How to repair or replace a Roca cistern mechanism

What you need

• 17 mm open-ended spanner or an adjustable spanner
• Flat-nose pliers
• Small flat screwdriver
• Sponge, cloth and bucket
• Old toothbrush
• Phone torch
• Roca dual-flush valve for your model (D1D or D2D depending on cistern, 20 to 35 euros) or universal Wirquin Jollyflush / Geberit Impuls
• Roca dual push button if the rods are broken (12 to 25 euros)
• Roca side-entry or bottom-entry fill valve, or universal Wirquin Jollyfill / Geberit Unifill (15 to 25 euros)
• Loose flush seal if you are only replacing the rubber (4 to 8 euros)
• Cleaning vinegar for the limescale
• 3/8 by 1/2 inch flexi hose if the current one is rusty

Step by step

1. 1

   Close the isolation valve and empty the tank

   Turn the isolation valve to the right as far as it goes, flush, and sponge the bottom dry. If the valve will not close, use the main stopcock for the flat.

2. 2

   Remove the Roca push button

   Hold the chrome collar of the button and turn it to the left until it comes free; on the Dama and Meridian press both buttons at the same time while turning. Lift out the button and look at the two rods: if one is broken or the spring does not return, buy the complete button.

3. 3

   Lift the lid and remove the flush valve

   Lift the lid off carefully (it is ceramic and heavy). Turn the body of the valve a quarter turn to the left and pull upwards: it is a bayonet fit on the base that stays fixed in the bottom. If it is stuck fast with limescale, work it gently in both directions.

4. 4

   Replace the seal or the whole valve

   Clean the seat on the base where the rubber sits with vinegar and the toothbrush. If the valve is less than 5 years old, fit the new seal in the groove without twisting it. If it is older or the plastic has yellowed, fit the complete new valve on the bayonet and adjust the telescopic height so the overflow sits 2 cm below the lid.

5. 5

   Replace or clean the fill valve

   Put the bucket under the inlet, unscrew the flexi hose with the 17 mm spanner and clean the mesh filter. If you are replacing the float valve, unscrew the outer nut, lift the old one out from inside and fit the new one with its washer inside the tank. Tighten the nut hand-tight plus a quarter turn, and connect the flexi hose without PTFE tape.

6. 6

   Set the water level and the button height

   Put the lid on without the button and screw the button in. The rods should just touch the top of the mechanism with 1 or 2 mm of clearance; use the adjustment screw on the body until you get it. Set the float so the water sits 2 cm below the overflow.

7. 7

   Turn the water on and test both flushes

   Open the isolation valve slowly, let it fill and try the small button and the large one. Check the button returns on its own and that there is no trickle of water in the bowl after 15 minutes. Check the flexi hose nut with a piece of dry paper.

Repairing the fill or flush mechanism of a Roca cistern: which part is at fault

A Roca cistern has three parts that are replaced separately: the push button (the two buttons and their rods), the flush valve (the central body with the rubber seal that closes the hole in the base) and the fill valve or float valve (where the flexi hose connects). Each fault points to one of the three.

If a Roca dual-flush cistern leaks water into the bowl, it is the flush valve seal, deformed by limescale, or the water level set above the overflow. If the button stays down or has to be pressed twice, the push button rods are broken or set at the wrong height. If it is slow to fill or will not fill, it is the filter or the diaphragm in the fill valve. If it does not shut off and overflows, the fill diaphragm is split or the float has water inside it.

One Roca detail: on the Dama, Meridian and The Gap the flush valve is shorter than on the Victoria, because the cistern is lower. So it is worth taking a photo of the open cistern when you go to buy the spare, or finding the model reference on the sticker inside the lid.

Genuine Roca or universal mechanism: which to buy

Roca sells every spare separately: the dual push button, the flush valve (listed in the spares catalogue as D1D or D2D depending on the cistern) and the side-entry or bottom-entry fill valve. You find them in any ferretería (hardware shop) with a plumbing section, at Leroy Merlin and Bricodepot, and in online Roca spares shops. They cost 30 or 40 per cent more than a universal, but they fit first time, the button sits flush with the lid and the cistern keeps its 3 and 6 litre flush.

A universal mechanism from Wirquin (Jollyflush, Tronic) or Geberit (Impuls) works in the Victoria and in most close-coupled cisterns: they are telescopic and come with their own button. The drawback is that the universal button sometimes sits higher than the Roca lid or the hole has to be enlarged. On compact cisterns (The Gap, Dama Senso, compact Meridian) and on models with a very thin lid, the genuine part saves headaches.

Common mistakes with the Roca push button and mechanism

The first is trying to lever the push button out with a screwdriver. The Roca chrome collar unscrews; if you force it, you break the plastic tabs and will have to buy the whole button. If it is stuck with limescale, wrap the collar in a cloth, turn it to the left by hand and, if it will not give, apply hot vinegar around it and wait 10 minutes.

The second is fitting the flush valve without adjusting the button height. The rods need 1 or 2 mm of clearance with the lid on. If they are tight, the valve does not close fully and the cistern leaks; if they are too long, the button bottoms out and will not flush. Almost every Roca mechanism has an adjustment screw or wheel at the top of the body.

The third is forgetting the rubber washer that goes under the fill valve, inside the tank. Without it, the cistern drips from the outer nut and the new part looks faulty. And the fourth, tightening that outer nut with a spanner: hand-tight plus a quarter turn is enough, the plastic cannot take more.

When to call a professional

Call us if the push button is broken and you cannot identify the cistern model, if the lid belongs to a discontinued model (many 1980s and 1990s Roca cisterns in Benidorm or Torrevieja), if the collar snapped while unscrewing the button, or if the isolation valve will not close and you cannot work with the water off. Also when the cistern is concealed in the wall: the Roca In-Wall mechanism comes out through the button opening and it takes practice.

The Manitas Costa plumber replaces a cistern mechanism for 60 to 110 euros, with the mechanism included in most cases. We carry Roca and universal spares in the van, so it is usually sorted on the first visit, in 30 to 45 minutes. Fixed price by WhatsApp from a photo of the open cistern, 6 months written guarantee and an invoice with IVA (VAT). More rates in how much a plumber charges in 2026.

Limescale on the coast: how to extend the life of the mechanism

The hard water in Alicante and Valencia is the reason a Roca mechanism lasts 5 or 8 years here instead of 15. Limescale builds up in three places: the flush seal, the fill filter and the button rods, which stick. Once a year, with the lid off, wipe cleaning vinegar over the seal and the seat, clean the filter on the flexi hose and work the button several times with the rods dampened.

Never drop chlorine tablets into the tank: Roca advises against it because they degrade the seal and the diaphragm. If you have a second home, close the isolation valve when you leave. And if the problem is that the cistern leaks or will not fill but you do not yet know where, start with the guides toilet cistern keeps running and toilet cistern not filling, and if what you want is to replace the whole tank, how to replace an old toilet cistern.