Sink trap - types and functions

A sink trap is a small yet important element of every plumbing system. If not for it, a bathroom or kitchen would be quite difficult and unpleasant to use. How to choose the right drain trap that will work well with the installations in your house or apartment? You can learn this from the article below.

Table of contents

  1. Sink trap - how does it work?
  2. Classification of traps
  3. Materials used in drain traps
  4. Sink trap installation and maintenance



Sink trap - how does it work?

Trap is a device that allows water to flow from a reservoir directly to the plumbing system. In plumbing installation, this element is a barrier that prevents sewer gases from getting into the bathroom. This way the room is protected from unpleasant smells that could flow from the sewer system or from wastewater tank. Sometimes the amount of water in a trap is not sufficient. Such situation usually occurs when the installation has not been used for quite a long time, which causes the water in pipes to evaporate. Removing the smell in that case involves filling the trap with water again.

Classification of traps

There are different types of traps available. To pick the right device that fits your appliance, it is good to know that traps are differentiated by various features: construction, material, purpose and appearance. See the most popular trap models used in water installations below.

Bottle trap is definitely one of the most popular and universal model. Its main advantage is small size, which allows to install the element directly under a sink or washbasin. For this reason it is perfect to use in small bathrooms and kitchens. A drain of this type is built vertically. Its lower part consists of an element that resembles a bottle - that is where water accumulates. It prevents unpleasant smells from escaping the piping system. Another important advantage of this type of trap is easy cleaning. To remove the dirt from inside of the device, just unscrew the lower part of the trap.

P-trap - it is a good alternative if you have more space to use. The typical shapes are U and S. This type of traps are horizontal. They rarely malfunction and are easy to clean. It is often said that this type of traps is self cleaning. Why? The trap gets cleaned every time it is used, when the water flows through. It is also resistant to incrustation - a process which can build up an obstruction, disrupting the proper water flow. They are quite easy to install - the manufacturers usually provide a detailed instruction.

Free float trap - it is used in spots that are prone to water backflow. It is equipped with a special ball, usually made of rubber. In case of a backflow, it is pressed into the outlet and the wastewater cannot escape outside.

Bathtub and shower traps - they differ from the other types, especially in construction and method of cleaning. They are quite flat, which results from the place of their installation. In both cases they are cleaned from the top, which is due to the construction of showers and bathtubs. The access to such drains is much more difficult than in sinks or washbasins.



Non-standard traps - with atypical construction, quite different than in the products mentioned above. They are designed for instance for disabled people (e.g. in sinks). This type of product allows to move a wheelchair close to the sink, which increases the comfort of using the appliance.

Concealed trap - installed in special constructions, used typically in showers and toilets. The whole installation is hidden in a wall. It is a perfect solution for anybody that values highly aesthetic designs.

Materials used in drain traps

Traps might be made of PCV plastic or copper. Products from the first group are quite durable: they are resistant to mechanical damage, corrosion and chemicals. They are usually white. Traps made of copper are very resistant, they are also good looking. Because of the chrome finish, they can be placed in visible spots.

Important Choosing the right trap for your appliance might be a difficult task. To make the right decision, you should consider all issues concerning proper functioning of the system. It will help you to choose the right product for your device.

Sink trap installation and maintenance

Drain trap is not a very complicated device and it’s relatively easy to install. If you need to replace an old water trap, you need to remove it first. To do it, just unscrew both ends of the trap bend (either by hand or with pliers). Carefully pour the water into a bucket. Then unscrew the arm.

Before installing a new trap, make sure that it will fit with the length. If needed, shorten one of the elements using a pipe cutter. Place all the nuts and washers at the ends of the elements. Put the arm into the wall drain and the bend into the sink drain. If all pieces are properly aligned, tighten the slip nuts. Check the fittings for any leaks by letting the water flow through. Tighten the nuts if it’s needed.

What is a trap?

Trap, or drain trap lets the water flow from a reservoir into the plumbing system. Its main purpose is creating a barrier that prevents spreading unpleasant smells from the installation.

How to install a bathroom sink drain p-trap?

Sink traps are not very difficult to install - just follow the instruction provided by the manufacturer. Installation usually involved sliding the parts into the sink drain and securing them with seals.

How to remove sink trap?

To remove a sink trap, unscrew the trap bend and carefully pour out its contents into a bucket. Then just unscrew the arm.

How to clean sink trap?

Disassemble the lower part of the trap. Pour out the contents and wash the pipe with clean water. Then put the element back into its place.

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