Vacuum Relief Damper for CM2 and CA3 Boilers
The vacuum relief damper is very simple in design. When a vacuum occurs inside the vent system (as occurs with the Joukowsky effect) and the atmospheric pressure outside of the vent exceeds the tension of the spring, the spring compresses to open a flapper. As this flapper opens, air is allowed to enter the vent system which relieves the vacuum and prevents damage to the vent and to the boiler system. The relief damper is available [for our CM2 and CA3 boilers] in a range of 5 sizes to suit a variety of commercial gas boiler vent systems.