RMC Pressure and Temperature Relief valves ensure that the temperature of the water in a pressurised unvented water heater cannot exceed 99°c in the event that the normal thermostatic controls fail.
Maximum temperature (all models) 99 degrees C
Rated Capacity (AS1357.1): DN15mm - 10 kW, DN20mm - 46kW
Standard Pressure Settings Available 500 kPa, 700kPa, 850kPa, 1000kPa and 1400kPa
Size Width (W) Height (H) Outlet (O)
15mm 68mm 98mm DN15
20mm 71mm 99mm DN20
Body - Cast gunmetal/Brass
Internal Parts - Brass and stainless steel
Seat Disc - Silicon
Pressure Spring - Stainless steel
Piston - Acetal/Brass
The Pressure and Temperature Relief (P&T Relief) Valve should be installed at the heater. System inlet pressure should be no higher than 80% of the set pressure of the P&T Relief Valve.
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.
Auxiliary pressure relief device - prevents pressure building up in the event of a blockage In the drain line.
Female BSP thread on outlet thread - prevents incorrect installation to the tank.
Plastic coated temperature probe - prevents electrolysis of the probe outer casing.
Suitable for horizontal or vertical installation - valve designed to work effectively in either orientation.
Individually tested and calibrated - every valves is tested to ensure higher quality and performance.
15mm Models: HT501 (500kPa), HT503 (700kPa), HT505 (850kPa), HT507 (1000kPa) and HT511 (1400kPa)
20mm Models: HT701 (500kPa), HT703 (700kPa), HT705 (850kPa), HT707 (1000kPa), HT711 (1400kPa)