Lifebreath CAF-02-MB Benutzerhandbuch

From the aspect of delivery of domestic hot
water and space heating, the Open and Closed
systems operate the same. A system becomes
closed when a backflow prevention valve or
check valve is installed in the cold water piping
upstream of the water heater. A backflow 
prevention valve will prevent the pressure created
when water is heated in the water heater, from
being relieved into the cold water system.

Therefore, an expansion tank (or equivalent
device) may be installed as part of any closed 
system. The operations of the valve and 
expansion tank are discussed later in this 
section of this manual.