Low
d.09 on Glow-worm Ultimate3 Combi

This code is simply a status message showing the temperature level your thermostat is requesting from the boiler, rather than an actual fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

TargetheatingflowtemperaturethatissettontheeBUSroomthermostat

From this model's manual
Verified against the Glow Worm/Glow Worm Ultimate3 Combi installation & service manual, page 41.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check your room thermostat screen to ensure it is set to your preferred temperatureObserve the boiler display to see if the status code changes once the target temperature is reachedNo action is required as this is normal system communication

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Related fault codes

d.00View →d.05View →

All 170 fault codes on the Ultimate3 Combi

Seeing a different code? Every code this model can display, in one place.

d.00d.01d.02d.04d.05d.06d.07d.08d.10d.11d.13d.14d.15d.16d.17d.18d.19d.20d.21d.22d.23d.24d.25d.27d.28d.31d.33d.34d.35d.36d.39d.40d.41d.43d.45d.47d.50d.51d.58d.60d.61d.62d.64d.65d.66d.67d.68d.69d.70d.71d.73d.75d.77d.80d.81d.82d.83d.84d.85d.88d.90d.91d.93d.94d.95d.96F.00F.01F.10F.11F.13F.20F.22F.23F.24F.25F.27F.28F.29F.32F.49F.61F.62F.63F.64F.65F.67F.68F.70F.71F.72F.73F.74F.75F.77F.78F.83F.84F.85F.86F.87F.88F.89F.97F2F22Main burner does not lightNeon 1 lit (No)neon 1 not litNeon 2 lit (No)neon 2 not litNeon 3 lit (No)neon 3 not litNeon 4 lit (No)neon 4 not litP.01P.02P.03P.04P.05P.06P.07Pilot does not lightPilot does not stay alightPump OverrunS.0S.01S.02S.03S.04S.05S.06S.07S.08S.10S.11S.13S.14S.15S.16S.17S.20S.21S.22S.23S.24S.25S.26S.27S.28S.30S.31S.32S.33S.34S.39S.41S.42S.46S.53S.54S.88S.91S.96S.97S.98S.99S.108S.109

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