The answer in two lines
An exposed (wall-mounted) mixer sits on top of the tiles and has a diverter that switches water between the bath spout and the shower outlet; an automatic diverter returns the flow to the spout when you turn off. Before buying, check the connection type, centre distance, hot and cold sides and suitable water pressure, all from the maker's installation sheet for that model.
Unsure whether to choose an exposed mixer, a concealed one or a shower column? This guide from Tawredaat (توريدات), an Egyptian supplier of electrical and finishing materials in Cairo and Giza, explains how an exposed mixer with an automatic diverter works, how to choose it and the order of installation, using the sources listed at the end.
A note on numbers: the only figures here come from named makers (Hansgrohe, Plumbworld) for specific models as examples; other models may differ. Where we found no published figure we do not state one; read the sheet for your model.
What is an exposed bath-shower mixer with an automatic diverter?
An exposed mixer has its body on the wall face, in view, not inside the wall. Aqualisa says that with an exposed shower "the valve is mounted on the tiles and is in view", while a concealed shower places the valve and pipework beneath the tiles. A diverter is a valve that switches water between the bath spout and the shower outlet. Per Inspect and Test, water goes to the spout by default; engaging the diverter closes the spout route so water goes to the shower; turning the diverter off or shutting the water off returns it to the spout. Hansgrohe describes its exposed Rebris E as having a "diverter with automatic resetting".
| Outlet | What it does | When you use it |
|---|---|---|
| Spout | Default route: water flows from it | Filling the bath or basin |
| Shower outlet | Active when the diverter closes the spout route | Showering with the hand shower |
How does exposed differ from concealed and from a shower column?
| Type | What the sources say | Note |
|---|---|---|
| Exposed (wall-mounted) mixer | Aqualisa: valve mounted on the tiles and in view | Suits a bathroom that is already tiled, if the wall connections are ready |
| Concealed mixer | Aqualisa: valve and pipework behind the tiles, suits a minimalist look. A body in the wall and a visible trim (see our concealed mixer guide) | Must be prepared before tiling |
| Shower column | Crosswater describes a wall-mounted shower system with visible pipework and valve; its dual-outlet valve switches between the overhead and hand shower | Read more in our rain shower vs regular shower guide |
- ✔ Exposed: the body is on the tiles and in view (Aqualisa).
- ✔ Concealed: valve and pipework behind the tiles (Aqualisa), so it is prepared before tiling.
- ⚠ Column: a shower system, not a replacement for a bath spout; check the sheet if you need to fill a bath.
What should I check before buying?
1) Connection type and centre distance
An exposed mixer connects to hot and cold inlets in the wall, and their spacing must match the mixer. Published examples: Hansgrohe lists 150 ± 12 mm centre distance with S-connections for its Rebris E and Ecostat exposed mixers, and Plumbworld says inlet pipework should be at 150 mm centres "as a guideline only, so measure your product before installing". So 150 mm is a common figure, not a universal rule.
2) Hot and cold sides
Plumbworld says the hot inlet is marked red and the cold blue, and you should check those marks before fitting. Always confirm the required side in the installation sheet; we do not assume it.
3) Water pressure
Pressure comes from the model sheet. Published examples: Hansgrohe Rebris E lists minimum operating pressure 1 bar and maximum 10 bar; Plumbworld recommends 0.5 to 5 bar for its products, and for tank-fed low-pressure installs the outlet should be at least 1.8 m below the cold tank underside. These apply to those models only.
- ✔ Compare your supply or pump pressure with the minimum in the model sheet.
- ✔ The Sarrdesign listing says "low-pressure operation" in its title only; we cannot confirm any pressure value.
- ⚠ Do not buy on the claim that it works at any pressure; ask for the figures in the sheet.
How is an exposed mixer installed? Order of work
General order per Plumbworld, as an example and not a replacement for your model's sheet:
- ✔ 1. Flush the pipework: run hot and cold for a few minutes, then shut off.
- ✔ 2. Set the inlets at the required centres (150 mm for that product).
- ✔ 3. Offset connectors: wrap PTFE tape and fit them to the inlet pipes.
- ✔ 4. Cover plates and washers, then fit the mixer.
- ✔ 5. Check hot and cold match the marks.
- ✔ 6. Test for leaks and retighten if needed.
- ⚠ Use a qualified plumber and the maker's sheet; Hansgrohe says to always observe the supplied installation information.
Wall-mounted bath-shower mixers at Tawredaat
Currently available: Roca Atlas Wall-Mounted Bath and Shower Mixer with Automatic Diverter, Roca Naia Wall-Mounted Single-Lever Bath and Shower Mixer - Chrome (A5A0296C00) and Sarrdesign Wall-Mount Bath and Shower Mixer with Automatic Diverter - Chrome (SD1141). Our product pages give only the title: the Sarrdesign title includes "for low-pressure operation", and that is all we say about it. Roca's sheet for the Atlas (A5A0290C00) refers to an Installation Handbook with the same reference, which is the place for spacing and connections. Browse all bath and shower mixers.
Frequently asked questions
What is an automatic diverter?
A valve that switches water between the spout and the shower outlet; the automatic type returns to the spout when you turn off (Inspect and Test; Hansgrohe: diverter with automatic resetting).
What is the centre distance of an exposed mixer?
150 mm is a common published figure (Hansgrohe: ±12 mm; Plumbworld: guideline only), but confirm in your model's sheet.
Can I fit an exposed mixer where a concealed one was?
Possibly, if the wall connections suit it, but a concealed mixer has a body in the wall, so the change may need pipework changes decided with a plumber.
What pressure do I need?
There is no single figure: examples are 1 bar minimum for a Hansgrohe model and 0.5 bar for Plumbworld products, so read your model's sheet.
How do I tell hot from cold?
Plumbworld: hot inlet marked red, cold blue; check these and the sheet before fitting.
Do you deliver to every governorate?
Tawredaat delivers in Cairo and Giza only.
Choosing a bath mixer?
See bath and shower mixers at Tawredaat, with delivery in Cairo and Giza.
About Tawredaat: Tawredaat (توريدات) is an Egyptian supplier of electrical and finishing materials, serving homeowners, companies and contractors in Cairo and Giza. Questions? See our FAQ.
English summary: An exposed (wall-mounted) bath-shower mixer sits on the tiles and uses a diverter to switch water between the bath spout and the shower outlet; an automatic diverter returns flow to the spout when you turn off. Before buying, check connection type, centre distance (150 mm is a published example, not a rule), hot and cold sides and the pressure range, all from the maker's installation sheet.
Sources
- Plumbworld, Deck / wall mounted bath shower mixer valve installation guide (150 mm guideline, 0.5-5 bar, red/blue, install order) — plumbworld.co.uk/documents/deck-wall-mounted-bath-shower-mixer-valve-installation-guide.pdf
- Hansgrohe, Rebris E single lever bath mixer for exposed installation 72450009 (150 ± 12 mm, 1-10 bar, diverter with automatic resetting) — hansgrohe.com/articledetail-rebris-e-single-lever-bath-mixer-for-exposed-installation-2-ticks-72450009
- Hansgrohe, Ecostat thermostatic bath mixer for exposed installation 13112000 (150 ± 12 mm) — cdn.shopify.com/s/files/1/2780/7696/files/13112000-new.pdf
- Inspect and Test, Shower diverter guide — inspectandtest.net/guides/shower-diverter/
- Aqualisa, Concealed vs Exposed Showers — aqualisa.co.uk/blog/concealed-vs-exposed-showers/
- Crosswater, Union exposed shower column (sanctuary-bathrooms.co.uk) — sanctuary-bathrooms.co.uk/crosswater-union-matt-black-exposed-shower-column
- Roca, Wall-mounted bath-shower mixer A5A0290C00 product sheet — eg.roca.com/roca-services/productSheet30/EG/en/A5A0290C00/
- Tawredaat product pages (title only) — tawredaat.com/collections/bath-shower-mixers
