I'm trying to supply 3 outlets in a shower from ONE output of a digital mixer. I want to be able to control the flow to each of the outputs individually and balance them as I need.

I've spoken to a number of technical support lines and their initial response has generally been "You can't do that", but with no explanation as to why it's a problem.

When pushed, one person suggested that the control circuit in the mixer MIGHT shut down the mixer if the outlet is constricted too much. The feeling was that it would probably reset itself eventually but it might take a long time and, potentially could cause damage to the mixer if it happened repeatedly. This seems plausible to me.

Does anyone have experience of this or could you give any real reason why manufacturers are telling people this can't be done?

  • 2
    More information is needed. Such as mixer model number and characteristics or a pointer to its data sheet. – Michael Karas Aug 30 '14 at 10:42
  • @Michael Karas - I can't find the exact model on Mira's site - but assume it's one of the ones on this page: mirashowers.co.uk/onlinecatalog/…. Do you think some mixers might allow it and others won't? – Lefty Aug 30 '14 at 12:15
  • First off.....I think your idea to feed three shower heads off one digital mixer is a bad idea. The main reason for saying that is because in all probability you would be unhappy with the results. The mixer is designed specifically with a particular show head and its flow control in mind. You try to pipe that off to three heads and the resulting flow out of each is likely to be pathetic. Keep in mind also that the piping to a typical shower installation may not even have the flow capacity to support three show heads. The added flow will create a pressure drop that may go (continued) – Michael Karas Aug 30 '14 at 21:45
  • (continued from above) below what even the Mira mixer can accept as the minimum input flow and pressure. I can see that your goal is to avoid the exorbitant cost of multiple mixers. However please consider this: With the state of affairs with fresh water supplies dwindling in many parts of the world products like Mira is offering should actually be banned and showers be made less desirable to spend time in as opposed to longer. – Michael Karas Aug 30 '14 at 21:50
  • @Michael Karas - thank you for your response. First off, I'm not trying to save money by having less mixers (but that was a good guess and a clever idea!) but I have a complicated reason for wanting to do this which everyone agrees with when I explain it. The alternative is that I have 2 entirely separate shower mixers in one wet room - with their own handset. I can see that the flow rate might be a problem due to the outlet of the mixer being a single 15mm pipe and this will be split between 3 outlets. In reality, it will only be split between 2 of them at any one time. (cont..) – Lefty Aug 31 '14 at 8:32

You could plumb a 3-outlet manifold feeding 3 individual shower flow controllers. You would end up with the single digital temp/flow controller upstream, then three separate single-handle shower flow controllers downstream.

I have seen a similar set-up, the temp. controller (mixer) is on the backside of the wall so employees only have access and water is kept tepid. Public users control only on/off and flow.

  • thank you very much for this information, it sounds very similar to what I'm trying to achieve. My plumber doesn't seem to have any problem with HOW to split the feed to 3 valves - I assumed he was just going to create a manifold using t-joints and pipe. It's mainly this attitude that I keep getting from manufacturers (and now Michael Karas here) saying that the mixer will not work properly or may be damaged if I stem the flow downstream. It sounds as though the example you've previously seen does this as a matter of routine, leaving it on all the time...? – Lefty Aug 31 '14 at 13:48
  • They turn it on at beginning of business daily, but it is not a digital mixer. Just standard mixing valve with an internal pressure-balance feature to prevent scalding. I am not sure if your digital mixer may have some sort of "time out" feature or something? – Jimmy Fix-it Aug 31 '14 at 13:52
  • That's what I'm afraid of. In practice, I think we can easily make sure that we never shut-off all 3 valves at the same time - but I'm sure there will be occasions when it happens and I obviously don't want it to cause damage to the mixer when that happens. By the way, sorry I don't have enough reputation to upvote your answer. – Lefty Aug 31 '14 at 14:26
  • @Lefty, no worries about the votes, just trying to help each other right? I would not worry about damage to the valve, it will have been designed to protect itself. My concern would be that it would turn itself off. – Jimmy Fix-it Sep 1 '14 at 2:59
  • Thanks @Jimmy. An interesting new bit of information as materialised today - see my own answer to my question. – Lefty Sep 1 '14 at 14:21

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