Wall Joist Hangers and Support for Cold Water Storage Tank

[zerodefect]

I live on the ground floor of a two-bed maisonette (built 1969). Situated in the bedroom cupboard is the original cold water storage tank. It goes without saying that is needs replacing.

I was thinking about moving the storage tank from the bedroom cupboard into the hallway/entrance cupboard. As it stands currently, the hallway cupboard also contains the hot water cylinder (with immersion heater). If I relocate the cold storage tank and position above the hot water cylinder, would I need to channel the walls for the supporting wood beams or could I resort to using heavy duty wall joist hangers with wall bolts? I'm very aware of the weight of the water storage tank once full. Some joist hangers (face fix) I've seen suggest a capacity of over 5kN - quite a load.

Gavin.