Surrey V Warix Flange


31 Aug 2004
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United Kingdom
I have bought a new Aqualisa power shower (1.5 bar) and already have a Surrey Flange fitted to the hot water cylinder. Aqualisa does not recommend using the Surrey Flange as they say it restricts the flow. They recommend the Warix Flange instead.
How much affect on the flow rate would the Surrey Flange actually have? Should I replace the Surrey with a Warix or is it not really worth the bother? It would involve a change of the pipe layout.
They also say copper pipe is better than plastic because again plastic restricts the flow. By how much? Would it really make such a big difference to the "power" of the shower?
Any info appreciated.
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DJS said:
They also say copper pipe is better than plastic because again plastic restricts the flow. By how much? Would it really make such a big difference to the "power" of the shower?
Any info appreciated.

I would think very little difference. The wall thickness of plastic pipe is greater, thus the internal diameter of the pipe is slightly less. But it is probably amounts to a few % of the area.

The copper pipe is rigid, whereas the plastic pipe (when hot) may sag slightly. Again, this will make a tiny amount of difference.

The only real issue I can see is that copper pipe can be bent to form sweeping bends down to quite small radii, but plastic pipe can only be bent over significantly larger radii. Hence elbow fittings would be required in places. This would be the main cause of flow restriction, elbows are a no-no where optimum shower performance is required.

If you can ensure that any required bends are of sufficient radius to allow plastic pipe without elbow fittings, then I reckon the difference would be negligible.

EDIT: I can't comment on the flange, I know nothing of flanges other than Surrey.
I have found from my experience that, following manufactures instructions overide everything. if the manufacture of the shower recommeneds fitting a certain type of flange then go with the manufacture as they try and test everything for the consumer.
Look at the size of the hole in the Surrey flange (tho it does depend on the size of the thread).
Look at the rather smaller sized hole in the shower hose, which has to take all the flow not just the hot.
Consider the length of the restriction in each case. Draw your own conclusion? ;)

Bloke doing a Cuprofit demo, who knew his stuff, told me that they'd tested their pex pipe against copper. (They make both).The pex was less resistive in spite of being smaller internal diameter, becasue the plastic is more slippery from the water's point of view (as it were!).

I prefer Essex flanges - fitted in 3 minutes!
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Thanks chaps,
I hope not to use any elbows in the pipe runs which will be quite short so I may well use plastic.
The shower instructions don't actually state if any type of flange can or cannot be used, its just that someone else who contacted Aqualisa was told the Surrey Flange was not recommended.
Seeing as the Surrey Flange was already installed I think I will try it and see how it goes.
Cheers once again.
I wouldn't worry to much about the odd elbow either. Depending on where you look you'll see they have the resistance of half to one metre of pipe of the same size. You wouldn't expect a couple of metres of pipe to do a lot.
As a matter of interest, how do you fit an Essex Flange?
Drilling the hole in the side of the cylinder worries me a bit.
A holesaw the right size. ( 1 5/16 for a 15mm pipe IIRC.) Then you fix a bit of pipe to the body of the thing so you can handle it, poke it through, wind a washer through the hole, put the big washer and nut on, worry, undo it again and put some LS-X on, and do it up again.

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