What is "head" and what isn't "head"

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On the attached PDF file, which system will work best and why?
Or will they both work the same.... and why?

When I say "best" I mean flow at hot tap and pressure at hot tap in each system.

No wise cracks about lack of feed to the cold tank, no overflow etc.... it is diagrammatic.. :)

TIA... Cheers
 
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Both the same.

Assuming pipe sizes are the same then then both presure and flow will be the same...unless of course you haven't told us something important about your homework question? :LOL:
 
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I won't rise to your cheek about homework...

That is my thought exactly... so why do several "plumbers" say "Ooh no,... don't put your hot tank right up under the cold water feed, there will be no head to feed the hot tank"

Maybe these "plumbers" need to go back to school and do some homework??

Unless someone knows something I don't know! I am open to reasoning.
 
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They never covered this stuff at school when I went. There was "Domestic Science" but it was cooking, and only in girls' schools. Stupid, they should cover the basics of how houses & simple tech stuff actually WORKS.

In plumbing though there's often something going on which is not at all obvious as soon as things get away from the very simple. Nothing is quite as simple as you've drawn it, so the people you spoke to may have had some valid thought in mind.

That's not to say that some plumbers aren't as thick as grannie's bedsocks.
 
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My standard "grannys socks" question for plumbers when they come through the door is "If I run a 28mm pipe from the tank in the loft and put a nozzle on the end aka a tap, and an 8mm pipe from the tank in the loft to the another nozzle.... which will spray the water the furthest... or put another way... which will have the greatest pressure at the outlet.

The answers are staggering sometimes.
 
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Careful, to answer that you'd have to define half a dozen things ;)
The answer could be , for practical purposes, anything between "huge difference" and "no difference".
As long as they didn't say it would be better with the thinner pipe..... :rolleyes:
 
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I start to worry when they hesitate and either scratch their heads or hold their chins and say questioningly "The bigger one?"
 
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Charlie Mullins, who runs the very successful Pimlico Plumbing, made 2 apprentices repipe a whole fountain (on TV) with thinner pipe because according to him the water goes faster in thinner pipe so it would spray further.

He was wrong, and all sensible plumbers took the ****, but there is a some truth in what he said, even for under a static head.
>>"Discuss"<<!

In plumbing perhaps more than many other areas, if something looks simple then there's a little bit more to understand :D :LOL:
Judging when to bother to argue it out is the hard bit.
 
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Haha... funny as....

Has he opened an office in Hartlepool by any chance?

I wont even start to mention Reynolds numbers!!

Or the Colebrooke or the Haaland equations.... or in the UK the Hazen-Williams equation I believe.

I know of them... I don't know how to apply them tho.
 
L

longdogs

That is my thought exactly... so why do several "plumbers" say "Ooh no,... don't put your hot tank right up under the cold water feed, there will be no head to feed the hot tank"

Maybe these "plumbers" need to go back to school and do some homework??

Maybe they just don't like you. You seem to know all the answers anyway :rolleyes:
 
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B is better because you get hot water out the tap sooner! i.e the leg between tank and tap has less volume.

Nozzle
 
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Only if there are enough folk in Hartlepool who want to pay £100 a half hour while the lad puts all the dust sheets round the entire house, or having got you to sign "time started" goes off to find a parking space.

You don't need them equations. They don't apply. You don't have perfect pipes. You DO need the experience to know what works, and maybe a few charts, once in a blue moon. It's a garden tap not a chemical pipeline.
So, sure a tad of common sense and simple science, but more importantly, whether burrs on pipes, or stopcocks, or gate valves, or bends, or the regulation check valve, actually affect whether it'll work WELL ENOUGH that the plumber gets paid!.
 

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