Shortening dhw recovery period

[Lazy Beetle]

Hello all,

I've always fitted the flow pipe from the boiler to the top connector on the dhw cyclinder. In fact most literature I read on the subject suggests the same, that is until I read the R.D. Treloar book on plumbing. It's suggested (p124) that a shorter recovery time can be obtained by reversing these connections, i.e. flow in at the bottom and return at the top.

Anyone ever tried this? Pros and cons?

Thanks

[IMM]

The Treloar book I don't rate at all. He is taking balls. The faster recovery rate is connecting the top coil connection to the flow. When you have it this way you will have usable hot water much quicker, not a full cylinder but water to fill sinks, etc.

Reversing the flow and return will give "slightly" more hot water in the cylinder.

If you want a real quick recovery buy a quick recovery cylinder (Telford Typhoon @ £99 from Travis Perkins).

[IMM]

I'm not in position to review the books. Of course the books can be wrong or right, leading or lagging relative to current practice.

IN the old days of 'gravity' (i.e. thermosyphon convection) moving the primary water around then certainly the hot went in at the top, so this became the norm. In fact it carried on being the norm.

I have certainly experienced no problems by connecting the flow to the base - and I did that in my own home and at several sites elsewhere.

I expect that it might lead to a slightly larger capacity of stored HW with flow at the base. Especially since the modern faster coils now exit at the middle of the cylinder.

I think it is a reasonable assumption to imagine that any HW produced wells to the top of the cyl. - of course it will give off some heat to the rest of the cyl. contents. Mostly experience shows that the 'thermals' remain intact as they well up, since you can get usably HW very soon after applying heat by any method.