Open vented primary systems

The cold feed (F) and expansion tank (E) must be positioned to provide a static head (S) of at least 1 metre above the highest point in the heating system to the water level in the expansion tank (E).

The heating vent (H) and cold feed pipes (F) must rise continuously from the appliance.

The heating vent pipe (H) must be at least 22mmØ and 350mm above the waterline in the cold feed and expansion tank (E).