Observation:

This boiler is equipped with a built in frost protection system.
With CH & DHW or CH only selected, when the boiler temperature falls below 5°C the boiler will fire until a temperature of 30°C is reached.
If DHW only is selected, when the boiler CH temperature falls below 5°C the boiler will fire until a temperature of 30°C is reached. When the boiler DHW temperature falls below 5°C the boiler will fire until a temperature of 7°C is reached.
With the aid of a temperature probe if necessary determine whether the area in which the boiler is located is cold enough to activate the boiler's frost protection.