A wall-hung commode leaves the floor beneath it clear, but the frame and flushing system sit behind the finished wall. Those hidden parts need to be chosen before the tiling starts. The GROHE Rapid SL concealed tank combines a steel support frame with a cistern for this type of installation.
If you are comparing a GROHE full frame concealed tank for a bathroom in Lahore or elsewhere in Pakistan, check the article number, the commode’s fixing measurements and the fittings included in the box. A photograph of the flush plate alone will not tell you whether you are looking at a complete set. You can also compare our wider range of concealed tanks for wall-hung commodes.
Factory-set reduced and full flush
WC fixing centres, about 7 / 9 inch
Air-operated dual-flush plate
Frame and cistern, flush plate, brackets
What the GROHE full frame does
The Rapid SL frame supports the wall-hung commode and holds the cistern and pipe connections in position. It is fixed to the building as specified in the installation instructions before the wall is closed. The tiles and wall finish should never be treated as the structural support for the commode.
GROHE lists fixing centres of 180 mm or 230 mm for the documented Rapid SL version. These are roughly 7 and 9 inches, which are familiar measurements in local sanitary shops.
Measure from the centre of one fixing hole to the centre of the other. Matching that distance is one compatibility check; the waste connection and the commode’s flushing requirements also matter.
Understanding the two flush buttons
The documented GD2 cistern is factory set to a 3-litre reduced flush and a 6-litre full flush. The reduced flush uses less water when a full flush is unnecessary. Your installer should confirm the final settings against the selected commode and the instructions for the actual cistern.
Seen “6–9 litres” in a catalogue? That is not an instruction to describe the smaller button as a 6-litre flush and the larger button as a 9-litre flush. Check the factory settings and any permitted adjustment for the particular model.
How the pneumatic flush works
Pressing the flush plate sends an air-pressure signal through a small pneumatic hose to the discharge valve. The valve then releases water from the cistern into the commode. The air hose operates the valve; it does not carry the flushing water.
If a button stops responding, the hose connection and the valve mechanism need checking. Replacing the visible plate without inspecting the system may leave the fault unresolved.
What comes with GROHE Rapid SL 38772001
The manufacturer lists article 38772001 as a 3-in-1 set with the Rapid SL WC element, a chrome Skate Cosmopolitan flush plate and front wall brackets. The cistern is part of the WC element. Ask the seller to identify the set by its article number and show the contents of the sealed box. See the GROHE Rapid SL 38772001 concealed tank page for the set and a price enquiry.
The complete installation also uses a filling valve, discharge valve, inlet and outlet connections, seals and WC fixings. Local names include filling cock, syphon, connection pipe and thimble. A set photograph is useful, but a parts list is a better way to confirm what is supplied. The wall-hung commode and seat should be quoted separately unless they are expressly included in a bathroom package.
GROHE Rapid SL 38772001 at a glance
Reference article
38772001 – Rapid SL 3-in-1 WC set
Installation height
1.13 m for the documented set; check the drawing
Frame / WC element
Rapid SL 38528001
Cistern
GD2; published 6–9 litre specification
Factory flush settings
3-litre reduced flush / 6-litre full flush
WC fixing centres
180 / 230 mm, approximately 7 / 9 inches
Flush plate
Skate Cosmopolitan chrome 38732000
Wall brackets
3855800M in the documented 3-in-1 set
Water supply
1/2-inch connection with integrated angle valve
Documented reference values for model 38772001. Confirm the article number, set contents and instructions of the unit you buy.
Check the commode before closing the wall
Choose the frame and commode together. A matching bolt distance alone does not establish that every part will fit. Before the wall is closed, check:
- Fixing centres: 180 mm or 230 mm
- Inlet and waste connections
- Flushing volume the commode needs
- Space available behind the finished wall
- Commode height from the finished floor level, including tile thickness
- Frame secured, pipework checked and leak-tested before tiling
- Inspection opening kept accessible for the valves
Set the commode height with the finished floor level in mind. The installer should secure the frame, check the pipework and test for leaks before cladding and tiling, so the serviceable valves can still be reached later.
Filling cock problems and routine servicing
The filling valve, often called the filling cock or float valve, controls water entering the cistern. Dirt or deposits can interfere with its operation. Slow refilling or water that continues to enter the tank should be investigated rather than left to waste water.
Water running into the commode can also come from a discharge valve seal or an incorrect water-level setting. It is not always a filling cock fault. A technician should identify the cause before deciding whether a component needs cleaning or replacement.
Routine valve servicing is normally carried out through the opening behind the flush plate. Damaged hidden pipework or other structural faults may need additional access.
Before servicing: isolate the water and follow the manufacturer’s method for releasing clips and removing parts. Use a cleaning method suitable for the valve and its seals; harsh chemicals can cause damage instead of solving the problem.
The visible flush plate
The Skate Cosmopolitan chrome plate supplied with the documented 38772001 set has separate controls for reduced and full flushing. It is the part you see after the installation is finished, so its shape and finish are worth comparing with the other fittings in your bathroom.
Keep the chrome surface clean using the manufacturer’s care instructions. Avoid abrasive pads, and do not buy a replacement plate solely because its outside dimensions look similar. The actuation system and mounting arrangement must match.
Original GROHE spare parts and warranty
Keep the invoice and the product article number. They make it easier to identify a replacement valve, seal, hose or flush plate when service is needed. Spare parts should be matched to the installed cistern version, as similar-looking GROHE components are not automatically interchangeable.
Before purchasing, ask for the warranty terms that apply to the unit sold in Pakistan. Confirm the duration, exclusions and claim process in writing. A general five-year warranty statement does not establish coverage for every component or promise a company visit to every site. Check the country-of-origin label on the supplied box rather than relying on a generic description.
GROHE concealed tank spare parts: photo guide
Local names for concealed tank parts vary from shop to shop. Use these GROHE reference photos to describe the part you need, then send us a photo of your installed part so we can match the exact version.
Syphon (discharge valve) – AV1 42320000
AV1 discharge valve reference, often called a syphon locally. It releases water from the cistern when you press the flush plate.
Syphon pipe (flush pipe) – 43908000
GROHE concealed flush pipe 43908000. Confirm with your installer which piece is meant by “syphon pipe” before ordering.
Thimble (flush pipe connector) – 37119000
GROHE 55 mm rubber flush pipe connector, the piece often called a thimble locally. Match it to your commode inlet.
WC fixing bolts – 4276400M
Threaded bolt pair that holds the commode to the frame. The photo does not show every item in a complete bolt kit.
GROHE concealed tank price in Pakistan
When asking for a price, specify whether you need a frame and cistern, the complete 3-in-1 set, or a package with a wall-hung commode and seat. A lower quotation may cover fewer items. Ask for the article number, included fittings and installation charges to be listed so you can compare quotations properly.
For the current GROHE Rapid SL concealed tank price and availability, contact Design Bath with the model number or a photograph. Our team can help with product selection, original spare-part enquiries and service enquiries. If you need help with an existing tank, send a picture of the installed unit and describe the fault.
Visit Design Bath on Main Walton Road, near Defence Mor, Super Town, Lahore, to see our GROHE bathroom fittings, or call / WhatsApp 0324 6669988 to discuss a concealed tank and the fittings needed for your bathroom.
DESIGN BATH · LAHORE
Main Walton Road, near Defence Mor, Super Town, Lahore · Call or WhatsApp 0324 6669988
GROHE concealed tanks and flush plates at Design Bath
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Planning the rest of the bathroom? Browse all GROHE bathroom fittings or read our guide on how to choose GROHE bathroom fittings in Pakistan.
Frequently asked questions
What is a GROHE Rapid SL full frame concealed tank?
It is a concealed WC installation system with a steel frame and a cistern. The frame supports a compatible wall-hung commode, while the cistern and most connections sit behind the finished wall. The flush plate remains visible.
Is a 7-inch or 9-inch wall-hung commode compatible?
The documented Rapid SL version has 180 mm and 230 mm fixing centres, approximately 7 and 9 inches. Check the commode’s inlet, waste connection and flush requirements as well. Bolt spacing alone does not confirm complete compatibility.
Does the smaller button use 6 litres and the larger one 9 litres?
The documented GD2 factory settings are 3 litres for a reduced flush and 6 litres for a full flush. A 6–9 litre cistern specification does not mean the two buttons are automatically set to 6 and 9 litres.
How does the pneumatic flush plate operate?
Pressing a button sends air pressure through a small hose to the discharge valve. The valve releases water into the commode. If the button does not respond, the hose connections and valve should be checked.
What is included in model 38772001?
The manufacturer lists a Rapid SL WC element with cistern, a chrome Skate Cosmopolitan flush plate and front wall brackets. Confirm the local box contents before buying. The commode and seat are separate unless the quotation specifically includes them.
Can the concealed tank be serviced without removing the tiles?
Routine work on the accessible filling and discharge valves is normally carried out through the opening behind the flush plate. A damaged concealed pipe, frame or other inaccessible fault may require additional work. Keep the service opening accessible.
Why does water keep running into the commode?
Possible causes include debris in a valve, a worn discharge seal or an incorrect water-level setting. A filling valve fault is one possibility, but it should not be assumed. Have the system checked before replacing parts.
Are GROHE concealed tank spare parts available?
GROHE publishes spare-part information for its cisterns. Ask Design Bath about the current availability of the part matched to your installed model. Send the article number and a clear photograph; availability can vary by component and cistern version.
What is the GROHE concealed tank price in Pakistan?
Request a current quotation for the exact article number and package. Check whether the price covers the flush plate, brackets, commode, seat and installation. Contact Design Bath Lahore on 0324 6669988 for a model-specific enquiry.
Does every GROHE concealed tank have a five-year warranty?
Confirm the written warranty supplied for the unit sold in Pakistan. Duration, component coverage, exclusions and service arrangements can differ. Keep the invoice and ask how a claim is handled before the tank is installed.
Can Design Bath help with a filling cock or flush valve problem?
Yes. Contact Design Bath with the model number, a photograph and a description of the issue. Ask about the suitable replacement part, service options and any visit charges before arranging work. Water should be isolated before a technician services the tank.
ABOUT THIS GUIDE
Written by the Design Bath product team in Lahore. Technical answers follow GROHE’s documented reference model 38772001; the installation instructions supplied with your unit take precedence. Product photographs are manufacturer and retailer reference images.
Last updated: 10 October 2026