In an earlier contribution to this discussion,
BigWallop wrote:


So you're saying it would be better if the cold supply was direct
from the mains?

I said no such thing! The shower pump must have equal pressure on its hot
and cold feeds - so they must both be gravity feeds from the cold tank

Or is your own contradiction a part of not
understanding the workings of creating a head of water to a shower
head?

I understand the Physics of it all perfectly - but I'm not convinced that
you do.

You say that the cold water storage tank may empty if the shower used:

" With a power shower going full tilt, you will potentially be
removing water
from the cold tank faster than the mains supply can replenish it."

Then you say to take yet another cold water supply from the cold water
storage tank:

I'm saying that *all* of the water going to the shower is coming from the
cold tank - the cold going directly, and the hot going via the hot cylinder

"The take-off point for the cold feed to the hot cylinder - which in
turn
pushes hot water out of the cylinder to the shower pump - needs to be
*higher* up the cold tank than the take-off point for the cold feed
to the shower pump."

Or am I missing your point here?

YES!!


A shower pump isn't a massive taker of water, that's why they are only
supplied with narrow bore pipes.

A decent power shower will deliver 15 litres or more per minute. Many
domestic cold supplies can deliver little more than 10 litres per minute -
so with the shower going full tilt, the level in the tank will go *down*
even if no-one else in the house is using any water.

It's important that the shower doesn't run out of cold water before it runs
out of hot - hence the need to have to cold feed for the shower at a lower
level in the tank than the hot feed.

I cannot explain it any more clearly!

If you *still* can't understand go and ask all the Little Wallops and Middle
Wallops in your family - maybe they can explain it better!
--
Cheers,
Set Square
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