Vokera Mynute He fault codes

3 codes from the Vokera manual for the Mynute He gas boiler. Pick one for what it means, the likely causes and where to start.

Code	What it means
10	Gas supply/flue system/polarity fault
AL10	Ignition failure/not flame sensed, condense sensor activated
AL79	Flow temperature too high, or temperature differential between primary and return too high