Bathtub overflow drain: operating principle, installation diagram and installation rules

The arrangement of a hygienic room hides many subtleties and nuances.We are talking not only about the purchase and installation of plumbing fixtures and fittings, but also about externally almost invisible, but important devices. One of these devices is a bathtub drain and overflow, the operating and installation features of which are worth familiarizing yourself with.

The article we have presented describes in detail the principle of operation of a drain with overflow, and examines the varieties used in everyday life. We will tell you everything about the selection criteria and the leading manufacturers in the segment. Our recommendations for care and operation will help you avoid problems and extend your service life.

Types and principle of operation of equipment

The overflow drain removes used liquid and prevents the bowl from overflowing due to uncontrolled water supply. The structure provides two holes - at the bottom and in the wall of the bathtub. They are supplied with interconnected hoses connected to the sewer drain.

Features of mechanical devices

There are three options for drain and overflow systems on sale. The difference between them lies in the method of removing the plug blocking the drain hole. If you are planning to buy a bathtub drain and overflow and are not sure which one is better to choose, you should pay attention to the model of your bathtub and its location in the room.

The simplest type of device is determined by the traditional design, found in almost every apartment. It has no moving components or levers. Water is drawn in when the plug is closed, and released when it is opened.

Mechanical products rarely break down and last a long time. The plug is attached to the drain grate on a chain, removed and placed in the opening manually

Products in this category differ in the type of connection to the sewer, sealing of connections, and the shape of the pipe. Devices include the following elements:

1. Drain neck. Installed in a hole made in the bottom. It consists of a chrome funnel that “catches” large particles of debris, and an expanding pipe with a built-in nut. The parts are joined with a reinforced metal screw. A rubber ring seal is responsible for the impermeability.
2. Overflow neck. Inserted into the wall of the bathtub. The design is similar to a drain, but is adjacent to the general contour of the network through a lateral, rather than direct, drainage system.
3. Siphon. An arched removable pipe designed to act as a water seal. Blocks attempts of unpleasant sewer odors to enter the bathroom. Connects mechanisms with each other and with the sewer network. Available in a variety of configurations. Models with a deep shutter that holds at least 300 ml of liquid are considered optimal.
4. Connecting corrugated tube. Diverts water entering the overflow to the siphon. Connects to other components with pipes.
5. Auxiliary pipe - soft or hard. Provides drainage from the siphon into the sewer pipe.

The kit also includes connecting parts that increase the tightness of the system.These are flat and conical gaskets used together with a union nut. Conical products are mounted from the nut with a sharp edge so that the thin part goes inside the opposite element.

Devices not equipped with mechanisms are produced in universal sizes and are designed for bathtubs with an average distance from the center of the overflow to the drain not exceeding 57.5 centimeters

Advantages of manual strapping: budget price, simplest assembly/installation algorithm, rare breakdowns, reliability. Among the disadvantages, rapid wear of the seals should be noted.

Characteristics of semi-automatic devices

A later modification of the traditional design is a semi-automatic system. It contains the largest number of components. It is supplemented by a control unit that raises/lowers the plug, a shutter valve, and a cable that controls its position.

The control unit is implemented in the form of a handle, valve, rotary ring, button. You can operate it by turning the lever 90 degrees or pressing a button without bending over to the bottom of the bathtub. Thus, the shut-off rod rises and falls, opening or closing the valve

The system is activated by tightening and releasing an auxiliary cable located inside or outside the overflow pipe. The first option looks more aesthetically pleasing, but is much more difficult to repair.

Advantages of semi-automatic machines:

• Convenience of closing the drain (without having to bend over or wet your hands);
• comfortable management and operation;
• stylish design.

The disadvantages of the device include a complex structure with a mass of moving and connecting components and the risk of the cable jamming over time.In semi-automatic systems, the overflow holes are hidden behind the control unit. Visible details perform a decorative function in the interior thanks to a thoughtful design.

What are the benefits of automatic drains and overflows?

A distinctive feature of automatic systems is their complex structure with a click-clack valve button, equipped with a latch and a built-in spring.

In automatic systems, the button, as in mechanical ones, is operated manually (or by pressing the heel of the foot while in the shower). When pressed, the plug lowers, closing the drain opening. If you repeat the manipulation again, it rises, starting the drainage of water

The buttons are designed in elegant high-tech, modern, and retro design styles. They are made from brass and copper, coated with chrome or nickel plating.

Advantages of automated devices:

• ergonomics and presentable appearance;
• compactness;
• convenient drainage.

There are also many disadvantages: the high cost of the proposals, the vulnerability of the spring holding the valve, difficulties in replacing the button, painstaking installation, often requiring professional intervention.

The automatic drain can be equipped with the functionality of collecting water. It is considered if it is impossible to rationally place a faucet in the bathroom.

The diagram includes pipes for the liner, which are connected to the overflow hole. The bowl is filled through the top connector, which eliminates flooding, since the flow automatically stops when there is an excess of water.

In addition to the usual types of fittings, there are separate products adapted to the characteristics of specific bathtub models

What are drain systems made of?

In the production of devices, materials are used that are resistant to corrosion, alkaline and acidic substances, and hot water. In the last century, when the range of plumbing equipment was quite narrow, drainage systems were made mainly of ferrous metal.

Although this material quickly loses its original aesthetics, it serves well for a long time, bravely withstanding high pressure and temperature changes. Despite its advantages, now manufacturers still give preference to non-ferrous metals and plastic.

Plastic harnesses are attractive at an affordable price. They are appropriate in bathtubs equipped decorative screen. Their universal dimensions adapt to non-standard sewer outlets and drains.

Plastic products are light in weight, easy to assemble, and do not undergo deformation due to the interaction of moisture and impurities contained in it

Metal objects are significantly ahead of plastic in terms of strength, service life and design. The most common products are made of brass, bronze, and copper. Chromium or nickel is applied to the drain grids and certain parts in them using electroplating techniques.

Provided that the devices are cleaned in a timely manner and the washer joints are disassembled, unlike plastic, they are unlikely to fail even after decades.

You can understand what kind of metal the structure is made of by carefully examining the pipe connecting the drain and overflow holes. Copper is recognizable by its reddish tint, ductility and softness. Brass is a durable yellow alloy of zinc and copper. Bronze is a fairly hard, dark brown material containing copper and tin.

Bronze and brass trims look great in classic and retro interiors. They look very elegant and neat, which is especially valuable when the bathtub is in the center of the room

Main selection criteria

When choosing a device, buyers are guided by personal requirements and wishes. It is no less important to evaluate the product you like taking into account other serious criteria.

For example:

1. Price category. For a low budget, plastic equipment with manual draining is optimal. A more expensive device with automatic/semi-automatic mechanisms is suitable for those who are looking for a solution with an original style and a convenient modern design.
2. Material. The quality indicator of propylene is a dense shell, brass is a perfectly smooth surface, cast iron is the absence of the slightest cracks, since they cannot be repaired.
3. Additional options. Siphons may have several inlets for connecting other consumers in addition to the bath. They may not be used by closing them with a nut. In the future, this thoughtful step will give you a chance to save money on branching drains under the sink, washing machine and dishwasher.
4. Diameter matching - at the siphon and sewer pipe. If the sections are incompatible, you need to select rubber or plastic adapters.
5. Completeness. The kit of any system must include all elements for connection, O-rings, gaskets for pipes and overflows to prevent leaks.

Another criterion that is far from least important is the manufacturer of the plumbing fixtures. The service life and proper operation of the selected drain-overflow system depend on it.

Rating of the best manufacturers

In order not to get into trouble and not suffer with a problematic product of dubious quality, you should purchase products from well-known and trusted European companies. They produce equipment according to generally accepted international standards and norms.

Geberit. A high-quality Swiss brand with a wide range of products at mid-range prices. The product is easy to use and adapts well to non-standard sizes.

Most designs have an adjustment plug near the overflow hole that opens the drain plug

Alcaplast. One of the largest manufacturers of sanitary ware in Eastern and Central Europe. The Czech brand produces devices with a special design and simple construction, which stably and silently perform their functional tasks throughout their entire service life, regardless of the influence of aggressive environmental factors.

Kaiser. Manufacturer from Germany, producing trims for modern bathtubs. The company's products allow you to adjust the length of the siphon over a wide range, which makes it possible to easily install it, including in deep bowl models.

Viega. A German company that has established itself in the market as a manufacturer of safe plumbing products of the highest quality that can last about half a century. They successfully combine design and engineering ideas.

The assortment includes drain-overflow systems with different shapes, materials, and color variations. They are characterized by a relatively low price and simple installation.

Many Viega models have a water filling function. They are convenient for rooms where there is not enough space to install a faucet.

Hansgrohe. Another representative of good German quality. The company's harnesses are reliable, efficient, and feature a complex, high-tech structure. In interiors they are valued for their functionality and excellent decorative performance.

Rules for installation work

Having experience installing a mechanical drain in a bathroom, you won’t need a circuit for a semi-automatic one - it is almost identical. Even without the skills, you can master it with your own hands, but first, it is advisable to read the instructions and documents that come with the kit.

Manufacturer's recommendations regarding installation of bath trim must be followed with precision. Otherwise, the device may not work or function incorrectly. It is not recommended to take on automatic systems: after installation without the participation of a specialist, the warranty on the device ceases to apply.

At the first stage, the old siphon, if any, is removed, and the insides of the pipe and the junction areas are thoroughly cleaned. Then the lower overflow is installed. A sealing collar is put on the outlet, after which it is placed against the drain opening.

Before installing the drain and overflow, it does not hurt to make sure that the bathtub is positioned correctly, stable and level and that the gap from the drain hole to the floor is at least 15 centimeters

Another gasket is placed on the inside of the hole, the lid with the grill is screwed on and secured with a screw. Cone-type cuffs are placed with the thick edge towards the nut, and the narrow edge towards the neck.

After checking that the connection is correct, tighten the screw with a screwdriver. The top overflow is installed using a similar method.

Tying under the bathtub is quite difficult.Most likely, you will have to take an awkward position to get to the right places. To fasten the inner and outer parts of the drain structure, it is advisable to work with a partner

The next stage is attaching the overflow to the drain. To do this, it is more convenient to use a flexible corrugated hose that stretches to a size that will easily fit into the pipe. Each joint is crimped with a nut and spacers.

Next, a glass for forming is installed water seal. Places for gaskets are first cleaned of defects with a file. The valve is also connected with a union nut with a flat or cone seal.

At the end, the siphon outlet is connected to the sewer with a drain pipe. This is done through the sealing collar or directly into the socket. To avoid leaks that occur due to cuff wear, they are treated with silicone lubricant.

When performing installation, do not use excessive physical force. Because of this, the strapping elements may burst, and you will have to buy new parts.

When the installation work is completed, you need to check the quality of the assembly by covering the drain with a stopper and opening the water. The floor under the bathroom is covered with paper, the drain and connections are inspected. When leaks are detected, the nuts are tightened.

Tips for care and use

All drain and overflow systems require appropriate care. This is the only way to preserve their original condition and performance, ensure durability and high efficiency. Devices must be inspected regularly to ensure there are no mechanical damage or leaks.

Also, we must not forget about additional events:

• to prevent the accumulation of deposits and scale, the siphon is washed every three months with hot water with the addition of citric acid or suitable chemical oxidizing agents;
• approximately every six months, thin rubber gaskets that have lost their elastic properties are replaced;
• The water seal, which collects various contaminants and debris, is periodically cleaned.

If chips and cracks are detected during a visual inspection, the siphon must be replaced. Such malfunctions provoke flooding of premises and cannot be repaired.

Will familiarize you with the intricacies of installing a conventional siphon on a bathtub next article, the contents of which we advise you to familiarize yourself with.

Conclusions and useful video on the topic

Operating principles of automatic systems in video:

In the video there is an overview of the semi-automatic drain and overflow:

A competent choice of drain-overflow system guarantees complete, comfortable and high-quality functioning of the bathtub. Its installation is not difficult to cope with, the main thing is to correctly assemble the parts and properly seal the junction areas. If strange problems still arise, it is always better to turn to professionals.

Would you like to share your experience gained during the installation of a drain and overflow system yourself? Do you have information that may be useful to site visitors? Please write comments in the block below, post photos related to the topic of the article, and ask questions.