Do-it-yourself chimney damper - drawings and instructions

Here you will learn:

What is a gate valve
Functions, purpose and characteristics
Main types of gate valves
Making a gate valve with your own hands
Tips for choosing a gate valve
Installation features
Gate maintenance

Do-it-yourself chimney damper - the drawings of this device are very simple. The gate can be made of a retractable or throttle type. The material for making the gate is cast iron or steel.

What is a gate valve

The German word Schieber in Russian has not changed either its pronunciation or meaning. If we talk specifically about stove heating, then a damper, as well as a damper, is a shut-off device that blocks the chimney channel.

When arranging a smoke exhaust duct, a valve is installed in the upper part of the base, which is located in the room, so that, if necessary, it is possible to manually regulate the movement of gases, and at the same time the quality of draft.

This is what the gate looks like when extended. When retracted (when the stove is already heated), the valve is almost invisible, only its “eye” protrudes outward.

A damper on the chimney duct is required for the traditional version of a brick stove. By retracting it partially or completely, you can reduce the draft or block the movement of heated gases.

The damper is fully retracted when the stove is heated and gases harmful to health stop flowing into the channel. There are known cases of deaths of people who were burned by a stove that was “closed” early.

If you are late in closing the damper, the heat from the heated bricks will go into the pipe, and the temperature in the room will quickly drop. A timely retracted damper is a guarantee that the house will be warm for at least a day. As you know, in village houses during the cold season the stove has to be lit every morning.

Factory-produced steel gate valve with a diameter of 200 mm. To simplify installation, it is sold together with a piece of steel pipe, built-in.

There is an opinion that dampers, which are mandatory for brick stoves, are absolutely not needed for steel stoves (although they are offered by manufacturers), as well as for models with an installed deflector.

The argument against their use is the fact that the chimney quickly becomes clogged with soot when the damper is closed. Its upper part is cooled by cold air entering the pipe, which, when in contact with a hot steel pipe, forms a large amount of condensate. This situation requires more frequent chimney cleaning.

Functions, purpose and characteristics

The damper is a partition that is located inside the chimney. It follows the shape and area of its cross-section and, when closed, almost completely covers it. Changing the position of the damper allows you to increase or decrease the opening of the chimney pipe, increasing or decreasing the air flow. Using the damper, you can stop the movement of air after lighting the stove.

The gate valve is a thin metal plate that is manually adjusted using a special handle. The latter is located outside the chimney pipe so that the user can manually adjust the position of the plate.

Depending on the design and type of damper, it is installed using a special metal frame, or is inserted inside the pipe and fixed with an axial rod.

Important! Do not assume that the valve completely seals the pipe in the “closed” position. According to fire safety requirements, the damper must have a small hole through which weak gas exchange occurs.

The damper in the chimney performs the following functions:

increases traction force in difficult weather conditions;
increases the intensity of combustion in the furnace due to increased oxygen flow;
reduces draft when there is a strong hum in the chimney during strong winds;
saves fuel by reducing combustion intensity;
prevents heat loss after the heater has warmed up.

Very important! You can close the chimney with a damper only after the wood has completely burned and the flame has gone out. If you close the damper prematurely, this can lead to a dangerous situation due to the release of large amounts of carbon monoxide into the room. If the damper is closed too late, the efficiency of the furnace will be reduced, because Most of the heat will go out through the chimney.

Differences between retractable and rotary gates

So far we have been talking about the retractable type of damper on a stove chimney, although there is another type - a rotary one. Let's look at how they differ.

The purpose of both types is the same - to partially or completely block the flow of flue/heated gases. The differences relate to the design.

A retractable model is a metal plate that is fixed in a frame and moves along guides in a horizontal position. There are no strict requirements for the dimensions of the device, since they must correspond to the cross-section of the chimney and completely depend on its parameters.

Thus, the valve consists of two main parts:

frame , which is fixed in the smoke exhaust duct and is motionless;
plate moving inside the frame.

Typically, both parts are made from the same material to maintain performance when heated or cooled.

A properly designed and installed damper should never completely block a stove chimney. A small gap is necessary for fire safety purposes.

The design of the rotary (throttle) gate does not extend, but rotates along an axis, as the name suggests.

A round or rectangular plate (depending on the cross-section of the chimney) is fixed on a metal rod, the free end of which extends beyond the channel and serves as an adjustment tool.

The simplest model of a rotary gate with a diameter of 120 mm. Manufacturing material – stainless steel. The smoke exhaust channel is closed by turning the handle with a curved end

Gate valves are considered more reliable and wear-resistant devices. The weak point of the rotary devices is the connection between the rod and the plate, which becomes loose over time and renders the valve unusable.

Main types of gate valves

Horizontal retractable gate. The plate located inside the damper extends, due to which the cross-sectional area of the chimney is adjusted. Typically, this type of valve is used for installation in brick chimneys. Often small holes are made on the surface of the plate so that even in the closed position of the gate, it does not block the smoke channel 100%. This complies with fire safety regulations. The advantage of this type of device is ease of installation.

Rotary gate. It is also called a “throttle valve”, which is a metal plate mounted on a rotating axis. The axis, in turn, is attached inside the chimney pipe. This device has a removable rotating disk, but with prolonged use it may become unusable. However, the design of the rotating mechanism allows you to repair and replace it yourself. The advantage of this type of device is its ease of operation. This type of gate does not require constant monitoring by the home owner.

Due to the complexity of the DIY design, the rotating mechanism is less often used when laying a fireplace or stove.

The gate design is necessary for wood-burning stoves and heating devices operating on any solid fuel.

As for gas boilers and liquid fuel boilers, here the damper rather plays the role of protecting the chimney from precipitation.

Therefore, for a gas boiler, the most practical solution would be to install a rotary mechanism. The temperature of the exhaust gases is less low than when using solid fuel, so the operation of such a mechanism will be the most convenient.

Valve on an insulated chimney

But it is better to refuse to install a rotary mechanism in the bathhouse. The fact is that it will partially allow steam to pass through when closed. And when open, such a mechanism is difficult to clean.

Made of stainless steel, the gate mechanism will not completely block the chimney, but will eliminate the possibility of flames escaping through the ash pan into the room.

There are three options for installing the gate.

Installing a damper in a fireplace insert. To do this, the damper is mounted at a distance of 1 meter from the heating device, which ensures simple operation.
The “pipe to pipe” option involves combining the damper with other elements of the heating structure without the additional use of fasteners.
Installation of a gate valve in a ventilation pipe. But this option is usually used to protect the fan motor from overheating during operation.

When purchasing ready-made chimneys, the kit will most likely be equipped with a gate valve, which simply needs to be installed according to the instructions.

But even if the finished kit does not come with this element, you can easily make the gate yourself by choosing the most optimal mechanism option for yourself.

Advantages and disadvantages

Like any engineering solution, a gate has a number of advantages and disadvantages.

Pros:

Possibility of traction control;
Fuel economy;
Dampers help retain heat.

Minuses:

The devices make it difficult to clean chimneys;
If installed incorrectly, the gate may jam and negatively affect the movement of gases;
To make the correct adjustment, you must have some knowledge in the field of smoke exhaust systems.

Differences between retractable and rotary gates

The retractable damper allows you to adjust the working cross-section of the chimney, while the rotary damper only allows you to open or close the pipe. Of course, some tricks are possible - such as securing the hog in an intermediate position in different ways, but the factory equipment does not provide for this. In addition, the rotary gate complicates mechanical cleaning of the pipe.

The hog is often installed in metal chimneys, and the retractable one is installed in brick chimneys.

Installing a damper on a chimney

Today, there are two main ways to install a damper on a chimney:

Installation in a fireplace insert. This installation option implies the location of the gate product in close proximity to the heating equipment. As a rule, in this case the distance from the damper to the heating apparatus is 1 meter. This arrangement is very convenient for regulating the valve.
Connection with other elements of the heating system. In this case, there is no need to use additional locking elements, so this option is quite common. This type of installation can also be called “pipe to pipe”.

Helpful information! In addition, it is worth noting that the gate product can also be installed in the ventilation system. A gate valve for ventilation is necessary to prevent the fan motor from overheating. The fan motor may overheat during shutdown.

The above options for using valves for chimneys and ventilation systems are used everywhere. It is worth noting that today you can find a huge variety of stoves and fireplaces, which differ from each other from a constructive point of view. This variety of heating devices also influenced the range of gate valves. Therefore, the choice of a damper for a chimney depends entirely on the characteristics of the heating device and the chimney design in a particular case.

Making a gate valve with your own hands

Gate drawing

Both a retractable and a rotary gate can be made independently if you have a welding machine and a grinder. Assembling both structures is not difficult, the main thing here is the accuracy of the measurements. If the valve fits too tightly into the pipe, it may jam when exposed to high temperatures. If you leave a large gap between the plate and the pipe, this will make it difficult to adjust the draft.

Manufacturing of a retractable gate

Retractable gate

The design of the gate consists of the valve itself and the guide frame. First you need to measure the internal cross-section of the pipe or brick chimney. According to measurements, a rectangular valve is cut out of sheet steel 4-5 mm thick. On one side, a longitudinal fold 20-30 mm wide is made to make it easier to pull out the flap. All cuts are carefully polished, simultaneously reducing the size of the product by 1-2 mm on each side. This will ensure free movement of the damper inside the chimney.

If the damper is installed in a brick chimney, the frame can be made of thick steel wire, for example, with a diameter of 6 mm. To do this, the wire is simply bent in a U shape to fit the hole.

Gate diagram

If the chimney is steel and has a rectangular shape, the frame is made of a steel strip 2 mm thick and 30-35 mm wide. The strip is bent lengthwise, leaving a gap along the thickness of the plate, then cut in two places at an angle of 45 degrees and given a U-shape. The gaps in the places of the cuts are butt welded. The ends of the homemade profile are connected with two pieces of metal, positioned so that the valve blade passes freely between them. You should get a rectangular frame with grooves for the gate. In this case, the internal perimeter of the frame must be equal to the cross-section of the chimney.

Manufacturing of gate valves

Ready-made damper design for a round chimney

For a round chimney, the damper is made a little differently: take 2 identical metal sheets 2 mm thick, cut round holes in the center according to the diameter of the pipe, and cut out the valve plate separately.

Now the sheets need to be connected by welding on three sides around the perimeter so that the holes for the pipe coincide, and there is a gap of 4-5 mm between the top and bottom sheets. After this, all that remains is to insert the valve and secure the gate to the pipe.

Instructions for making a throttle valve

Making a butterfly valve requires more tools and time. Most often this type of damper is used for metal chimneys for modern fireplaces and metal freestanding stoves.

Set of tools for work:

Bulgarian;
drill;
pliers;
welding machine;
compass;
roulette;
marker for marking.

To make a gate, you need sheet steel up to 3 mm thick, a stainless steel pipe with an internal diameter of 6 mm, fasteners (bolts, nuts) 8 mm, and a metal rod.

First, measure the internal diameter of the chimney pipe using a compass.
According to it, draw a circle on sheet steel.
Use a grinder to cut out a circle.
Place the cut fragment into the pipe and check the tightness of the fit. If necessary, rework the valve with a grinding disc.
Place a metal tube with a diameter of 6 cm on the circle in the center and make marks on it, retreating 3 mm from each side of the circle.
Cut off the tube with a grinder.
In the resulting pipe section, drill the threads to 6.8 mm on both sides.
Drill holes in the steel circle for welding (one in the center, two 1 cm from the edge on opposite sides).
Weld the threaded tube to the steel circle.

The slide valve is ready, all that remains is to install it in the chimney pipe.

How to install?

How to properly install a valve on a stove and how to install a valve on a chimney? It's simple, let's consider 2 cases.

Installing the damper in the furnace

When installing the damper in the furnace, you need to take into account that this is done during brick laying. It is placed at the beginning of the pipe, about a meter from the surface of the furnace itself. The frame fits tightly into the chimney structure, and the damper is installed after.

Installing a valve in a furnace can be done in three steps:

Reach the 6th row of brick laying.
Apply the solution in the desired location and carefully install the frame there. Sometimes you need to cut grooves in the brick for convenience and easier retraction.
Align the frame so that it lines up with the bricks. Then you can continue laying bricks.

All cracks that may form when installing the plug must be sealed with mortar. Otherwise, there will be loss of thrust and combustion.

Video instruction:

Pipe installation

The damper is also installed at a height of 1 meter from the firebox. It is important that this is the uninsulated part of the pipe. Then there will be no temperature difference when the valve operates.

Installation on the pipe is also simple. First, the first part of the pipe is attached. The joints are lubricated with sealant (temperature-resistant). A gate is tightly placed on top of the structure (the first nozzle). The second part of the pipe is attached to the gate on top. This entire structure is connected to an insulated chimney.

Thus, there is no need to further secure the structure.

It is worth saying that homemade gates can be attached to the pipe a little differently. This already depends on the design. An example of installation of a homemade rotary gate, we reviewed the manufacturing instructions above:

We make a mark on the chimney pipe.
Let's try on our preparation.
We insert the gate into the pipe and screw it into the structure with a thread.

Tips for choosing a gate valve

It must be remembered that the correct selection of an element such as a slide damper is reflected in the future not only on the draft indicator, but also on the safety of the heating system, of which the chimney is a part. Installation of the damper is carried out on any model of fireplaces and stoves, except for the most modern ones, which have a deflector.

The main recommendations for choosing slide valves for smoke exhaust communications are as follows:

If the heating device operates by processing gas, it is better to purchase a rotary valve model. This is due to the fact that such models exclude the possibility of completely blocking the smoke exhaust channel. Thus, the heating system will be safer. The chimney, which removes combustion products from the gas stove, must be closed by at least 40 percent during operation;
There are heating systems that operate intermittently (periodic). A closed damper installed in such a heating structure, as a rule, allows steam to pass during supply, and an open damper contributes to the formation of a large amount of soot on the pipe, which is located below the plate;
It is strictly not recommended to use rotating elements for installation in sauna chimneys.

A rotating device is the most suitable option for a gas-consuming system

Note! The chimney damper is a shaped part of the chimney service, so if you purchase everything necessary for laying a chimney, it will be included with the pipes. Such shutters can be purchased at any specialized store or ordered using an online store on the Internet.

Experts recommend carefully measuring the cross-section of the smoke exhaust duct before purchasing a gate product. Perhaps this is the main thing that needs to be done before purchasing a gate.

Selecting a location option

There are several ways to install a gate, each of which has both pros and cons. An important factor is what the chimney is made of. But modern masters prefer to use the three most common options:

Installation in a fireplace insert.
Fastening using the “pipe in pipe” method.
Installation in a ventilation system.

The damper can be installed in the ventilation system. If the master has chosen the “pipe-to-pipe” installation type, he will not need to use special fasteners to securely fix the damper with the fireplace elements.
The location of the damper in the ventilation system completely eliminates the possibility of overheating of the fan motor during active operation. Modern manufacturers offer ready-to-install chimneys that are equipped with all the necessary devices (the slide damper is no exception). In this case, the part must be used in strict accordance with the recommendations established by the manufacturer. Otherwise, you can make a chimney damper with your own hands and at a more affordable price.

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There are three main options for placing the damper in the chimney:

pipe-to-pipe fastening;
placement in a fireplace insert;
installation in a ventilation pipe.

Brick chimney with damper

If you place a gate valve in the outlet pipe or in the furnace firebox, that is, build this element into its design, the damper is placed on a section of pipe as close as possible to the heating boiler. This guarantees ease of control and ease of turning the valve. This is explained by the fact that the handle will not touch either the portal or the cladding area. If it is located according to the “pipe to pipe” option, no additional fastenings are required for connection with other elements of the furnace.

Typically, ready-to-install chimneys are offered, which are equipped with everything necessary, including a slide valve. In this case, it is placed in the system in accordance with the manufacturer's instructions. If it is not provided for one reason or another, it is quite possible to manufacture and install this element yourself.

Installation features

When installing the gate at the stage of laying brickwork, the frame is placed at a height of 6-8 rows from the base of the pipe;
The frame should stand straight, without blocking the outline of the chimney;
In stainless steel chimneys, the valve is installed using the “pipe-to-pipe” technology. It is necessary to coordinate its dimensions with the diameter of the channel;
An important nuance - the damper is installed on an uninsulated section of the chimney;
The height from the firebox to the damper should not exceed 1 m (for metal channels);
Pipe height from the floor to the valve - 1.8 - maximum 2 m (for brick);
The damper in the grooves should move freely;

Gate maintenance

The gate, made of stainless steel, is usually polished to perfect smoothness. Soot settles on it poorly, but still settles. Therefore, it must be cleaned periodically.

The horizontal valve can be cleaned simply by pulling it out to the maximum and applying a special solution. Rotary - cleaned through the chimney with a special plastic brush. You should also ensure that the damper moves freely along the guides. It is allowed to periodically lubricate them with an anti-corrosion compound.