Operation:

• As water flows through the NEFA Pressure Limiting Valve (PLV), the pressure in the outlet chamber acts to close the jumper on to the valve seat, while the control spring opposes this closure.
• As the outlet pressure rises to the set pressure of the PLV, the jumper closes tightly on to the valve seat and shuts of any further flow.
• When a tap is opened, a pressure drop occurs in the pipes through to the outlet chamber of the PLV.
• This fall in outlet pressure causes the spring to push the jumper off the valve seat, opening the valve and allowing water to flow.
• Due to the design of the water-way in the PLV, the inlet pressure does not influence the jumper, therefore variations in inlet pressure have no effect on outlet pressure.

Installation

• NEFA valves should always be installed by a licensed plumber in accordance with National Plumbing and Drainage Code AS/NZ3500.4.
• The installation must also comply with any Local Authority requirements and the water heater manufacturer’s requirements.
• A PLV should be installed if supply pressure is greater than 80% of the ECV (if fitted) or PTR pressure rating as stated in the table below.
• Suitable for vertical or horizontal installation.
• Install with the direction of flow in-line with the arrow on the valve body.
• Install the PLV at the entry to the property or after the Non Return Isolation Valve.  
• The valve should be installed where it can be easily accessed.
• Ensure that sealing materials, e.g. thread tape or thread sealing paste, do not intrude into flow passages as this could cause obstruction to flow and failure of the valve.
• The valve must not be buried in the ground or installed in a situation where it could be subject to freezing.
• Never expose valves to a torch flame or heat, as it will destroy the seals and sealing parts.

REFER TO TECHNICAL DRAWINGS AND IMAGES FOR TYPICAL INSTALLATION DIAGRAMS.