Toilet flush buying guide
Arnold, Researcher / handyman, Birmingham10 guides
- Fill valve
Choosing the right flush for your cistern
In order to choose the right flush system, you will have to look at your cistern and take note of some measurements. Rest assured this process is fairly straightforward and shouldn't take more than five minutes!
- Measure the hole in the cistern lid (b) where the flush button will be installed (the diameter should range from 16 to 50 mm).
- Use your tape measure again to check the height of your cistern (d) (this should generally measure between 262 and 392 mm).
- While often standard in size, check the diameter of the outflow hole (b) of your cistern (this should measure 60 mm... in theory!).
- Although not strictly a measurement, you should also check where your fill valve is located (c) (either below or on the side of the cistern).
- Many systems are sold with floats. If your float still works well, there is no need to change it. In this case, you should ensure you only purchase the valve system.
- Fill valves have an adjustable base, allowing you to alter their height beneath the cistern lid.
- You can also choose between a single or double flush button – bearing in mind that dual flush models are less wasteful!
Toilet flush parts and assembly
The toilet flush is simply the system that allows wastewater to be removed from the toilet pan and be replaced by clean water.
Its basic operation centres around a certain amount of water being released from the cistern in one go. This volume of water creates a flow that carries away the waste and toilet paper.
The cistern, or toilet tank, is connected to a water supply hose at one end and the toilet bowl at the other. It also contains the toilet's key component: the flush mechanism, which is used to regulate the inflow and outflow of water in the system.
Different types of toilet flush mechanism
Nowadays, flush systems are installed directly above the toilet pan – gone are the days when cisterns would have to be installed two metres above the pan and operated by a pull chain!
The control used to operate the flush system is found at the top of the cistern. There are several different control types: lever handles, pull handles, single push buttons and dual push buttons.
Flush control: pull handles or push buttons
- Pull handles: These controls require you to pull up a metal rod to open the flush system and release water from the cistern into the toilet pan. This system is generally considered outdated as it does not allow you to control the amount of water released with each flush.
- Single push button: A much-improved option, this system allows for better control over how much water is released. It is sometimes even possible to stop the flow of water once the bowl has been cleared of waste, without having to wait for the cistern to empty completely.
- Dual push button: The most advanced control of all, this system consists of two buttons: one small and one large. Pressing the small button will release less water than using the large button. This will help you to save water – after all, there's no need flush away waste with twelve litres of water when six would do! Additionally, you can even adjust the volume of water released when using the smaller button.
Connecting the push button to the flush mechanism
The dual push button sends information to the rest of the mechanism through a control system. There are several different possibilities:
- Cable: the push button (or pull handle) is connected to the flush mechanism by means of a cable. The advantage of this system is that you can access the cistern without having to remove the button. This mechanism is also compatible with remote flushes (which can be installed to the side of the toilet lid).
- Mechanical control: the push button or pull handle is connected directly to the flush mechanism. This advantage of this system is that it tends to be more durable. It also allows you to easily adjust the amount of water released (when using push buttons). The biggest drawback of some pull models is that you have to remove all or part of the button to lift the cistern lid and their use is usually restricted to the hole found in the middle of the lid.
Different types of fill valves and toilet floats
Toilet fill valves
The cistern is linked to the water network of your home by a special valve.
This fill valve is connected either below or on the side of the cistern. It is also attached to a float and a flush valve designed to stop the cistern from filling once it contains a certain volume of water.
Side-entry fill valve
This type of fill valve is connected to the side of the cistern and tends to be quite noisy as water flows on the surface. Side-entry fill valves feature a screw that comes in a standard size (12x17) and these are generally made of chrome-plated brass.
Bottom-entry fill valve
Bottom-entry toilet fill valves send water into the cistern from below, meaning they make little or no noise when filling up. The fill valve is connected to a flow control device equipped with a float.
The float shuts off the valve when the water in the cistern reaches a maximum level.
Toilet fill systems are generally supplied as a fill valve and float in one single part. There are two main types of float:
- Float ball valve: the float shuts off the valve via a lever to stop the flow of water.
- Float cup valve: the float rises along an axis or track shutting off the valve to stop the flow of water.
Installing and maintaining your flush mechanism
Take care to clean your flush mechanism regularly – especially if you live in an area with hard water. Limescale can build up the joints of the mechanism and can affect the seal between the cistern and the toilet pan.
Arnold, Researcher / handyman, Birmingham 10 guides écrits
I'm a trained chemist working in the pharmaceutical industry as well as a self-taught DIY enthusiast. Oh, I'm also a new dad, but that doesn't stop me from tinkering because working with my hands is second nature to me. I'm motivated by the extra energy it gives me - and I love making things for my daughter.
The word 'tinkering' doesn't always describe what I do in my free time, though. I've already installed five kitchens, renovated a flat and built an extension for my own house. Over the last three years, I've pretty much done it all: insulation, plasterboard, electrical work, patching, painting, parquet, sanitation. That basically adds up to 60 m2 of work made entirely with my own two hands!
Lucky for me, my wife is passionate about decorating and interior design. It means I don't have to worry about things like colours and patterns.
My motto: great tools and materials are only half the battle, the rest is patience and attention to detail. So, if you need advice, look no further! We're here to help and we're passionate about what we do.
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