Function

The Temperature & Pressure Relief Valve, is a SAFETY CONTROL VALVE, which ensures that when the thermostat and / or energy cut out devices fails, the temperature of the water in a pressurised unvented water heater cannot exceed 99°C.

Operation

As the temperature of the water increases, the thermostatic relief probe in the valve expands and opens the valve seat before the water temperature exceeds boiling point at atmospheric pressure. Being below the critical temperature the water remains as water and is safely discharged through the drain pipe. With the valve in the open position, the pressure in the water heater reduces. When the pressure is below the incoming mains pressure, cold water enters the water heater and displaces the hot water through the open temperature relief valve. When the bulk of the hot water has been discharged, the cooler water causes the thermostatic probe to contract and the valve closes. The cycle of overheating and discharging will continue until the faulty controls are serviced.

Application

Installation of unvented storage water heaters. Australian Standard AS3500-4 and Hong Kong EMSD regulations requires that unvented storage water heaters be fitted with a temperature and pressure relief valve.

Main features

Individually tested and calibrated
Dezincification resistant
Sealed spring cavity (Dry Springs)
Automatic sealing
Non-resettable option available
Plastic coated temperature probe
Suitable for horizontal or vertical installations
Designed and manufactured in Australia

Installation

Storage Water Heater ...... Solar Water Heater

Approvals

Australia - Complies with AS1357.1
Hong Kong - WSD ref: (6) 10WWO3321/82xxxviii tj (25)
United Kingdom - WRC listed ref: 9406023