The Seima 500 Series plate
This page lists the Seima 500 Series flush plate, a rectangular wall mounted plate for a Seima in-wall cistern. It has one larger button for a full flush and one smaller button for a half flush. The listings describe pneumatic buttons that need only a light touch, concealed fixing, and easy access to the cistern through the plate if it ever needs maintenance. The plate is ABS plastic and measures 236mm wide, 152mm high and 8mm deep. It is listed in matte white, matte black, brushed nickel, gunmetal, brushed gold and chrome.
Which cistern it suits
The listings say the plate suits all Seima in-wall cisterns. The Seima product page for the pneumatic plate is narrower and names four: the InWall C100 and C101 for floor mount pans, and the C200 and C201 for wall hung pans. It says the pneumatic plate suits pneumatic cisterns. Confirm the cistern behind your wall before you order. The plate is sold on its own and button options are sold separately, so assume nothing else is in the box.
The Seima in-wall system: four cisterns, two actuations
The Seima data sheets, version dated February 2025, describe an in-wall toilet system built on cisterns of two thicknesses and two actuation types. The C100 and C200 are 80mm thick and slim, made for a standard wall. The C101 and C201 are 130mm thick and made for a nib wall, which the sheets call an undercounter design. The C100 and C101 suit a floor mount pan, while the C200 and C201 come with a frame and suit a wall hung pan. All four work with pneumatic buttons.
A mechanical pair also exists: the M100 for a floor mount pan and the M200 with a frame for a wall hung pan, plus an M201 for a nib wall. These are operated through mechanical flush buttons. The listings on this page are the pneumatic Seima 500 Series plates, so they belong with the C series.
Why the actuation must match
The data sheets are specific. The M100 and M200 sheets say the cistern is compatible with Seima mechanical flush buttons, and the C101 sheet says it is compatible with Seima pneumatic flush buttons. The C100 and C200 sheets say they are compatible with the full range of Seima flush buttons. The Seima Modia wall hung sheet draws the same line when it lists mechanical and pneumatic cisterns under separate order codes.
So find out which kind of cistern is behind the wall before you order a plate, because the two actuations work differently. A Sydney Bathroomware guide to flush plates says pneumatic plates move air through hoses from the buttons to the valve, which is why the cistern can sit away from the plate.
Front access and top access
Where the plate goes depends on the wall. In a standard wall, the C100 and C200 sheets put the flush button plate on the wall above the toilet pan, which they call front access, and say the cistern can be serviced through that plate. In a nib wall, the C101 and C201 sheets allow the plate either on the wall above the pan for front access, or on top of the nib wall for top access. They also note that the C100 and C200 can be used in a nib wall.
The installation guide for the C200 adds that its instructions show the plate fitted for front access, and that a remote access plate has its own instructions. Settle the plate position with the plumber and the joiner before the wall is lined.
What the sheets say about servicing and condensation
Every cistern sheet makes the same two claims. The cistern is fully insulated with anti-condensation foam to prevent moisture escape, and the design lets it be serviced through the flush plate. For a wall hung installation the frame is listed as powder coated galvanised steel. The sheets state that installation shall be in accordance with AS/NZS 3500, and the C200 installation guide says a licensed plumber must install the cistern.
Since the plate is the way in for servicing, it needs a fixing that lets it come off again. The Seima 500 Series listings say the fixing is concealed and the cistern is reachable through the buttons.
The Modia wall hung pan and its cisterns
The Seima Modia wall hung data sheet describes a rimless pan with a Vortex Flush and a minimalist shape that sits flat against the wall, in white vitreous china with a P trap. It comes with a quick release, soft closing seat with stainless steel hinges, in a slim or flat shape made of thermoset UF with a silk finish. It carries a 4 star WELS rating at 4.5 and 3 litres. The sheet says to order the in-wall cistern and the flush plate separately, and that the pan suits an in-wall cistern with a frame. It works with mechanical and pneumatic cisterns. The M200 and C200 are listed at 80mm for a standard wall, and the M201 and C201 at 130mm for a nib wall. The plates here are the flush plate part of that order.
Seima colour buttons and hinge covers
A separate Seima sheet, version 9.0 dated February 2026, covers colour toilet flush buttons and seat hinge covers. Seima toilets come with chrome flush buttons and stainless steel seat hinge covers as standard. The colour parts are extras fitted in place of the standard ones, and the hinge covers are sold as a set of two. The sheet lists six colours: brushed nickel, gunmetal, brushed gold, brushed bronze, matte black and matte white. It sorts the hinge covers by seat type into Deluxe or Classic, Slim and Flat, each with its own order code, so the right set depends on the seat on the pan. These parts are for the toilet, not for the in-wall plate, and the sheet says they are available for selected suites, including the Arko, Modia, Limni and Syros.
The Flush Plate 500, pneumatic and mechanical
The Seima Flush Plate 500 data sheet, version 10.0 dated February 2026, describes a push button plate for in-wall toilets with pneumatic or mechanical actuation. It is ABS plastic, 236mm wide, 152mm high and 8mm deep, and the sheet calls it easy to install and service. Seven finishes are listed: brushed nickel, gunmetal, brushed gold, brushed bronze, black matte, white matte and chrome. Pneumatic and mechanical plates have separate order codes, and the mechanical version is called the Flush Plate 500M. The plates on this page are the pneumatic version, so they suit the C100, C101, C200 and C201 cisterns, and the 500M is the one for the M100, M200 and M201.
That split is the most useful thing to know before you order. The two versions look the same on the wall and share a size, and the pneumatic listing says it suits pneumatic cisterns. A pneumatic plate will not work on a mechanical cistern, and the reverse is also true. Ask the plumber to read the cistern model from the installation paperwork or from the cistern itself, then match the plate version to it.
What the installation guide asks of the plumber
The installation guides for the C100 and C200 run to seven or eight pages. They say a licensed plumber must install the cistern, and that the dimensions from the finished floor level to the pan inlet and outlet are in the pan specifications. They show the flush plate fitted for front access, with a separate instruction for remote access. One note matters for the wall around the plate: the flush pipe must be fixed securely to a nogging so it does not come away from the cistern when the pan is fitted.
Every data sheet carries the same cleaning line: clean with a damp cloth, and do not use abrasive cleaners, liquids or pastes. That is the maker's care instruction for its products, and it suits the plate as well.
Raised buttons and remote placement
Seima also lists a Flush Plate 300 with raised buttons, in chrome plated metal, 232mm wide and 148mm high, with a plate depth of 4.2mm and a button depth of 20mm. Its data sheet says the pneumatic push button system allows flexible placement of the flush plate. That plate is not on this page, but it shows what pneumatic actuation allows: the button does not have to sit above the cistern. The Seima installation guides refer to a remote access plate for that case.
Button placement matters most in an accessible bathroom. The Design for Dignity accessible toilets guide, published with the Australian Network on Disability, gives the flush control zone as 600 to 1100mm above the floor. A back-mounted control sits in a zone 500mm wide from the toilet centre toward the side away from the wall, and a side-mounted control in a zone 300mm either side of the toilet front. The guide points to AS 1428.1 for the full detail.
Before you order a Seima plate
Check four things. First, that the cistern is a Seima in-wall cistern, since the data sheets describe a system and the listings say the plate suits all Seima in-wall cisterns. Second, whether the cistern is pneumatic or mechanical, which decides between the 500 and the 500M. Third, where the plate will sit, front or top, and whether the wall is standard or nib. Fourth, the finish. Button options are sold separately, so a plate is bought on its own or alongside the cistern. If you are planning the whole toilet, see in wall concealed toilets.
If a pneumatic button feels stiff or does not flush
A Sydney Bathroomware guide to a pneumatic button from another maker describes a simple air test that shows how this type of plate works. You remove the plate, blow gently into the thin air tube, and watch whether the outlet bellows lift and trigger a flush. If they do, the mechanism works and only the button needs replacing. If nothing happens, the fault is likely in the pneumatic mechanism. The same guide says a half flush may fail to engage even when the button is pressed, and that a button can stick in its housing or snap off.
That guide covers a different product, so do not treat the steps as a Seima procedure. The useful part is the order: confirm whether the button is stuck, then check the tube and connections, and only then look at the mechanism. A Seima in-wall cistern is serviced through the flush plate, so a plumber can do this without opening the wall.
Keeping the plate clean
Seima's data sheets give one care instruction for the whole range: clean with a damp cloth, and do not use abrasive cleaners, liquids or pastes. Three of the finishes in the Flush Plate 500 sheet are PVD finishes. For brushed metal, the Buildmat help centre advises a soft damp cloth and mild dish soap, wiped with the grain, then rinsed and dried. It warns that water left on a brushed finish causes mineral deposits that get harder to remove the longer they sit, and that acidic cleaners, bleach, abrasives and vinegar should be avoided. That advice is for brass tapware, but the principle carries over to any brushed or PVD plate. Wipe splashes of bathroom cleaner off straight away, and keep spray cleaners away from the plate.
How Seima describes its approach
Seima's about page says the company applies a design and innovation ethos to everything it creates, draws on Australian design and culture, and works with architects and interior designers. It says it does not simply pick products off the shelf from overseas factories, and that its Australian designed products use the highest quality materials and meet the highest standards. Those are the company's statements about itself. The page does not say where each product is made, so this page does not state where the plate is manufactured. For a buyer, the practical gain of a system is that the cistern, frame, pan and plate come from one set of data sheets, which makes matching easier to settle.
Certification printed on the data sheets
Each Seima cistern data sheet carries a WELS licence number, a WaterMark licence number and a registration number for the cistern, and the cistern sheets state a 4 star rating at a 4.5 litre full flush and a 3 litre half flush. The MyHomeware guide to push button flush types says any flush component sold in Australia must carry WaterMark certification. It adds that cistern internals and connections to the water and waste pipes need a licensed plumber, who must provide a compliance certificate.
The plate is not the regulated part, but the cistern behind it is. Keep the data sheet and the installation guide with your plumbing records, and ask the plumber for the certificate when the work is done. Registration numbers differ between some Seima sheets and web pages, so quote the model name and order code when you ask a plumber or an inspector to check one.
Planning the opening before the wall is closed
The NSW Government plumbing advisory note 18/2022 says that cutting gyprock, or breaking fire rated, tiled and waterproof elements, in the future is not considered appropriate access to something that must be accessible. Its audits found such items inside walls that were waterproofed, tiled and fire rated with no provision for access, and it says the cost of fixing that falls on the owner or occupier. A Seima in-wall cistern is built to be serviced through the flush plate, which is why the plate is fixed in a way that lets it come off, and why the wall around it should be tiled to a clean opening. Before the tiler starts, confirm with the plumber whether the plate is front access, top access or remote, because each puts the opening in a different place.
Choosing among the finishes
The Flush Plate 500 sheet lists seven finishes, and the listings here show six of them: brushed nickel, gunmetal, brushed gold, white matte, black matte and chrome. Brushed nickel, brushed gold and brushed bronze are the PVD finishes on the sheet. Metal finishes make sense when the plate is meant to match tapware, a basin mixer or a towel rail. The sensible test is to hold a sample or a photo of the plate beside the other fittings in the room's own light. A nib wall changes the picture, because a plate set on top of the nib for top access is seen from above, in a different light from a plate on the front wall. Choose the finish with that position in mind.
Where to go next
A concealed cistern needs an in-wall setup, and in wall concealed toilets explains what that involves. Plates for other cisterns are on concealed toilet buttons, and the hinge covers and buttons made for the Seima Modia suite are on toilet hinge caps and buttons. The main toilets guide covers choosing a whole suite.
