Warm water floor - assembly and installation of the collector group

The traditional heating system in the form of radiators was the only source of heat for a long time, but today it is being replaced by heated floors. They are electric and water. The key to efficient operation of water heating is the presence of a collector and its correct installation.

This article will be useful to those who are planning to install heated floors in their home and install the collector themselves. In it we will talk about the existing types of this equipment, their structure and installation method.

Features of the operation of water heated floors

Water heated floors are used as the main or additional source of heat in private homes. The idea of this system is based on laying thermal circuits and pipelines with coolant circulating through them in the screed. The liquid is heated in a boiler and then distributed through floor loops in different rooms. The main feature of the operation of such a system is the need to maintain a low, uniform temperature across a large number of consumers. The coolant comes from the boiler heated to 60 - 70 degrees, such heat from the floors will be uncomfortable for residents. To reduce the temperature, a mixing unit is included in the system or RTL valves (reverse flow regulator) are installed.

The second feature of heated floors is associated with the uneven distribution of coolant throughout the system. The rooms have different areas, which means the contours will be of different lengths. Redistribution occurs at the collector.

Advantages

The manifold heating cabinet has the following features:

the use of a distribution overhead structure can significantly reduce the number of pipes required to connect a heated floor; they do not need to be pulled from the heater, because the collector can be placed in the same room;
In addition to installing a collector, this cabinet can also serve for water supply; it houses a water metering device;
the cabinet mechanism provides the most convenient access to the guide system for repairs and modernization;
and most importantly - safety, a turnkey door will be able to protect the building from children, and they, in turn, will not get burned.

In addition, a neatly painted door looks much more beautiful than a bunch of pipes and valves installed on the wall.

What does the collector group consist of?

The collector has the form of a metal or plastic tube in which the coolant is collected and redistributed along the circuits. The collector group usually consists of two combs: supply and return, a pumping and mixing unit and additional equipment.

On the left is a pumping and mixing unit with a thermal head, on the right is a manifold comb with rotameters and a drain valve.

Collecting combs

The main differences between the supply and return combs are only in the shut-off valves. The heated coolant from the boiler comes to the supply, then the liquid is redistributed between the heating devices. The substance (water, ethylene glycol or propylene glycol) passes through the circuit, gives off heat and returns to the return comb, from where it goes back to the boiler.

Read more about choosing a coolant for a heating system in a separate article.

How it works?

The collector combs have a larger diameter compared to the pipes, because of this the coolant in the distribution block slows down its movement. Distribution occurs through pipes with a smaller flow. One comb can have up to 14 pipes, depending on the number of heating devices. Typically, the supply is equipped with adjusting devices to change the flow of underfloor heating circuits. More coolant will flow into a pipe with a higher throughput, and accordingly the heating devices will heat up more.

Shut-off valve options

To regulate the amount of coolant on the collector, ball valves, valves, flow meters (rotameters), thermostatic push-action valves or servos are used.

Ball valves are shut-off valves with two positions: (open and closed), allowing you to stop the movement of the coolant through a separate pipe of the comb. Ball valves do not allow you to regulate the flow, so it makes sense to use them in heated floors, where the loops are approximately equal in length. They are also placed in front of collectors.

An example of a manifold with ball valves.

The valves allow for stepwise changes in the flow diameter and require manual control of the system.

There are flow meters on the top of the supply comb, and thermostatic valves on the bottom of the return.

Flow meter (rotameter) is a device that measures fluid flow per unit of time. It is a transparent flask with a stem inside; the mechanism of operation of the valves is similar to a regular valve.

The coolant flows along a shorter line with less hydraulic resistance - the flow meter on such loops narrows the passage, and on longer ones it widens it, due to this the floor in different rooms heats up equally.

Thermostatic pressure valves are installed on the return comb of the underfloor heating manifold. They can close or open depending on the return temperature. The TSG valve is equipped with a Eurocone, which allows you to measure the temperature of the liquid in the pipe.

Thermoelectric servo drive is a thermostatic head that can remotely control the operation of the comb valves. Servo drives are divided into normally closed and normally open. In the first case, in the normal position the valve is closed and opens when voltage is applied. The servo drive is connected to a thermostat, which is located in the room and responds to changes in air temperature.

The thermoelectric servo drive should not be confused with RTL valves. The first reacts to changes in room temperature, the second is adjusted to the temperature of the coolant.

Thermoelectric head with servo drive.

Device with 2-way supply valves

The two-valve manifold assembly has the following features:

Two-valve manifold assembly kit

cold and hot coolant are constantly mixed. This prevents overheating of the device and extends its service life;
the temperature change occurs smoothly, since 2-way valves have a small throughput;
are not used in small rooms whose area is less than 200 square meters. m.

Should I assemble a collector or buy a ready-made one?

Collectors can be prefabricated, ready-welded or homemade. Let's consider their advantages and disadvantages.

Ready welded

They are usually produced in the form of supply and return combs welded together with a specified number of pipes.

Advantages

Fast installation - no need to assemble fasteners.
Minimum qualification requirements for an installer

Flaws

Difficult to configure for a specific system.
The number of pipes may not meet the needs, in which case they will have to be blocked off with plugs and not used.
The collector can be equipped with elements that are unnecessary for a particular heating system. For example, it may have a hydraulic distributor (hydraulic arrow), which is only useful in networks with a large number of pumps.
The return and feed combs may be welded together, making it difficult to attach separate loops to them. The pipes on factory mixers are usually located at the same distance from each other, but this is not always convenient.

Homemade

You can make a collector with your own hands from available materials: steel pipes with a round or square cross-section. To do this, holes are cut in them and pipes are welded. Couplings are made from round sections of smaller diameter.

Advantages

Making a collector with your own hands is profitable from a financial point of view.
You can make a drawing and manufacture an individual manifold for a specific system.

Flaws

To perform this job, you will need skills in working with a welding machine.
It will take more time.
The non-separable design makes it difficult to repair and replace individual elements.

Prefabricated

Such distribution units are assembled from factory parts, which are purchased separately or as a kit. They will be discussed further.

Advantages

There is variability when designing a collector unit for a specific heating system.
Does not require special skills or equipment for installation.
Possibility of separate dismantling of feed and return combs.
High installation speed.

Flaws

Components from different manufacturers may not fit together.
This option usually costs more.

Preparing the base

The primary task when preparing the base for the floor is to remove the old screed, regardless of its type. When the old screed is removed, you need to start leveling the base level. The base for a heated floor must be strictly horizontal - height differences of no more than 1 cm are allowed over the entire area of the base.

The horizontal surface is covered with waterproofing material, and it must be laid hermetically and with a small tolerance along all edges. A special tape is attached along the perimeter of the walls at floor level, which is necessary to compensate for the thermal expansion of the floor during heating operation. If the underfloor heating system includes several separate circuits, then there must be the same tape between them.

How to install a rotameter on a manifold comb

Rotameters are often used on underfloor heating manifolds; they are necessary to control flow. Depending on the model, the device can be adjusted to different flow rates from 0 to 5 l/min. The setting is made only when the pump is turned on. It is necessary to remove the decorative protective cap and tighten the fixing nut into the desired position. After setting up the flow meter, the plug is installed in place.

Rotameters differ for the return comb and the feed comb. Inside the glass flask of the device there is a rod with a plate. In the non-working state, the rod plate is pressed to the zero value by a spring. The coolant is always supplied under the valve seat, since the flow opens the valve. On reverse rotameters the rod is at the bottom, and on feed rotameters it is at the top (the numbers will increase from above).

Differences between the rotameter on the feed and return combs.

If you confuse the supply and return rotameter, the coolant flow will press the rod against the seat, and the system will not work. Some devices do not allow you to record the required flow rate, but only measure its value; to distribute flows along the contours of heated floors, it is advisable to use the first option.

Fastening technique

Each type of manifold cabinet has its own mounting nuances, which are worth remembering when installing them.

Built-in

If the deepening was made during construction, there will be no difficulties with installation. When planning a heated floor and installing a cabinet, carry out the following actions:

selecting a location for the collector, which is assembled no lower than the floor height, since problems with heat supply are possible;
mark the wall for pipe collections;
using a wall chaser to make holes for a cabinet or pipeline;
The structure is fixed into the wall niche and connected with anchors on the sides of the box;
place the collector, fasten the circuits and heat supply;
the gap between the cabinet and the wall is covered with mortar, then puttied.

Outer

Installation is a little easier:

select a location for the structure;
place the box;
aligned according to the drawn marks;
drill holes for anchors with a hammer drill, screw the box together with screws;
install the collector, connect the circuits;
the wall remains the same - the cladding is not touched.

The cabinets are installed quickly. The recess does not delay the fastening process. After connection, there will be no problems with adjusting the system and water supply.

Mixing unit

The mixing unit can be used without a collector.

The mixing unit is often included in the collector group. Its operating principle is based on combining the supply and return flows. After passing through the heated floor loop, the medium usually has a temperature of about 30 degrees; at the mixing unit it flows into the supply flow, which allows you to get a comfortable temperature of 40 degrees.

There are many options for implementing this unit: using a three- or two-way valve, using thermostatic valves, etc. Mixers can also be prefabricated or factory-made.

The mixer usually has a thermostatic valve that measures the temperature of the medium. It is equipped with an overhead or cap sleeve. The first is simply glued to the pipe, the second is inserted into the line itself.

A three-way valve with a thermal head is installed in front of the pump. It is also useful to install a coarse filter on the supply before it.

A three-way valve is installed on the supply side; using a thermostatic head, the element allows you to control two flows. There are mixing valves and distribution valves. The first one receives two streams from different sources, combines them into one and sends them along the required highway. The distribution valve receives one flow, which is distributed through several circuits. These elements are used not only to regulate the temperature of the coolant, but also to protect the boiler to prevent idling and overheating. However, the valve installation and layout will not be the same as when used in combination with a manifold.

A mixer with a two-way valve; on the bypass it is useful to install a hidden valve under a hexagon instead of an element with a handle.

Bypass is a channel between the return and supply combs; it creates a small circle and prevents the pump from working at a dead end when one of the lines is closed.

The two-way valve is equipped with a thermostatic head and controls the flow in only one direction. When using this element in a mixing unit, an additional bypass valve will be required. In most cases, shut-off valves are placed under the hexagon. Ball valves cannot be used on this unit due to the impossibility of precise adjustment; it is also not recommended to install a valve with a handle, since someone could accidentally mess up the entire system setting.

The mixing unit is installed after the collector. A pump is placed between the collector and the boiler, which ensures movement in a small circle. The three-way mixing valve is installed on the supply line, the distribution valve - on the return line.

Location of two-way and three-way valves in the heating system

Task	Two way valve	Three-way valve (distribution)	Three-way valve (mixing)
Boiler protection	—	Innings	Return
Temperature regulation	Innings	Return	Innings

The mixing unit on a two-way valve can always be distinguished from a three-way valve by the presence of a valve on the bypass.

Adjusting the operation of the mixer using the example of a two-way valve

In a three-way valve, the flow is always open: if one plug closes, the other opens. In a mixer with a two-way shut-off device, only one plug closes; it works as follows: the thermal head determined that the temperature of the medium is lower than necessary, pressed the rod, the valve opened, and a portion passed into the manifold, mixing with the liquid from the return. When the temperature has reached the required values, the thermal head begins to close: the flow from the supply decreases, the flow from the bypass increases.

The longer the heating circuit of the floor, the more the bypass valve is closed.

The bypass valve has a hidden valve for a hex key. When setting up the system, you need to close the thermostatic valve and open the balancing valve. The rotameters are adjusted, then the valve on the bypass is gradually closed until the rotameter rod begins to show that the coolant is becoming less. Fully open the thermostatic valve and tighten the balancing valve again. As soon as the rotameter plates lower or rise when turning the key on the bypass valve, balancing stops.

Installation of the first panel of vinyl siding

Work is carried out from the rear facade to the front, from the rear corners to the front. This way, the joints of the panels, when they are overlapped along the length, will be less noticeable. The lock of the first row panel, located in its lower part, is inserted into the corresponding lock of the starting strip. The upper part of the panel is attached to the sheathing. The siding cannot be stretched too tightly, otherwise it will burst due to thermal expansion.

If installation is carried out in the cold season, a gap of about 9 mm is left between the panels. During summer installation, it is reduced to 6 mm in warm weather and to 3–4 mm in hot weather. As already noted in the first chapter, the dimensions of the temperature gaps are indicated for solid panels. Cut parts also need a gap, but of a smaller size. If the ambient temperature drops below –10 °C, vinyl siding cannot be installed. Vinyl siding can be joined lengthwise in two ways: overlapping and using an H-profile. Overlapping joining. The nail strip and the locking part of the panels are cut so that the panels can be mounted with an overlap of about 25 mm.

Docking using an H-profile. The upper part of the H-profile is lowered below the soffit or cornice by 3 mm. This will be the temperature gap. At the bottom, the H-profile is lowered 6 mm below the edge of the starting strip. If there is a base, floor, porch or other limiter under the H-profile, a temperature gap of 6 mm is left between the end of the profile and the limiter.

If the length of one H-profile is not enough, install two overlapping profiles. The overlap joining of H-profiles is carried out according to the same principle as the joining of two corner profiles. The upper one is mounted overlapping the lower one. The H-profile visually emphasizes the vertical section of ordinary siding panels and makes them more noticeable. Therefore, it must be mounted in such a way that it does not spoil the appearance of the cladding, but fits organically into it.

Do you need a hydraulic gun?

A hydraulic separator (hydraulic arrow) is a device that is usually placed between the boiler and the collector; it provides zero resistance in this area. Visually, the element is a hollow pipe with 4 pipes: on one side, two are intended for the boiler, on the other, for the collector. The question of installing a hydraulic separator arises when there is a need to install more than 4 pumps and more than 1 boiler.

The hydraulic arrow can be fixed vertically or horizontally, it does not matter. The first option is often chosen, as it simplifies the installation of the air vent in the upper part. A tap can be attached to the bottom to remove sludge.

Often in articles this device is attributed properties that it does not possess. We list the tasks for which you should not buy a hydraulic gun.

Does not increase boiler efficiency
Does not reduce fuel costs
Does not protect against heat stroke
You still need to select pumps for each circuit separately.
Not intended for air bleeding or sludge protection.

The hydraulic arrow can worsen the operation of the system if the pumps are incorrectly selected. For example, a boiler unit is much inferior to the total power of devices on other circuits. As a result, the coolant reaches the comb already cold due to mixing with the reverse flow.

Are a manifold and mixing unit required?

In a small house, a heated floor may not take up so much, in which case the costs of a collector and mixer will not be worth it. The simplest solution would be to install a heated floor with one or two circuits, controlled by a TSG thermal head or an RTL tap. Regulation in this circuit occurs by limiting the temperature on the return flow.

The RTL valve is not intended for installation on a manifold; it has high hydraulic resistance. Due to the large size of the head, it is inconvenient to screw the element onto a distribution unit with a large number of adjacent circuits. This also makes it impossible to use built-in plumbing cabinets. It is not recommended to install RTL cranes on a circuit longer than 70 meters. The thermal head is usually placed in a plastic box that is hung on the wall.

The TSG head also limits the return flow, but has a Eurocone, so it can be installed on the return of the manifold. The actuator acts on the stem, and not on the valve itself. In this case, the head is occupied by the working valve of the manifold, because of this, installation of the servo drive becomes impossible. The absence of resistance makes it possible to install a longer circuit.

Installation and connection rules

It is best to select and install a collector at the stage of design and installation of the heating system.

Such intermediate structures are installed in rooms protected from excess humidity. Most often, space is allocated for these purposes in the hallway, pantry or dressing room.

It is advisable to place the collector block in a metal cabinet specially designed for this purpose, equipped with holes in the side walls for pipe outlets

On sale there are overhead and built-in models of metal cabinets. Each model is equipped with a door and stampings on the sides.

In the absence of the opportunity to install a metal cabinet, it is easier to do it by fixing the device directly to the wall. The niche for arranging the collector block is placed at a low height relative to the floor.

There are essentially no generally accepted instructions for installing collector distribution circuits. But there are a number of main points regarding which experts have come to a common denominator:

Availability of expansion tank. The volume of the structural element must be at least 10% of the total amount of water in the system.
The presence of a circulation pump for each laid circuit. Regarding this element, not all experts are unanimous in their opinion. But still, if you plan to use several independent circuits, it is worth installing a separate unit for each of them.

An expansion tank is placed in front of the circulation pump on the return line. Thanks to this, it becomes less vulnerable to the turbulence of water flows that often occur in this place.

If a hydraulic arrow is used, the tank is mounted in front of the main pump, the main task of which is to ensure circulation in the small circuit.

The location of the circulation pump is not important. But, as practice shows, the service life of the device is somewhat higher on the “return” route.

The main thing during installation is to position the shaft strictly horizontally. If this condition is not met, the very first bubble of accumulated air will leave the unit without cooling and lubrication.

The process of assembling and connecting the collector system is clearly presented in the video block.

Work progress

We install the mixer on the return comb, if an assembled factory element is used, and tighten the union nut (American) with a wrench.
A mixer is installed on the child’s feed using the same principle.
We install air vents for return and supply.
Plugs are installed at the ends opposite from the mixer; they should be tightened with a wrench.
A drain valve is installed on the comb; it is usually located under the air vent; they are designed to bleed gases from the manifold.
For convenience, you can screw the fitting into the comb separately and then install the tap on it.
A pump is attached between the return mixer and the supply comb.
The fastening element is assembled; all manufacturers have their own in the form of runners or strips. If a homemade manifold is used, then the fasteners are made from improvised materials. The holders are first mounted on the combs and only then on the wall.
The combs should be at the same distance from each other so that they are parallel on the wall. This is not a technical requirement, but more of an aesthetic consideration. To align the combs, they are first fixed to the fasteners on one side, then the same distance is measured from the other end. This is easy to achieve in short manifolds. Typically, for many manufacturers, the standard distance between combs should be 21.5 cm.
In practice, from the point of view of system operation, it does not matter which comb is on top. In most cases, a supply distributor is placed there, but nothing will change if you put it below. The main thing is not to confuse the supply and return rotameters.
The plug is removed from the factory return mixing unit, the thermostatic head is screwed to it, and the measuring sleeve is inserted into the supply comb mixer.
Two mounting strips are fixed to the wall. Fasteners and hardware are selected depending on the base material. It is advisable to fix the collector at 4 points.
The connection is made using a Eurocone. A nut is put on the pipe, then a ring, and a thrust bushing is placed in the hole. Fixation is carried out using two keys. One fixes the hexagon, the other tightens the nut. You need to do this carefully so as not to rip off the fitting.
The contours are drawn in increments of 100 mm.
Installation of the circuit is completed by connecting the line to the return comb. Pipes must be placed in an insulating casing. The system is filled through drain and fill valves. The ball valves on the manifold are closed.

Varieties

There are 2 types of manifold cabinets:

built-in devices - placed in a niche made in the thickness of the wall or hidden under a lining of plasterboard or lining. Typically, the sides of these models are not painted, since they contain outlet and fastening spans. Typically, the depth of the device is 120 mm, the width is 465-1900 mm, and the height is almost 650 mm. To simplify the designation on the niche and to accommodate different sizes of manifolds in the cabinet, certain built-in devices are equipped with retractable legs. Using this option, it is possible to raise the height of the structure to 100 mm;
external manifold cabinet - these models are the easiest to install, as they are mounted on the wall surface. On the sides, the structure is coated with a special corrosion-resistant agent or powder paint. The outlet slots are initially covered with easily removable metal plates. The external wall-mounted manifold cabinet has dimensions almost identical to the parameters of the built-in structures. It is also possible to adjust the height using extension legs.