'Celerity' gas instantaneous water heater with wall bracket

'Celerity' gas instantaneous water heater with wall bracket, manufactured by Fletcher, Russell & Co. Ltd, Warrington.

Instantaneous gas water heater (sometimes called 'geysers' heated water only when a hot tap was opened, rather than storing hot water in a tank. The advantages included instant hot water availability, less fuel wasted keeping water hot all day, a compact design and unlimited hot water provided the gas supply and water flow continued. However they came with risks. Poor ventilation could allow combustion gases to accumulate which could lead to exposure to deadly carbon monoxide. The temperature could be unstable. if the water flow fluctuated, the outlet temperature could swing from cool to dangerously hot.