Connection of metal-plastic pipes. Compression fittings Connecting metal pipes with compression fittings

When connecting and repairing metal pipes, as a rule, threaded joints or welding are used. But in some cases it is not possible to cut a new thread, and welding work is extremely difficult to carry out due to the increased fire hazard or the inaccessibility of the junction of different sections of the highway.

In addition, these works require significant financial and time costs, and in this case, methods of connecting pipes without welding and threading are used, which make it possible to ensure a reliable and durable result without large investments and as soon as possible. We will briefly talk about these methods.

Metal pipes have a certain service life, and they are especially susceptible to corrosion in the area of threaded connections when high temperature liquids. Sometimes, due to the poor quality of the material, fistulas appear in the body of the pipes, which require urgent repairs, and in cast iron sewer pipes, cracks and chips can occur from mechanical stress.

Force majeure circumstances require a quick response to ensure reliable repair of gas, water, heating and sewer pipes without threading or welding. The industry has experience in connecting gas and oil pipelines in such a way that it ensures not only a tight connection, but also the absence of corrosion at the joint parts.

The need for prompt and high-quality repairs, as well as the implementation of a tie-in with a diversion from the main, pushed engineers to a number of design solutions. The basic principle of each of them is the connection of pipes without welding, ensuring a tight and durable connection of joints, even with high pressure and hot media in the system.

This process is carried out using the following most popular devices:

repair work using a clamp, this method can eliminate faults in the water supply and sewerage systems and even repair a car pipe;
flange connection with bolts using rubber gaskets;
repair and installation clips for water supply systems;
Gebo coupling or compression fitting, which allows you to connect sections and make bends from the main pipe, where the temperature of the carrier is not higher than 80 o C with the possibility reuse;
installation of pipes, rotating elements and branches using press fittings, which compress pipes using press jaws and provide high strength and tightness of the permanent connection.
main connections based on hermetic heat-shrinkable couplings using special equipment.

It is important when choosing to pay attention to intended use product, since it can serve either as a temporary repair device or be of a permanent operational nature, and its cost depends on this.

Unlike welded pipes, joints based on seals do not require special cutting of the ends, but only need to be cleaned of dirt, irregularities, rust and metal burrs in order to ensure the tightness of the joint.

Joining pipes using clamps, flanges and clips

The simplest devices for quick repair and joining of pipes are usually bolted and consist of two parts, which are put on the pipe and fixed in the right place using a rubber seal. An exception is the flange connection of gas pipes, which is bolted together through a rubber gasket in order to replace a section of the line.

Replacing metal and plastic sewer drains during repairs is also based on replacing damaged areas with the installation of rubber seals without tightening because there is no pressure in them. The main thing here is to prevent leaks, water flowing down by gravity and the appearance of odors.

A quick tap-in or repair using clamps and clips is not absolutely reliable, especially in systems with high pressure and temperature of the medium, and is a temporary measure. Clamps of various designs are one-piece or detachable pipe-like structures and are tightened through gaskets at breakout points using bolts.

They are designed to accommodate all pipe diameters up to 1520 mm and are available in single, double or triple. They are distinguished by quick installation on the damaged area, but require careful and consistent tightening of the bolts without distortions and deformation of the seals.

Connection using repair clips is more reliable because they are a cast body made of painted metal, consisting of two detachable parts. This method also uses a thick-walled rubber gasket, and both parts are connected with bolts.

Installation of clamps and clips is carried out in the following sequence:

the emergency area must be thoroughly cleaned of metal shavings, irregularities, rust and other contaminants;
if a clamp is applied, a rubber pad is wound around the damaged area and sealed;
if a repair clip is installed, then a rubber seal is put on, the cut of which is lubricated with a silicone sealing compound;
then the bolts are tightened sequentially and without distortion, in the case of a crosswise holder.

Repair clips allow for cross-shaped or T-shaped insertion, and are also used when connecting two sections of the pipeline.

During installation, it is important to avoid distortion of the seal, not to overtighten the bolts, and after supplying fluid under pressure, re-check the effectiveness of the repair and the tightness of the connection.

Connecting metal pipes using press fittings and couplings

The system of press fittings allows for strong, tight and durable connections of pipelines for various purposes, including heating ones, and is designed for high pressure and media temperature. The range also includes tees and swivel elbows with an angle of 45° and 90°, and if you have freezing equipment, you can quickly and efficiently connect new radiators directly during the heating season. A significant disadvantage of this system is the high cost of the equipment because this method requires the use of a special tool for crimping the fitting or press pliers.

A simpler solution to the problem of joining steel, cast iron and plastic pipes is the use of detachable couplings UR-01 with a double-sided bolted seal. These products serve For connections of pipes with a diameter of 50 to 300 mm and hold pressure up to 16 atm. The couplings are equipped with polyoxymethylene expansion rings with bicromet type clamps, and the body and pressure covers are made of high-strength painted cast iron. The O-rings are made of ethylene-propylene rubber, and the entire design allows for compensation of minor angular deviations, resists hydraulic shock and protects against tensile loads.

Inexpensive detachable solutions also include the Gebo compression coupling, which is available in single-sided and double-sided versions and allows you to make inserts and corner connections. It consists of the following main parts:

main one- or two-sided durable housing;
sealing conical rubber ring;
metal clamping ring;
a split clamping ring with a notch for fixing on the surface of the pipe;
a threaded nut that provides clamping, an airtight seal and fixation of the entire structure.

When assembling, it is very important to follow the assembly sequence of the Gebo coupling and the correct installation of the cone parts according to the factory instructions.

In the double-sided version, the coupling has compression rings on both sides and is used for threadless connection of two parts. The assembly process is extremely simple, but requires effective cleaning of the installation area from rust, contamination and metal shavings. Reliable fixation in terms of strength and durability is no worse than threaded connections and is ensured both by the friction of the sealing gasket and by fixation on the pipe body using a crimp ring. One of the advantages of this design is the possibility of reusing this element by replacing the rubber ring with a new product.

What do we end up with?

The methods we have considered for connecting pipes without welding or threading are a quick way to eliminate a break in the hot and cold water supply and sewerage system. The correct formulation of the problem and the right choice of product will provide you with troubleshooting and significant cost savings in an unforeseen situation that can happen in every home.

Compression fittings are very popular as they can be used to connect pipes made from the most various materials: polyethylene, metal-plastic, copper, steel, polypropylene.

Advantages of using compression fittings when assembling pipelines:

no soldering is required when connecting polyethylene pipes;
allow the pipeline to be disassembled if necessary. For example, when carrying out repair work to replace a section of a pipe or to clean a pipeline if it is contaminated;
ensure the tightness of the system;
this type of connection is resistant to vibrations and accidental mechanical impacts on the pipeline;
can be used in places of high humidity;
quite suitable for installing a pipeline intended for transporting drinking water;
a wide range of different configurations (couplings, bends, tees, adapters) and diameters (from 16 mm to 110 mm).

Features of the use of compression fittings

Compression brass fittings for HDPE pipes are usually used for installation of external pipelines. The use of compression fittings prevents the possibility of slipping of the ends of the pipeline under tensile forces, under the influence of pressure and temperature of the transported substances.
Compression fittings for metal-plastic pipes are made of nickel-plated brass. It is recommended to check the tightness of the connection with a compression fitting of metal-plastic pipes several times a year and possibly tighten them additionally.
Compression fittings for copper pipes are used when it is not possible to use open fire. Such fittings are made from metal-plastic, steel, copper and brass.

Compression brass fittings for copper pipes are in greater demand than copper or steel ones, since brass products are much cheaper and more malleable when processed. To increase the strength characteristics, brass products are additionally coated with nickel.

Compression fittings for polypropylene pipes are made of polypropylene. If it is necessary to connect polypropylene pipes with pipes made of another material, fittings with a plastic body and internal metal threads are used.
Compression fittings for steel pipes are an alternative to welding pipe joints. But since compression fittings are significantly inferior to welding in terms of the strength of the connection, designed for a long-term long-term result (when using compression fittings when assembling heating systems, under the constant influence of the high operating temperature of the transported liquid, the sealing ring of the fitting may lose its original performance properties, and the connection will depressurize) , it is recommended to use compression fittings as a temporary measure.
Compression fittings for connection are used in the assembly of external pipelines operating under high pressure.
A compression fitting for connecting a metal pipe is used when carrying out repair work on a pipeline. The compression fitting will act as an adapter. It makes no sense to connect metal pipes using compression fittings - it is better to use welding.

Installation of compression fittings

Compression fittings consist of a body, a split ring and a union nut. The use of compression fittings to connect pipes does not require the use of any special equipment. All you need is pipe cutters and a wrench. When tightening the nut with a wrench, the split ring on the pipe is compressed, which leads to a strong and tight connection between the walls of the pipe and the fitting.

The connection of polyethylene pipes with compression fittings is carried out similarly to the connection of metal-plastic pipes. But for polyethylene pipes, due to the softness of the material used for the manufacture of pipes, the use of compression fittings with a split ring is not acceptable, since when compressed, the walls of the polyethylene pipe may well be deformed. In this case, the compression fitting consists of a body, a union nut and a rubber seal instead of a split ring.

Cost of compression fittings

The price of compression brass fittings, depending on the diameter of the product and the manufacturer, ranges from 46 rubles. up to 470 rub. (domestic manufacturer); from 250 rub./pcs. up to 2700 rub./pcs. (foreign manufacturer);

The price of compression plastic fittings, depending on the diameter of the product, as well as whether the product is monopolypropylene or combined, with metal inserts, ranges from 20 rubles/piece. up to 1600 rub./pcs.

Video

Watch the video for instructions on connecting HDPE pipes with brass fittings:

When conducting installation work When assembling the pipeline, it is recommended to use high quality fittings made of a material similar to the material from which the pipes are made, and also taking into account functional purpose of the installed pipeline.

To save money when installing pipelines, the connection of metal-plastic pipes must be made in accordance with mandatory rules. Despite the fact that the price of components for this type of pipe is significantly higher than for polypropylene analogues, metal and plastic pipes today continue to be widely used in the construction of water pipelines and.

Metal-plastic pipes combine the advantages of two materials:

the metal in the composition of such a product provides it with strength;
plastic provides flexibility to the product.

Since metal-plastic pipes can be connected in various ways, you need to understand the features of each, and our article will help with this.

Connecting metal-plastic pipes to each other

Connection using compression parts

Basic rules (the work is not difficult, so you can do it yourself):

With this connection method, it is assumed to use special crimp fittings (connectors for metal-plastic pipes) made of brass. The part, which in this case is used to connect pipes, is a prefabricated structure - a union nut, a fitting and a split ring.
A wrench is required to get the job done.
The compression fitting can be disassembled if necessary and then reused.

Operating procedure:

prepare a pipe of the required length;
align the workpiece section at a distance of 10 cm before and after the cut line,
cut the pipe according to the markings using precision scissors, which are positioned at right angles to the axis of the pipe;
check the integrity of parts and gaskets;
put on the nut and then the fitting ring;
process the end of the pipe with a reamer - the internal chamfer is removed with the calibration side, and the external chamfer - with the other side;
use fittings for connection (the pipe must be pushed onto the fitting until it stops);
screw the union nut onto the fitting by hand and then with a wrench so that 1-1.5 turns of thread remain free.

When tightening the nut, you must be very careful so that the ring does not burst.

Connection using special press fittings

There are ways to connect metal-plastic pipes that allow for high-quality installation of a heated floor system, as well as hidden communications. One of them is to ensure the connection of metal-plastic pipes using press fittings. This connection is more reliable compared to the option when compression parts are used. To perform the work you will need a special tool -.

To know how to correctly connect metal-plastic pipes, you need to clearly understand the entire process of making the connection:

it is necessary to calibrate the cut edge of the pipe - remove the outer and inner chamfers;
check the pipe diameter with a calibrator;

check the presence of O-rings in the fitting, as well as the presence of a dielectric gasket;
place a crimp coupling on the edge of the pipe;
put o-rings on the fitting and insert it into the pipe;

crimp the steel coupling using press pliers (this tool should include liners for pipes of different diameters). When crimping a steel coupling, you must ensure that the side of the sleeve is in the recess of the press nozzle.

When making a press connection of metal-plastic pipes, it is not advisable to press the steel coupling twice.

If the press fitting has a coupling attached to it, then it is immediately placed on the pipe, and through the hole in the coupling, control the depth of its seating.

Connection using push-on fittings

With this method of connecting pipes, you will need, in addition to press pliers, an expander to expand the diameter of the pipe. The result is a permanent connection. It can be used for hidden installation of pipelines, including when pouring concrete.

When carrying out work it is necessary:

cut the pipe;
place a coupling on the edge of the pipe;
expand the edge of the pipe using an expander;
place the fitting on the edge of the pipe;
press the coupling;
the fitting is tightened onto the fitting, ensuring a reliable tight connection.

Application of a hybrid connection of metal and metal-plastic pipes

How are metal-plastic pipes connected to a metal riser? In this case, a hybrid connection is used.

For this job you will need a gauge as well as a compression fitting. If the products have different diameters, you should select a thread that matches the diameter of the metal pipe, and the washer with nut, collar and cone must match the metal-plastic pipe.

The work is carried out in this order:

you need to wrap tow on a metal pipe;
screw the fitting onto it;
Place a washer and nut on the metal-plastic pipe;
calibrate the edge of the pipe, put it on a cone screwed to a metal pipe;
Using an open-end wrench, carefully tighten the nut (the washer tightly squeezes the metal-plastic pipe).

You can and should make high-quality connections of metal-plastic pipes yourself. However, all work should be carried out in such a way that the connection technology is carried out accurately. In this case, special attention will need to be paid to and.

Most specialists and professionals in the field of repair and construction work in Lately It is increasingly recommended to use metal-plastic pipes when repairing and replacing plumbing pipelines.

Such pipes are quite practical and have a minimal number of disadvantages. They are quite affordable in price, have a long service life (50 years), are easy and unpretentious in transportation and installation.

And, nevertheless, you should know a few points about how to properly connect metal-plastic pipes in various variations.

Proper connection of metal-plastic pipes cannot be done without the help of appropriate tools. And any competent repairman, plumbing specialist or ordinary owner of a house or apartment knows about this.

If you suddenly need to independently install plastic pipes at home, connecting them in various ways and elements, then you will need the following tools and equipment:

ring wrenches (usually they are used in twos);
sliding key;
pipe bender (usually a simple pipe bender is used);

Pipe cutter

To cut pipes into various sections, separate pieces of pipe from a coil, or other methods of cutting metal-plastic pipes, you can use a special tool - a pipe cutter, which is capable of mechanically manually cutting pipes with a maximum diameter of 42 mm.

It consists of handle holders, internal blades made of durable tool steel and a locking bracket, which locks the two handles in the closed non-working position.

If this tool is not available, you can use a regular hacksaw or a strong, sharp knife as a pipe cutter.

Any tool capable of cutting metal-plastic will do, but only a pipe cutter can provide a clean and accurate perpendicular cut. After all, for a hermetically sealed pipe connection, a perfect perpendicular cut is required.

Socket and adjustable wrenches

These wrenches are necessary to dismantle and assemble a metal-plastic pipeline and secure them with nuts, fittings and other threaded connections.

Photo: socket wrench adjustable wrench

open-end wrench

It is used only when necessary, but most often when connecting metal-plastic pipes with metal pipes.

Photo: open-end wrench

Caliber

Using this tool, the cutting planes are centered and chamfered from the inside of the pipe. It is thanks to the caliber that the complete tightness of the connection between the pipe sections and the ends of the fitting is ensured.

Photo: caliber

Press jaws

These tools are needed, for the most part, where couplings are used that need to be pressed with pliers.

Photo: press jaws

Pipe bender

In those places where smooth bends of metal-plastic pipes are required or where it is not possible to cut them, they can be bent using a pipe bender. This way, the pipes will remain intact and there will be no need to cut them, which will increase the service life of the pipes.

Photo: pipe bender

Expander

Using an expander, the necessary expansion of the holes inside the pipes is made for permanent connections.

Photo: expander

Connection methods

There are several ways to connect metal-plastic pipes, which are the most optimal options, ensuring complete sealing at pipeline joints, which means efficient and trouble-free water supply.

But in order to use one or another method of connecting pipes, you must first properly prepare the place for their installation and take into account everything important rules installation of metal-plastic pipes.

Preparatory work consists of planning the place where the pipeline will be installed. To do this, calculate all the dimensions and draw all the lines on the walls or floor, where exactly the sections of pipes, their corners, adapters-fittings and other components will be placed.

Important! The beginning of each pipe line should be laid from the water supply point to the faucet, cistern or radiator. The number of corners, tees or crosses should be as small as possible, otherwise their multitude will slow down the flow of water, and, accordingly, the pressure.

All connecting sections of the pipeline in mandatory should be located in accessible places because they require more frequent inspections and repairs. After the preparation is completed, the assembly of the entire pipeline begins.

Connection with press fittings

In places of turns, corners and various transitions, devices such as fittings are used to connect metal-plastic pipes, which firmly secure the connected sections of the pipeline.

This device is especially convenient when you need to connect the ends of pipes of different diameters. Therefore, fittings that connect pipes with the same diameter are called straight, and those that connect the ends are called transitional.

Press fittings, together with the entire pipeline system, can be laid in a concrete screed, which is much more convenient in installing heated floors, for example, compared to compression fittings. They come in the following configurations:

Nipple with female thread	Nipple with external thread (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 26×1; 32×1	coupling 16; 20; 26; 32
Elbow with internal thread (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 26×1; 32×1	Elbow with external thread (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 26×1; 32×1	Square (connection of two metal-plastic pipes) 16; 20; 26; 32
Tee with female thread (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 26×1; 32×1	Male Tee (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 26×1; 32×1	16; 20; 26; 32 Transition tee from 16–20–16 to 26–32–26
Cross 16; 20; 26; 32	Elbow (water socket) 16×1/2; 20×1/2	Double square for mounting faucets and other appliances 16×1/2; 20×1/2

Various connections with press fittings help to attach pipes to each other in such a way that the connection is then permanent - this ensures complete sealing of the installation, and hence the efficiency of water supply.

Such examples are, as a rule, press fittings with steel or brass ferrules, as well as fittings with a crimp and slide clamp.

Photo: various connections with press fittings

The connection of metal-plastic pipes with a compression press fitting usually occurs in the following sequence:

cut the pipe to the required size using a pipe cutter;

Photo: cutting off the pipe

we process the edges of the cut pipe with a gauge;

Photo: processed with a caliber

Photo: putting a crimp coupling on the pipe

insert the fitting using rubber O-rings (for electrocorrosion);

Photo: inserting the fitting

we crimp the coupling with electric or manual press pliers. When working with electric press jaws, do not place your fingers on the metal parts of the coupling or the tool itself. Work exclusively with rubber gloves and hold the device only by its special plastic handles;

Photo: crimping the coupling with electric or manual press pliers

Photo: the coupling should acquire the bright outlines of the rings

Connections of this kind are based on couplings that must be tightly clamped, and therefore they are considered the most reliable and can safely be used in hidden pipeline communications.

Important! The most important rule when working with press fittings is to crimp the coupling once; re-clamping it with press pliers will lead to cracks, thinning of the material, and then failure of the entire pipeline system.

Connection with compression fittings for metal-plastic pipes

Compression fittings are the simplest mechanism that consists of a fitting, a split ring and a union nut. That is why such a pipe connection is considered unpretentious and economical because it does not require the use of additional special tools.

It is enough to use an ordinary wrench, and if necessary, at the joints with compression fittings, the pipeline can be easily dismantled and the necessary repairs of pipe parts, replacement of gaskets on the fitting fitting and other work can be carried out.

Connections using compression fittings are as follows:

Photo: connection with compression fittings for metal-plastic pipes

When choosing compression fittings, be sure to pay attention to their manufacturer. It is best to choose fittings from the same manufacturer as the metal-plastic pipes you purchased.

Because many manufacturers produce fittings that are not the correct diameters and may not fit your pipes. When installing a pipeline with compression fittings, no press jaws or any other tools are required.

It is enough to use a wrench and, if necessary, a pipe cutter.

With an already installed pipeline, the third pipe with a compression fitting is connected as follows:

Mark with a simple pencil on an existing pipeline, the place where the pipes are cut, where the third pipe will be inserted;

Photo: mark the place where the pipes are cut

Photo: cut the pipe at the marked places

we put corrugated insulation on the pipe (if necessary, but usually this is done so that the pipes do not fog up and condensation does not form on them);

Photo: putting corrugated insulation on the pipe

calibrate the ends of the pipe (mandatory item);

Photo: calibrate the ends of the pipe

we put union nuts and O-rings on the ends of the pipe, and then insert the fittings;

Photo: we put union nuts on the ends of the pipe

Using wrenches, we tighten the nuts that fasten the pipes with fittings.

For ease of working with compression fittings, the length of the pipe sections before and after the cut should be at least 10 cm.

Important! The pipes must be cut at right angles and then calibrated on all sides of the gauge: first, 1 mm of the lead-in chamfer is removed, and then with the other side up to the scoring mark.

Before fitting the pipe onto the fitting, lightly moisten it. When tightening the nuts, do not over-tighten them, because this can quickly strip the threads.

With push fittings

Slip-on fittings are just as easy to install as the previous types of connections. First, the pipe is cut in the right place. Then a coupling is put on its end (or two couplings are put on the two ends).

Therefore, the end of the pipe is treated with an expander to slightly widen the hole in the pipe. Next, the pipe is installed on the fitting, the coupling is clamped using press pliers and pressed onto the fitting.

Here, an important element and feature of the installation is the principle of pressing the sleeve or coupling of a sliding fitting onto the end of the pipe, expanded by an expander, which is put on the fitting.

When you place the compression sleeve on the end of the pipe, it is very important to press the pipe as tightly as possible to the fitting. This is what will ensure the tightness of the connection.

Such methods allow you to connect pipes without welding, glue or any questionable connections, and also to further maintain the integrity of the entire pipeline.

Connection of metal-plastic pipes with metal ones

From time to time, practice shows that when replacing plumbing fixtures in some places, it is necessary to connect metal-plastic sections of the pipeline to metal pipes.

The accuracy and precision of following all step-by-step recommendations is very important here. The most common method is to use a metal-plastic pipe when connecting it to a metal compression fitting.

The work should be done in the following sequence:

Using an open-end wrench, screw the fitting onto a metal pipe (cleaned of rust if the pipe is old). In order to avoid any leaks in the future, use the old method - tow and paint. You need to saturate the tow with paint and wrap it on the pipe thread in a thin layer, and then screw the fitting onto its end;

Photo: screwing a fitting onto a metal pipe

Now start working on the metal-plastic pipe while the paint on the metal one dries. Place the press washer together with the nut on the end of the metal-plastic pipe and calibrate the pipe;

Photo: calibrate the pipe

next, put the end of the metal-plastic pipe on the cone screwed to the metal pipe;

Photo: place the end of a metal-plastic pipe onto a cone screwed to the metal pipe

again use the open-end wrench and tighten the nut so that the washer tightly presses the metal-plastic pipe.

Photo: tighten the nut

With polypropylene pipes

In places where there are connections to boilers, washing machines, heating geysers and other connections that do not require the installation of massive pipes, most often use polypropylene pipes (PPT).

Such pipes are also called plastic because they are made of almost the same plastic. Possible options for connecting such pipes to metal-plastic ones also include devices such as fittings.

These connecting elements perform well both in connections with metal and metal-plastic pipes.

Coupling with internal thread (transition to pipe fittings)	Coupling with external thread (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 25×1; 32×1	coupling 16; 20; 25; 32, etc.
Elbow with internal thread (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 25×1; 32×1	Elbow with external thread (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 25×1; 32×1	Square 45, 90° (connection of two polypropylene pipes) 16; 20; 25; 32, etc.
Tee with female thread (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 25×1; 32×1	Male Tee (transition to pipe fittings) 16×1/2; 20×1/2; 20×3/4; 25×1; 32×1	Tee with identical fittings 16; 20; 25; 32, etc. Transition tee transition to different diameters
Cross 16; 20; 25; 32, etc.	Elbow (water socket) for mounting faucets and other appliances 20×1/2; 25×1/2	Pipe bypass to bypass another pipe when installing in one plane

With radiator

The principle of connecting metal-plastic pipes to radiators mainly consists of using special adapters and fittings, already familiar to us.

There are also several schemes for connecting pipelines and risers to radiators:

the “bottom-down” scheme is used for hidden piping in the floor. If there are thermostats and valves, special adapters must be used that would firmly fix all the necessary connections;

Photo: bottom-down diagram

lateral connection also requires the use of adapters, chrome-plated or brass tees with metric threads;

Photo: side connection

connection from the floor. With this connection scheme, the “spread” of the vertical front pipes is effectively ensured by a telescopic fitting;

Photo: connection with floor exit

corner connection, or “diagonal” pattern. Not only with this method, but also with others, swivel elbows are also used if necessary.

Photo: corner connection

With tap

Just as we looked at connecting metal-plastic pipes with various other pipe materials and types of plumbing fixtures, connections of metal-plastic pipes with taps are used in the same way.

Fittings are also used here, preliminary calibration of the end of the pipe and connection in this order:

you need to unscrew the connecting fitting;
remove plastic or metal lug nuts and O-rings;
put the clamping nut and sealing rings on the metal-plastic pipe;
tightly insert the pipe into the fitting;
Pull the sealing ring and tighten it with a clamping nut;
the other end of the fitting is connected to a check valve, which is pre-installed to the inlet of the faucet itself.

With flexible hose

Such connections are usually made where water supply to a washing machine, boilers and other devices and structures is required. The fittings here should be used with fittings that are specifically designed for flexible hoses.

Important! Also, at the end of the water hose there must be a nut that will secure the entire connection to the fitting.

You need to pay attention to this when you buy this or that hose for your future system.

How to disassemble

It must be said right away that not all types of connections can be disassembled without damage and replacement with new connecting elements.

This depends on what technology for connecting metal-plastic pipes was used, what, for example, fittings were used to connect certain sections of the pipeline.

If press fittings or fittings with sliding couplings were used, which were then pressed using press jaws, then such connections are considered non-separable, and therefore their replacement, if necessary, will be done by completely dismantling and cutting off this section with pieces of pipes.

Then you need new components for connecting fittings, as well as an additional piece of pipe.

If connections were used using compression fittings, then unscrewing the clamping nuts will not be difficult. And, therefore, it will be easy to disassemble the entire area where the pipes are connected.

If it flows

To eliminate leaks at the joints, you must first find and determine the cause and nature of the failure.

check that the connecting nut is not loosely screwed on and tighten it slightly until it stops, but not too much so that the thread does not burst or break;
turn off the water supply, unscrew the fitting and check whether the pipe fits tightly into the fitting or whether the pipe fits tightly when it was pressed onto the fitting. If such a problem is discovered, then the pipe must be inserted all the way, and then also screw everything in the reverse order. But this applies only to collapsible connections;
if you have a compression fitting, then check whether the ferrule fits tightly and if not, then press it again with the press pliers. Just don’t overdo it here, so as not to damage the surface of the metal and prevent it from crumbling or cracking;
if you calibrated the end of the pipe with a knife, then water will flow and seep through the rubber fittings, which cannot fit tightly and move out. This malfunction can be easily eliminated by disassembling the connection and calibrating the end of the pipe with a gauge until the end is smooth and installing everything again in the reverse order;
If the sealing rings are worn out or become unusable, then they should be replaced.

Having carefully studied and considered everything possible options connections of metal-plastic pipes using fittings and all kinds of tools, you can easily correct this or that unfavorable situation with your water supply in the house yourself or repair the pipeline yourself.

Careful preparation for work will also help you to repair or install a metal-plastic pipeline yourself and at the highest level.

Video: Secrets

When replacing water supply pipes, metal-plastic pipes are increasingly being used, since they are inexpensive and quite reliable way pipeline devices.

However, few people still know how, for example, to connect metal-plastic pipes with metal ones. It is the methods of connecting metal-plastic pipes that will be discussed in this article.

Methods of fastening metal-plastic pipes and preparatory work

There are two ways to connect metal-plastic pipes:

using compression fittings;
using press fittings.

The second method, in turn, is also conventionally divided into two types of connections - using crimp couplings and using push-type press fittings.

Before connecting metal-plastic pipes, it is necessary to draw a diagram of the location of pipes, heating devices and plumbing. After this, you will need to prepare the tools and pipes, carefully measuring their length and cutting them into suitable lengths.

The deformed edge of the pipe should be leveled using a calibrator, and the end should be cleaned of burrs and roughness using a round file or a sharpened drill.

Let us consider the methods of connecting metal-plastic pipes and their features in more detail.

Connecting pipes using compression fittings

Design and principle of operation of compression fittings

Compression-type brass fittings consist of components such as a fitting, a split ring and a union nut, while providing a reliable connection of the elements using an ordinary wrench.

By tightening the union nut of the fitting, we thereby compress the press sleeve (split O-ring) on the pipe, thereby achieving the required density between the inner wall of the metal-plastic pipe and the fitting fitting.

Advantages of a compression connection

The advantage of this is that installation does not require the use of special tools and equipment, while it remains possible to dismantle the connection if necessary.

Theoretically, a once-assembled unit can be disassembled and reassembled, but in practice it can be seen that the fitting and connection used for the first time is generally the most reliable.

When connecting pipes with a fitting that has been in use, the sealing gaskets should be replaced.

Pipeline installation using compression fittings

When securing metal-plastic pipes, a minimum number of clamps and clamps will be required, since pipes of this type retain their shape well.

The pipeline can be installed using both a collector and a tee circuit. When using a tee scheme, fittings can be connected to the pipe sequentially or cut in after the pipeline has been laid.

The technology for connecting metal-plastic pipes using compression fittings is as follows:

I align the pipe t, ensuring a straight, even segment before and after the cut of at least 10 cm.
Next, prepare the pipe as described earlier. It is also required to provide a lead-in chamfer at the ends of the pipe of no more than 1 mm.
Place a union nut on the pipe, and then a split ring.
Moisten the fitting.
Place the pipe on the fitting so that its entire end rests against the edge of the fitting.
Screw the union nut onto the fitting by hand until it stops. The nut should go along the thread easily, but if this requires force, it means it is not going along the thread, and further tightening can lead to damage to the thread, which will most likely require replacing the fitting.
Holding the fitting body with one wrench, tighten the union nut with another wrench 1-2.5 turns so that 1 or 2 threaded threads remain visible.
The use of keys with additional leverage and the application of excessive force is not permitted.

For the purpose of insulation, as well as to prevent condensation from settling on the pipes, corrugated hoses, usually made of foamed polyethylene, are put on them. The hose is cut lengthwise with one cut, put on the pipeline and, if necessary, secured with tape.

Installing the corrugation, however, is not a priority and can be done later.

You can watch a video lesson on the installation of thermal protection for metal-plastic pipes by entering the appropriate request on the Internet.

Marking of compression fittings

Fittings are marked according to two indicators:

external diameter of the connected pipes;
type of thread on the fitting.

For example, a nipple-type fitting with internal thread and marking 16×1/2 can be used as a connection means for metal-plastic pipes, on one side of which a 16 mm thread can be attached, on the other - pipe fittings with a 1/2 inch thread .

Connecting pipes using push-on fittings

The connection of metal-plastic pipes using push-in fittings is carried out as follows:

Prepare the pipe for connection and put a coupling on it.
The cleaned edge of the pipe is treated with an expander and flared.
Place the pipe on the fitting fitting, clamp the sleeve in a manual or hydraulic press, press it onto the fitting, and the connection is ready.

The principle of operation of a push-on fitting is simple: by directly pushing the coupling onto the fitting, the pipe is pressed as tightly as possible, thereby ensuring a reliable connection.