Why does the gas boiler produce soot?

Causes of soot formation in the boiler

As a result of combustion, under certain conditions, a product of incomplete combustion. soot is formed on the walls of the boiler or chimney. Often it is called ammonium carbon because of the lack of crystal structure. Soot occurs in several cases:

In order for the boiler to function properly, it is necessary to raise the temperature in the furnace as much as possible, namely to exclude its cooling by the stove or other probable ways. You can also make chamotte grate in the top of the firebox, which will act as a heat reflector. You can judge how well the fuel burns by the smoke emitted: if the smoke is black or dark gray, it means that the fuel does not burn well enough. The lighter the smoke, the better the fuel burns.

To solve the oxygen problem, it is necessary to create the draught necessary for combustion. In boilers with natural draught, the combustion chamber of the open type allows to perform this action independently, and in boilers with forced draught there is no need to regulate the oxygen independently due to the fan performing this function.

Combustion in the boiler of plastic bottles, plastic bags, plywood, chipboard and items containing plastics and rubber will not only lead to increased soot formation, but also the likelihood of an unpleasant odor in the room.

In order to minimize the amount of soot in the boiler and chimney, connoisseurs recommend to heat dry aspen firewood and dried potato peels.

Professionals recommend cleaning the chimney at least once a year. If cleaning is carried out less frequently, there is a possibility of a large layer of soot and, consequently, a decrease in the operation of the boiler.

does, boiler, soot


The snap (mini-explosion) when igniting

The boiler is 5 months old, first winter, but recently noticed that the ignition. the furnace cracks, the gas is heard clearly, sometimes fine. Sometimes it feels like the boiler is going to burst. that it can be? I did not notice this during the winter, only when it was getting warmer outside, by the way, I noticed that this usually happens when the boiler is 33-37 degrees (up to 40 degrees).I took the lid off the combustion chamber wiped the burners with a toothbrush, the piezo with a rag. Seems to be a little better, less frequent, but it still pops

Classification of malfunctions

All problems with gas boilers can be divided into categories:

  • Primary or secondary. Primary are indicative of problems of indicative nature in functioning of one or even several units. If the failure has not been eliminated, there is a secondary malfunction. It is the result of ignoring the problem. After a secondary malfunction occurs, the equipment stops working.
  • Hidden or obvious. The first group includes leaking heat exchangers or joints, breakdowns in the hot water or heating circuits, as well as other malfunctions that can not be identified by a person without adequate training.
  • Gradual or sudden. Some faults develop unnoticed due to the changed parameters of the units operation or the changed conditions, whereas others are unpredictable and appear suddenly in the least convenient moment.
  • Final damage. Sometimes the cause of the failure can be immediately identified. For example, after dropping the unit immediately stops working. In this case the cause is mechanical damage.

Burner fading

Among the most common malfunctions is the burner fading. If this happens during the start-up of the appliance, the cause is considered to be:

The first reaction to burner extinction should be to check the draught. This is very easy to do. light a match or a candle and then bring the flame closer to the air duct. The presence of a stable draught is indicated by the tip of the flame, which is directed inside the boiler body. The fire should not go out. If there is no draft, the tip will deflect slightly. Sometimes the draft is too high. Then the flame will rush into the air duct, start swinging violently or go out altogether.

Another common cause of burner extinction is the thermocouple, or rather insufficient contact. In this case when starting the boiler the burner ignites, but the flame goes out quickly, making a soft popping noise. You can fix this kind of problem yourself. To restore operation you just need to clean the contacts.

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Methods to normalize draught

If the burner goes out immediately after ignition, the cause may be in the draft sensor. This problem cannot be solved by restarting the equipment, because the sensor is a supervisory component that blocks the unit.

To diagnose a breakdown of this part, simply close the terminals, bypass the sensor and then start the equipment. If the boiler normally turns on and continues to work as usual. the sensor is out of order. It can be replaced by your own efforts. If the unit does not start, then you should immediately shut off the gas and call a specialist. Only a master can conduct a proper diagnosis of the boiler, using specialized devices. It should carry out an inspection of the main and auxiliary elements when diagnosing the equipment.

Excessive draft can provoke blockage of the unit, the air mass tears off the flame, causing the gas supply to be cut off. The strength of the draft can be determined without turning off the equipment, because when it is abundant, the flame acquires a light yellow color, instead of blue, or becomes colorless. In addition, if there is a strong draft, the appliance operates with a constant hum.

The cause of the problem draft can be improper placement of the chimney or boiler. Strong gusts of wind can disrupt the free flow of air, there is excess pressure, the chimney can be clogged. As a result, the flame goes out and the boiler is blocked. To avoid this happening, it is worth trusting the installation of heating equipment, as well as arrangement of the chimney professionals. They take into account in their work not only the current rules and standards, but also the direction of the wind, as well as many other features.

Reasons of reverse thrust

Back draft. one of the possible reasons why the boiler smokes when opening the door. It has already been mentioned above. If combustible products are not removed through the chimney, but go into the living room, it is worth analyzing the cause of this situation and urgently begin troubleshooting. As a rule, the exhaust gas sensor built into all modern brands of units also reacts in this case.

does, boiler, soot

For all that, the solid fuel boiler smokes a lot when you open the door, contaminates the window on the door. The cause is usually the same. All gases circulate from a high pressure area to a lower pressure area. Natural draught appears when the chimney is at an optimum height.

To check if there is a reverse draft, you can bring a lit match to the chimney. In the case of natural draught, the fire will deflect in the direction of the boiler, but if the reverse thrust. from the boiler.

The most common cause of back draft is weather. A gust of wind gets inside the chimney and prevents harmful waste from escaping. Similarly, when the outside temperature drops. Sometimes it is simply necessary to wait until the pipe becomes warmer, and the natural circulation of combustion products will adjust.

It is also possible that the design and type of chimney flue selected incorrectly. There may be damage. The chimney should have as few bends as possible for unobstructed smoke extraction. Diameter and type of chimney selected for each boiler based on its type and power parameters.

Reasons of bad chimney draught

To begin with, it is necessary to understand why there is a poor draft in the furnace. Problems can arise from the beginning and in the process of operation. The following are the most common causes:

  • Chimney clogging (soot on the walls or any fallen debris from the street).
  • Errors at the stage of construction (a large number of branches and horizontal sections leads to an increase in pressure losses along the length of the channel; in addition, the pipe should be the same diameter along its entire length for uniform speed, which determines the formation of soot stagnation).
  • Leaky joints of the pipeline (it can occur both at the stage of construction, and over time, so it is necessary to periodically check the quality of the channel).
  • Wind support (often it is because of the wind there is a temporary overturning of the draft, so it is desirable to choose the place for installation of the chimney very carefully).
  • Improperly chosen diameter of the channel in relation to the capacity of the stove.
  • Lack of supply air.

Causes of reverse draught

To control the cleanliness of the chimney, on the vertical part of the chimney below you can mount a piece of pipe with a plug, removing it periodically, you can get rid of most of the accumulated garbage.

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Chimney design

Important! The top of the chimney may get into the zone of wind back pressure, this possibility must be considered when choosing the location of the pipe on the roof.

Location of the chimney on the roof of the building is very important for the correct operation of the stove. Previously mentioned in this article, the height of the chimney must be at least 500 mm. But these are only general guidelines for a flat roof, in fact, the height of the chimney depends on the distance to the ridge and the height of the surrounding buildings. Here are a few basic rules for the height of the chimney:

oil burner making black soot

  • If the distance to the ridge of the building is less than 1.5 meters. the height of the chimney must also be at least 0.5 meters.
  • If the chimney is located at a distance of 1.5 to 3 meters from the ridge. it is made no lower than the ridge, regardless of height.
  • If the chimney is more than three meters from the ridge. it must be no lower than a line drawn from the ridge at an angle of 10 degrees to the horizon.
  • If taller buildings are attached. the pipe must be led above them.
  • If next to the chimneys are exhaust ducts. the height of the hood should be taken at least the height of these pipes.

Chimney installation option

Important! According to the requirements of SNIP, steel piping can only be used when the temperature of the air transported is less than 500℃. In coal furnaces the use of metal pipes is prohibited!

Violation of ventilation

On the ventilation is worth more detail. While most people know or guess about the other problems, ventilation is usually forgotten. Often problems arise because of the second floor in the bathhouse, for example, when the emission of combustion products is located too close to the second floor windows. Encountered air currents create excessive pressure, which interferes with normal draft.

Ventilation ducts in the chimney

One often forgets about the ventilation in the boiler room itself. There are plastic windows everywhere, which are very hermetic and do not let the outside air in at all. If they are closed and there are no air inlets, then when the stove burns, after a certain period of time there will be a critical vacuum in the room, and small streams of air will periodically rush in through the pipe. This phenomenon is extremely unpleasant and it is necessary to take care of sufficient ventilation in advance. In some cases, natural ventilation is not enough and you want to install a fan, because with the mechanical stimulation of air exchange is active and the lack of oxygen will not be.

does, boiler, soot

External factors

If the chimney is not used for a long time (in summer, for example), birds can make nests in the chimney or hornets can build a hive. This phenomenon is very common, so it is important every time before the heating season to check the chimney. When visually inspecting the inside of the chimney, you can also find a large amount of soot buildup, which creates additional resistance. Unfortunately, chimney ducts are not eternal, and over time they can deteriorate, which should also be checked periodically.

Checking and cleaning chimney ducts

Changes in weather conditions, such as fog, rain, or strong gusts of wind are often the cause of reduced draft. Swirling of air flows near the outlet of the chimney creates additional resistance. Such phenomena not only reduce the draught, but can also cause it to tip over.

Why the boiler is smoking?

The house a year ago installed a gas water heater, until recently, there were no reproaches. While cleaning the tube coil noticed a build up of soot. Why the boiler is smoking? What would cause a similar?

Probably the reason that the boiler started smoking was the turbine stopping or the chimney lost draft. Excessive air as well as a lack of air can affect the operation of the boiler. The draught regulator must be checked. Another permissible cause could be fouling of the atomizers or a disturbance of the turbulence. Fuel supply malfunction is also one of the causes of soot.

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Causes of soot formation in the boiler. Chimney.

Causes of soot formation in the boiler. The chimney.

Why is there soot and tar in the boiler?? The main reasons why a large amount of tar settles on the walls of the boiler can be two, it is condensation, which leads to the formation of tar and poor draft. Today we will consider how the draft affects the work of solid fuel boiler.

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If the chimney draft in a solid fuel boiler is bad, it can affect:. When you open the boiler door (toss the fuel), the smoke will go through the least resistance and you get a quick smoke of the boiler room huge settling of tar on the walls of the boiler, it can even flow out of the bottom door when dirty the walls of the boiler reduces heat transfer, increases fuel consumption contamination of the chimney, the possibility of ignition.

What are the causes of poor chimney draught? The most important is to fulfill the conditions specified in the certificate of the boiler. If it is specified that your boiler diameter should be 200 mm, it must be at least 200 mm, narrowing is NOT desirable, increase is not desirable. Below are pictures of the chimney where the diameter was narrowed, which led to the formation of tar not only in the boiler, but also in the chimney itself.

does, boiler, soot

black soot from boiler & other issues

After 3 months of operation the chimney was dismantled and replaced with a chimney of the correct diameter. After replacing the tar on the walls of the boiler burned out and the operation of the boiler normalized. We remind you that the narrowing of the chimney is unacceptable.

Number of turns should not exceed 3, the turns are made at an angle of 45 degrees, or 2 turns of 90 degrees. Horizontal extension should not be more than 1 meter.

When installing the chimney, the structure of the roof and the location of nearby structures must be taken into account.

Only observance of strict rules will allow you to get comfort when using heating equipment and use it for the entire operating period without failures and malfunctions.

How to get rid of leaks?

The appearance of condensation in the chimney associated with certain laws of physics and get rid of it completely will not. The same applies to soot and tar in the flue gases. some amount of these substances will inevitably settle on the walls of the chimney. Dirty black streams in the chimney appear precisely because jets of condensed water capture particles of soot and tar and roll down the chimney.

If the boiler is set up correctly and operated at full capacity, then despite the ubiquitous condensate, there will be no dirty leaks. The fact that productive combustion of fuel will not only lead to the burning of almost all the tar in the flue gases, but also to the effective drying of the flue.

As a result, the sweat of condensed water will cease to collect on the way soot and will simply dry up without a trace in a short period of time. Only one question remains. How to use the boiler at full power, if you want to maximize its combustion and to prevent overheating of water in the system?

To solve this and many other issues that arise when designing a heating system, a device called a heat accumulator has been developed. The heat accumulator (TA) is a special water tank of 250 to 3000 liters capacity, which acts as a heat energy accumulator.

No matter how hot the boiler is, it never overheats if the system has a thermal accumulator. The buffer tank with a large amount of water will absorb all the excess energy. And the accumulated reserve will be gradually consumed after all the fuel in the boiler burns out and the unit stops heating water to the desired temperature. Energy reserve of a properly designed TA can be enough for 4-5 hours of full heating operation even in the coldest winter months.

Based on all of the above, the most correct approach to solving the problem with dirty sweat on the chimney is to operate the boiler at full power. In addition to getting rid of this problem, this rational use of the heating unit will give the maximum performance of the entire heating system. In turn, the only acceptable option for continuous operation of the boiler at full power is to install a heat accumulator.

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