Self-priming devices for indirect domestic water heating systems and the use of such devices.

摘要

Self-priming devices for indirect domestic water heating systems which have a primary heating circuit including a heat exchanger (20) which heats domestic water in a secondary circuit, both circuits being fed with cold water from a common source. The self-priming device (1) has axially disposed upper and lower chambers, the upper chamber (4) being connected in the secondary circuit and the lower chamber (5) being connected in the primary circuit. The device acts as expansion and contraction chambers for both circuits and isolates the water in the primary circuit from the water in the secondary circuit during operation of the system. An auto vent valve (11) is provided adjacent the bottom of the lower chamber (5) to provide for inital filling of the primary circuit and for replenishing the primary circuit from time to time through the secondary circuit. The volume of the lower chamber (5) is at least 4 to 4.5% of the total water content of the primary circuit.