Technical Booklet P Sanitary Appliances Unvented Hot Water Storage and Scalding·Page 12·2.1
Minimum safety devices for unvented hot water storage systems
Unvented hot water storage systems must incorporate at least two independent safety devices in addition to any temperature control thermostat to minimize dangers from excessive pressure.
To minimise the danger from excessive pressure, unvented hot water storage systems should incorporate a minimum of two independent safety devices in addition to any thermostat provided to control the desired temperature of the stored water.
The selection of safety devices should take account of the physical location of the devices, and the design, configuration, location of components and performance characteristics of the system to which they are attached.
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