Combination tank and shower

[petearm]

Hello all,

Have just moved into a flat with a 1075 by 450 direct combination hot water cylinder. There is no shower since there'd be insufficient head from the tank outlet.

I was planning on fitting a small negative head pump (18 litres/min) to the hot water tank outlet. However, the cold water tank is only 20 litres so I was also planing on putting in a ball cock with as large an orifice as possible so that the water can be replenished quickly enough to provide a decent shower (or alternatively fit two independent ball cocks).

I've seen a similar setup with combination tank of the same size which worked but the pump "ran dry" occasionally when the hot water was allowed to run for too long. If this happens to my system, I was planning on putting an orifice up stream of the pump to restrict the flow and prevent this happening whilst still allowing the shower to function.

I've thought about going for an unvented system but am not keen on the expense and maintenance that this would entail so have decided against this....

Does anyone have any other ideas or comments?

 

[leakydave]

I think a mains-fed electric shower is your best bet IMHO.

 

[seco services]

I wouldn't recommend it.
As said fit a electric shower or replace the cylinder and larger header tank.

 

[petearm]

I'd agree with you on the electric shower point, however we're on an economy 7 tariff and use the shower first thing so want to be able to use the water from the tank.

Have also thought about installing a larger tank, however, the problem is there are only a limited range of combination tank options none of which seem to have the "115 litre" cold storage capacity which is recommended by most pump instruction manuals. Also, the one's with a bigger storage tank seem always to have a larger hot water section which would be unnecessary and wasteful for the amount we'd use. Finally there doesn't seem to be enough room in the airing cupboard for two seperate tanks...