AVG Hot Water Expansion PTR Valve 15mm — Green cap, 1000 kPa
Check the cap colour before you order. AVG PTR valves are colour coded by pressure rating: green = 1000 kPa, blue = 850 kPa. Fitting the wrong rating causes the very dripping you are trying to stop.
The Pressure and Temperature Relief valve (PTR) relieves the increase in pressure caused by water expansion during the normal heating cycle, by releasing drips of hot water to the drain line. Should the electrical temperature cut-out device cease to operate correctly the water will overheat, and the temperature probe will then open the PTR valve and discharge hot water to the drain line.
It is recommended that an ECV be fitted to the cold water supply line. This relieves cold water rather than hot during the heating cycle, saving energy and extending the life of the PTR. Some local governments make it mandatory to fit an ECV in the cold water line.
PTR and ECV valves are safety valves and should be replaced every 4 years.
Inlet pressure control
High pressure may cause excessive discharge and premature failure of the operating relief valve. Maximum water pressure usually occurs overnight, at the time of lowest water usage. On any mains pressure water heater installation, if the water pressure exceeds 80% of the nominal set pressure of the operating relief valve, a Pressure Limiting Valve must be fitted to the cold inlet. If a cold water expansion control valve is fitted it will have a lower set pressure than the PTR valve, and will therefore become the main operating relief valve.
Not sure which one you need? Email sales@solarhotwaterparts.com.au a photo of the valve in place with the cap visible, and we will confirm the rating before you order.