How to Replace Flush Valve in Concealed Cistern

How to Replace Flush Valve in Concealed Cistern

If you are experiencing problems with your toilet cistern not flushing properly or even continuously running, the issue may be with the flush valve. The flush valve is responsible for controlling the amount of water that enters the toilet bowl when you flush. Over time, flush valves can become worn out, stuck or damaged and need to be replaced. In a concealed cistern, you may be wondering how to replace the flush valve as you cannot see the parts easily. However, with the right tools and a little bit of know-how, replacing a flush valve in a concealed cistern is relatively straightforward.

Step 1: Turn off the Water Supply

The first step in any plumbing job is to turn off the water supply. This will prevent water from continuing to pour into the cistern whilst you are making repairs. Locate the isolating valve on the water supply pipe and turn it clockwise until it is fully closed. This should stop water from flowing into the cistern.

Step 2: Remove the Cistern Lid

Before you can access the flush valve, you will need to remove the cistern lid. This is a delicate operation, so be sure to handle the lid with care as they can be quite heavy and fragile. Locate the lid fixing bolts which are usually located at the top of the cistern and undo them. You may need to use a screwdriver or pliers to do so. Carefully lift the lid off and place it to one side.

Step 3: Empty the Cistern

Depending on the issues with your flush valve, you may need to empty the cistern before you can proceed with repairs. To do this, you can flush the toilet a few times until the water level has completely drained. You can also transfer the water from the cistern into a bucket or container using a cup or ladle.

Step 4: Disconnect the Old Flush Valve

On the underside of the cistern, you should be able to see the flush valve. This usually consists of a rubber seal, a threaded plastic nut and a plastic or metal arm that connects to the flush button or lever. To remove the old flush valve, start by turning the plastic nut anti-clockwise using a wrench or pliers until it is loose. Then, gently pull up the flush valve and remove it from the cistern. Be aware that there may still be water in the cistern at this stage, so you may wish to place towels or a container underneath to catch any spills.

Step 5: Install the New Flush Valve

Once the old flush valve has been removed, you can install the new flush valve by reversing the steps above. Start by placing the rubber seal onto the flush valve and insert it into the cistern hole. From underneath the cistern, screw the plastic nut onto the threaded valve and tighten it using pliers or a wrench. Be careful not to over-tighten as this can cause damage. Finally, connect the plastic or metal arm to the flush button or lever.

Step 6: Turn the Water Supply Back On

Now that the new flush valve has been installed, it’s time to turn the water supply back on. Slowly turn the isolating valve anticlockwise until it is fully open. This will allow water to flow into the cistern and refill it. Once the cistern is full, flush the toilet and check that the new flush valve is working properly.

Step 7: Replace the Cistern Lid

Once you are happy that the new flush valve is working effectively, it’s time to replace the cistern lid. Carefully put the lid back onto the cistern and reattach the lid fixing bolts. Tighten them using a screwdriver or pliers, but be sure not to overtighten as this can cause damage to the lid.

In conclusion, replacing a flush valve in a concealed cistern can seem daunting, but with the right tools and a clear guide, it can be done. By following the steps above, you can replace a faulty flush valve and get your toilet back to working effectively. If you are unsure about any aspects of this process, it’s always best to contact a professional plumber.