What is a chimney draft stabilizer for?

The principle of operation of the stabilizer

If the draft force in the system begins to exceed its optimal values, then a valve opens in the regulator, which lowers the pressure and thermal lifting force due to the air coming from the room and mixing with the flue gases. The valve will remain open until the temperature drops and reaches the optimum level. Further, the valve will automatically close, the chimney system will continue its proper functioning.

This method of maintaining traction in the normal range is simple and effective. Fuel in the furnace or boiler will be burned evenly, and spent sparingly.

Installing a chimney draft stabilizer provides the following benefits:

improving the safety of operation of the chimney system;
reducing the amount of harmful substances emitted into the atmosphere;
better circulation of air flows when the valve is kept ajar;
the possibility of functioning both on forced and natural draft;
uniform combustion of fuel in the boiler, which makes it impossible to overheat the chimney;
protection against strong gusts of wind;
the absence of a smell of burning in the room;
increase in service life of the channel for an output of a smoke;
prevention of heat loss;
possibility of installation in modern low-temperature boilers;
ensuring fuel economy by 15-20%.

Advantages and disadvantages

Equipping a heat generating unit with a draft regulator is considered the most effective way to ensure uniform fuel combustion. This is a guarantee of energy saving and significant savings in combustible resources. Also among the advantages of installing a pressure stabilizer in the chimney, the following points are noted:

the efficiency and safety of the system as a whole is ensured, since the fuel burns evenly and overheating of the chimney is excluded, which leads to an increase in its service life;
the efficiency of heating equipment increases, the level of heat loss is leveled, energy savings are up to 15%;
the possibility of penetration of smoke and burning into the room is excluded;
the level of emissions of harmful compounds into the atmosphere is qualitatively reduced.

Also impressive are the equally impressive capabilities of the chimney stabilizer both with natural draft and with forced draft.

It is noteworthy that the automatic draft force regulator allows you to connect new models of low-temperature boilers to the old chimney system.

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The device and purpose of the stabilizer

The draft stabilizer is an additional insert on the chimney with a damper, with which you can adjust the intensity of fuel combustion and the draft force in the pipe. A draft stabilizer is installed only on low-temperature heating equipment, where the maximum heating of the exhaust gases does not exceed 500 degrees.

Purpose of the traction stabilizer:

to reduce the rate of removal of products of combustion of the furnace;
to prevent the formation of reverse draft in the pipe and the throwing of smoke into the room;
extend the life of the chimney by reducing the temperature of the emissions;
increase the fire safety of heating equipment by preventing the emission of sparks and flames from the pipe;
reduce fuel consumption;
increase the efficiency of the furnace.

A draft stabilizer is installed in three locations and only in the boiler room:

The first option is above the outlet pipe of the furnace on the first vertical pipe section. The distance from the stabilizer to the horizontal section is 40-60 cm.
The second option is at the level of the chimney outlet from the furnace, but not lower than 40 cm from the floor level.
The third option is shown in the diagram.

What is a chimney draft stabilizer for?

The smoke regulator is an additional entrance to the chimney for air suction. The device is a horizontally oriented branch pipe, one end of which is closed by a vertical movable damper, and the other is built into the chimney. The damper must exactly match the inner diameter of the nozzle so that no air is drawn in in the closed position.

The damper is the main working part of the draft stabilizer. It can be attached to the case on a movable axis in the upper part, which is typical for factory devices. Homemade dampers are usually mounted on the axis through the diameter. To prevent it from tipping inward, latches are placed at the bottom. The device is mounted on a vertical pipe, without tilt. On a finished sandwich pipe, it is convenient to do this through a regular tee.

When traction is not enough

Methods for determining thrust

If you do not have an anemometer, use one of the popular methods for determining chimney draft:

Smoke. The most obvious sign of a lack of draft is the presence of a small amount of smoke inside the room, a large amount of smoke indicates a high risk of ignition and the risk of food poisoning.
Flame color. By the color of the flame, you can understand the level of thrust. If the flame inside the furnace has a white tint and cracks when burning, then the draft is very powerful. An orange-red color indicates a lack of traction. If the chimney is made correctly, the flame should have an even golden color that fades into yellow.
With a match. It is necessary to bring a lit match to the heater. If the flame deviates towards the furnace, then there is a draft. If it remains flat, then you can be sure that there is traction, but of medium magnitude. When the flame deviates in the opposite direction from the furnace, there is a reverse draft in the chimney.
With a mirror. Another way to check chimney draft is to place a small mirror against the stove. The appearance of condensation on the surface of the mirror indicates that the removal of smoke is difficult.

Attention!

The pressure difference between outdoors and indoors is the basis for creating draft inside the chimney. The temperature in the heated room is higher than outside, and, consequently, the pressure created by it inside the room is greater. Hot air, supported by colder air from below, is squeezed out into a zone with lower pressure, that is, into the atmosphere. During measurements taken in the summer, the temperature difference is the least striking, therefore the draft will be worse and the measurement results may be low compared to the winter period.

Causes of malfunctions

After making sure that there is not enough draft inside the chimney, it is necessary to identify and correct the possible cause. Professionals say that the most common causes of flue duct failures are.

Design error

To make a choice of a chimney pipe, it is necessary to focus on the volume of the furnace. If the size is less than the calculated parameter, then a weak chimney will not allow smoke to leave the room.

Short pipe length

A pipe length of less than 5 m does not make a significant difference between indoor and outdoor pressure, which creates a weak draft.

Incorrect location of the chimney pipe

The stove maker advises laying the chimney vertically, as tight corners keep the smoke inside the chimney, reducing draft.

Long horizontal sections

If when laying the chimney it is not possible to avoid horizontal sections, make sure that their length does not exceed 100 cm, otherwise, this will need a reinforcement.

Getting into the wind support zone

If there is a tall building near the house, it blocks the chimney from the wind, preventing the chimney system from functioning properly.

Weather conditions

Often, a decrease in draft occurs due to a decrease in atmospheric pressure, moisture entering the chimney due to rain, fog or snow. But this is not critical, because all these are temporary phenomena.

How to make a traction stabilizer with your own hands

To make a draft stabilizer with your own hands, you will need to prepare tools for working with stainless metal and material for making the regulator itself.

For work you will need:

Welding machine for working with stainless steel. It can be a gas welding machine or an inverter machine that runs on direct current.
Electrodes on a stainless steel diameter 4 or argon for gas welding.
Bulgarian, cutting and grinding wheel.

Materials for the manufacture of a traction stabilizer:

Metal sheet made of AISI 304 steel (similar to 08X18H10) or AISI 321 (similar to 08X18H10T). Metal thickness 10 mm.
Bolts, nuts, metal rod with a diameter of 10 mm - all made of stainless, heat-resistant steel.

The installation scheme is as follows:

From a sheet of metal, it is required to weld a branch pipe - the regulator body. Calculate the diameter based on the diameter of your chimney. You will need to put the stabilizer on a tee or branch pipe extending from the main pipe. Therefore, the inner diameter of the stabilizer must match the outer diameter of the tee. Usually it is 115 mm, but it can be more.
The metal for the body should be cut with the calculation of overlap welding with a seam width of 1 cm.
The cut sheet is twisted and welded. The seam is cleaned to smoothness from the outside and inside.
At a distance of 40 mm from the edge at the end of the housing, roll a restrictive barrier. It will serve as a stopper when mounting the device on the pipe.
At the other end of the body, in the lower part, weld limiters to prevent the damper from tipping inward. In the upper part or in the middle (depending on the shape of the damper), fasteners for the rotary axis are welded.
A shutter is cut out of metal. Its size is equal to the internal diameter of the outlet of your case or corresponds to the contours of the outlet if you decide to reduce it.
A hole is drilled at the bottom of the damper for the adjusting bolt.
In the middle (for a symmetrical damper) or in the upper part (for an expanding form), a rotary axis is welded.
Install the shutter on the body.
Install the traction stabilizer on the pipe.

When installing the stabilizer on the pipe, grease the contact points of the nozzles with a heat-resistant sealant. This will make the connection stronger and tighter.

Draft regulator models

Today on the market there is a wide variety of models of chimney draft regulators produced by various manufacturers.

Consider the most popular and in demand:

RCO. Models of this series are fixed with crimp clamps and only to a round pipe. They found their application for chimneys with a circular cross section along the axis of the pipe. The chimney draft stabilizer is installed at the very end of the pipe. Given the fact that modern chimneys usually have a rounded shape of pipes, such regulators have gained wide popularity. Such devices are the easiest to install.
RCR. This stabilizer is installed directly on the chimney and is fastened with special clamps with the possibility of regulation in the range of 120-200 mm and is installed at the boiler outlet. The harsh domestic climate suggests the use of such regulators for chimney pipes made of ceramics, steel and asbestos. Chimneys with a draft regulator in the range of 10-35 Pa cannot boast of high quality, however, if necessary, they can be mounted.

RCR series chimney draft regulator with adjustable collar

R.C.P. With draft regulator in the range of 10-35 Pa. The installation of such a device is carried out by applying and fixing the regulator to a flat surface. The chimney draft regulator for fastening is provided with hidden holes in each corner.

Chimney draft regulator series RCP for surface mounting

R.C.W. This regulator with a draft regulation range of 10-32 Pa has established itself as a good draft regulator in stoves, boilers, fireplaces.Stainless steel is used to make the case, thanks to which you can fix the device with glue, a special solution. You can also use the expanding springs and fix it on the ventilation grille.

RCW series chimney draft regulator for brick chimneys

Summing up all of the above, it is worth noting once again that the chimney draft regulator is a very important element of the heating unit, which most directly affects the functioning of the entire heating system.

Ways to increase chimney draft

The purpose of the draft regulator is to extinguish excessive vacuum in the chimney. The stabilizer cannot increase thrust. What to do when traction is clearly insufficient?

To increase traction, do the following:

Check if the chimney channel is clogged with soot, clean it.
Check whether there is air access to the room or air supply from the street to the furnace of the heating unit. If necessary, open a window or run a pipe to take clean air from the street.
They analyze whether the pipe is sufficiently insulated, whether the insulation is wet. In the case of modern ceramic or sandwich pipes, insulation can be considered sufficient; when insulating steel pipes with your own hands, unpleasant surprises are possible. It is also desirable to insulate traditional brick pipes.
Find out if there is a deflector on the top of the pipe. Often, installing a deflector solves the problem.

If all the searches did not lead to a solution to the problem, it is worth inviting an experienced heating engineer - the safety of the family is above all.

If you have changed the heating unit to a more modern one (or moved the stove or fireplace), then you must:

Calculate the minimum length and cross-sectional area of the hog, depending on the power of the heater (see my article on calculating the chimney).
Consider the required height of the pipe, depending on the location relative to the ridge and the zone of wind support of tall buildings and large trees.
If the chimney is of insufficient height and cross-sectional area, then either build it up or install a smoke exhauster - a special fan. It is installed on the pipe head.
If the old pipe has a section that is much larger than the calculated one, this problem is eliminated by using a gate or installing an insert. If the pipe is too long, you can also use a gate.

When replacing an old stove or fireplace with a modern boiler, the pipe will most likely have to be upgraded, since modern boilers have high efficiency, aggressive condensate and low flue gas temperatures. Even solid fuel modern units have a lower smoke temperature than older wood stoves.