off control
F.70	Invalid product code (DSN)
F.77	Fault: condensate or smoke
F.88	Fault: gas valve assembly
F.89	Fault: pump
S.42	Flue non-return flap closed
S.53	Product in waiting period / operating block function due to water deficiency...
S.54	Waiting period: water deficiency in the circuit (flow/return spread too large)