Open vented systems are systems where the outlet of the water heater is open to the atmosphere. Such systems allow expansion of heated water to be accommodated within the open vent. Wetback and push through systems are examples of open vented systems. Open vented systems are generally fed from either a supply tank or a pressure reducing valve.

Because water expands when heated, the extra water must be accommodated. A vent pipe provides for the escape of air (and steam if produced) and for the expansion of the water. If a pressure-reducing valve is installed then the vent pipe has to take all the extra volume of water and may overflow.

There are a number of low pressure systems including tank fed systems and pressure reducing valve fed, which uses mains pressure water and feeds to a low pressure storage tank through a pressure reducing valve.

Talk to us about an open vent low pressure heating system for your home.