Hot Cylinder - upstairs or downstairs ?

mad DIY

I'm about to have a house replumbed as part of a refurbishment. Having spoken to several plumbers / builders about the location of a hot water cylinder I'm getting different answers.
The house is two storey, cold tank in attic, and an unpressurised system. Some tell me in order to get proper hot water pressure the hot tank must be upstairs. But some tell me it does not matter, as the head pressure through the hot tank is dictated by where the cold water tank is. I'm confused Who's correct ? Thanks in advance for help with this.

danjo

Interesting question. I would think it would only depend on the position of the cold water tank.
If this were not so then I would expect poor pressure in upstairs bathroom taps (when hot water cylinder is upstairs). Will wait for the expert opinions on this one.

Joey the lips

Agree very interesting question cant wait to see the answer myself. For the benefit of the op

My hot tank, my sisters is upstairs but my fathers and my brothers is downstairs.

Benefits????? Storage above it upstairs no need to make space for it downstairs.

Pete67

Does not matter, the flow is determined by two things, firstly the difference in height between the water level in the cold water storage tank and the tap or shower head, and secondly the resistance to flow (pressure drop) created by the pipework. The location of the hot water cylinder does not make the least bit of difference as long as it is lower than the storage tank!

mad DIY

Pete67 wrote: »

Does not matter, the flow is determined by two things, firstly the difference in height between the water level in the cold water storage tank and the tap or shower head, and secondly the resistance to flow (pressure drop) created by the pipework. The location of the hot water cylinder does not make the least bit of difference as long as it is lower than the storage tank!

This version is the one I believe, having been relatively awake during Physics lessons when I was in school.

Adding in the theory of resistance of flow created by the pipework which I had not taken into account, then maybe it is best to have the tank upstairs after all to get best pressure upstairs as it minimises on the length of the pipework to the upstairs taps/shower. This possibly at the expense of a little lower pressure in the downstairs taps due to the longer vertical run to them, but which should be adequately compensated for by gravity due to being further below. Am I on the right track ?

Joey the lips

^^^^ WTF i like petes explination better if you said this to me I would be thinking sh1t 10k plumbing job!

slavetothegrind

mad DIY wrote: »

This version is the one I believe, having been relatively awake during Physics lessons when I was in school.

Adding in the theory of resistance of flow created by the pipework which I had not taken into account, then maybe it is best to have the tank upstairs after all to get best pressure upstairs as it minimises on the length of the pipework to the upstairs taps/shower. This possibly at the expense of a little lower pressure in the downstairs taps due to the longer vertical run to them, but which should be adequately compensated for by gravity due to being further below. Am I on the right track ?

Positively Joycian prose there:D

Really the issue is with hydraulic gradient.
http://www.blackwellpublishing.com/treloar/1405139625_4_002.pdf

Page 39 or so above will help, proper system design will ensure no problems.

You will find the above very useful reference, i was looking for something to illustrate my point and there is a free online version of a €30 text book!!!!

mad DIY

Thanks Joeclif, there's some interesting things in there.