Open vented primary systems

Open vented primary systems

The feed and expansion cistern (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 open vent pipe (H), feed and expansion pipe (F) must rise continuously from the appliance.

The open vent pipe (H) must be at least 22mm dia.