This safety device is also referred to as a Pressure Release Valve, Prv or Safety Valve and is a mechanical device that operates at a pre-set pressures. The most common pressure setting for these Biasi safety devices are 3 bar and once this pressure is reached the safety valve opens. Biasi will not allow their boilers to work above certain pressures as they view this as dangerous so they ensure the boiler can't operate above these levels by having the pressure relief valve fitted within the boiler. The pressure relief valve is connected to a discharge pipe that takes pressure away from the boiler in the form of hot water and releases it to a drain.
Biasi BI1441101 Inovia Advance PRV

Part: BI1441101

Price: £17.07
Biasi BI1001112 Prisma 24S Safety Valve

Part: BI1001112

Price: £17.62