22 -> 15mm shower, length?

[Simon Avery]

Hello All

Installing new pumped shower. Have lovely fat 22mm swooping runs of speedfit with only one T off for the bath.

Somewhat disappointingly, the thermostatic shower unit only has inlets for 15mm, so I can't give full flow to the head. :/

So, my question is:

Do I bother putting 22mm up the wall and reduce at last possible point, or do I reduce at the floor and put 15mm up?

The latter is easier and less disruption, but would it impact the shower performance noticably, especially given that the outlet connection from the mixer is 15mm also?

(Pump is 3-bar btw, single shower head not a bodywash system)

[Christian McArdle]

Use 15mm. It is easily large enough for a pumped power shower.

Christian.

[Grunff]

With a pumped system like this you'll never notice the difference (unless a *very* long run).

[Huge]

I plumbed our power shower in 15mm, then read the pump instructions(!) which said to use 22mm up to the ends, then switch to 15mm for the final connections. Since the pipework was buried in walls by this point, I wasn't changing it. It works fine and has done for 7 years.

So, like the man says, use 15mm.

[Andy Hall]

You're only going to be talking about a metre to a metre and a half I guess, in which case it wouldn't be a problem.

It is worth checking the hose from the valve to the head assuming you have a hose. Some have quite a narrow bore and that certainly makes a difference.

.andy

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[Simon Avery]

Hello Grunff

Only up from the floor,