Currently natural gas is the most optimal fuel for heating a home. The only negative is that it is not always possible to connect the heating system to the main gas pipeline. In this case, you can pay attention to an alternative in the form of liquefied gas - boilers using bottled gas are not uncommon in our country.
Classification
Boilers operating on liquefied gas are single-circuit and double-circuit. A single-circuit boiler is intended only for heating, while a double-circuit boiler is capable of both heating a house and providing hot water supply.
Consumers are offered wall, floor gas boilers with open and closed cameras combustion. In addition, you should pay attention to the power of this heating device. The variety of modifications often makes it difficult for the user to choose, so it’s worth taking a closer look at the most important characteristics.
For boilers operating on liquefied gas, the ability to operate at low pressure is fundamentally important.
A constant supply of bottled gas will be carried out at a pressure of 3-4 Mbar. Therefore, when selecting a boiler, you should pay attention to this parameter.
Efficiency
Efficiency is one of the most important parameters heating system. Liquefied gas is more expensive than main gas, and transportation costs must be added to its cost.
The efficiency of modern, working equipment can reach 90-95%. To calculate gas consumption for heating, you need to know the total area of the room: approximately 1 kW of power is consumed per 10 sq.m.
For heating and water heating in country house 100 sq.m. will require about 2 cylinders per week and 8-9 cylinders per month. You can connect cylinders into a group: according to the rules, the use of a cylinder system of up to 15 pieces is allowed. In this case, gas containers must be kept closed. metal cabinet.
Installation equipment
To install the heating system you will need:
- a gas boiler;
- burner for liquefied (cylinder) gas and the gas cylinders themselves;
- shut-off valves and gearboxes.
Burners for bottled gas differ in their configuration from conventional ones, and are usually included in the standard configuration of gas boilers. If necessary, they can be purchased separately. Shut-off valves and the necessary gearboxes can be purchased from the company or directly at cylinder refill stations.
Connection
A cylinder or group of cylinders is connected to the boiler through a reducer with a throughput capacity of about 2 m3 / hour. Gearboxes for home stoves are designed for lower throughput - they are not suitable for a heating system. The gas tank system may have one common gearbox or a separate regulator for each cylinder. The second option is more expensive, but this is what the experts recommend - separate gearboxes provide maximum safety.
Liquefied gas cylinders cannot be installed outdoors: the cold will cause a decrease in pressure, and the heating pad may refuse to work. Ideal place for installation is a warm, ventilated room. It is important to remember that bottled gas is heavier than air, and if it leaks, it will pool at the bottom, increasing the likelihood of an explosion. Therefore, the premises should be chosen separately from living rooms. There should be no basements or subfloors in it!
Gas cylinders are connected to the boiler burner using a metal corrugated pipe - this reduces the likelihood of gas leaks due to system vibrations.
Using automatic sensors and correct settings you can reduce propane consumption rates by 3-4 times. If we're talking about O country house, then gas consumption will be even lower: during the period of absence of people, the automation will maintain the temperature at 6-9 ° C, which will reduce propane consumption to 0.7-0.8 cylinders per week. Heating a building with liquefied gas is not the cheapest option, but in some cases it is the most optimal if there is no problem with the delivery of cylinders.
The gas boiler performs its functions perfectly even when connected to the main gas pipeline. In this case, it is quite easy to switch the equipment to a constant source of fuel supply - just change the burner.
But if there are no prospects for connecting the building to the gas pipeline, you should once again calculate the feasibility of installing gas boiler. For home with total area more than 100 m2 and maintaining a temperature of about 25 ° C, it is worth considering the possibility of installing a solid fuel boiler or another heat generator and water heating.
Refueling
Cylinders undergo mandatory certification once every 3 years - this is necessary for own safety user. Such containers can serve for about 10 years. Standard house consumes about 10-12 cylinders per month, so they will have to be refilled weekly - you cannot transport more than 3 cylinders at a time without special permission.
Before filling, the vessels need to be prepared. To do this, you need to remove condensation, which artificially reduces the useful volume and harms the steel walls. Removing condensate is the prerogative of specialists; doing such work yourself is always a risk. If for some reason it is difficult to find a specialist, you will have to carry out the procedure yourself. The cylinder is taken to open space without sources of fire, ground and then remove the gearbox. Leave for 2 hours to allow any remaining gas to evaporate. After two hours of inactivity, the vessel turns over and the water flows into the ground. You can take it to a gas station.
It is worth choosing a gas station that organizes both transportation and a guarantee for the work. It is better not to contact car stations, because their equipment does not have a special cut-off valve that regulates the filling of household gas cylinders. They also do not have a special connector for connecting the cylinder to station equipment.
CONNECTING THE BURNER TO
GAS cylinder
1. Hold the burner control valve and apply
it to the thread of the cylinder and screw the cylinder tightly against
clockwise. Tighten it only by hand and
Be careful not to damage the threads.
2. Always keep gas cylinder in direct
vertical position, connecting it to the burner.
Drawing
3. Make sure that the burner and cylinder are stable
stood on the ground without the risk of turning over.
4. Leave enough free space around
burners - at least 1.25 m on each side and 1.5 m
above.
5. Always install a windbreak in front of
how to light the burner (see section 3 “Using
burners for cooking").
ATTENTION
Risk of fire or serious injury from
gas leaks.
Never light the burner if you notice a sound.
hissing or smell of gas after connecting
cylinder to the burner. The gas contains impurities with unpleasant
smell. Never use a burner that
smells like gas.
Do not use the burner if it is damaged or
faulty.
When connecting a gas cylinder to the burner, never
don't twist it too tightly. It may
damage the burner or cylinder and cause leakage
fuel.
Be careful when using the burner
negative temperature. In the cold, sealing
The rings may harden and begin to leak fuel.
(cm. " General rules security").
It is unlikely that at least one modern person can imagine his life without a stove. But there are situations when gasification of a home is impractical or impossible. The reasons are different, but the result is the same: people have to use liquefied propane in cylinders. When equipping a point yourself, many questions may arise, from choosing a location for the device to connecting to an energy source. Mistakes and errors made during the installation and connection of the gas stove to the cylinder can lead to irreversible tragic consequences.
Important! Gas equipment that will be used for cooking must be in good condition.
Materials and tools required for work
When connecting a gas cylinder to the stove you will need:
- 2 clamps;
- a fitting having a spout for attaching a hose and internal thread(must be included with the gas appliance);
- the stove is new or old, but in good condition;
- reducer with inlet pressure 30 mbar;
- gas cylinder made of metal-composite, polymer-composite or other special materials with a capacity of 5–50 liters;
- rubber or rubber-polymer connecting hose that can support room temperature and does not heat above 30 degrees;
- sealing tape;
- special gas key.
Important! To connect the gas model of the stove, you must use only keys with brass or copper plated, which will not produce a spark upon impact.
Jets for bottled gas
- . Purchased at specialized sales points, it must be intended specifically for gas. Its length must exceed the distance between the connected equipment by 150 cm, since it is prohibited to use it in a tense state.
Important! Do not use old hoses, as the integrity of their internal surface may be damaged.
Choosing a place to install the cylinder
Before connecting the gas stove to the cylinder, you need to choose the place where the devices will be installed, since the distance between them must be at least 100 cm. Safety instructions require that there be a window in the room with connected gas equipment.
When using a shielded cylinder, the distance between it and the stove can be reduced to 50 cm.
- If the gas container will be in the same room as the kitchen appliance, it is advisable to place it in a metal cabinet or make a wooden mount.
- The cylinder may be located in the pantry located behind the kitchen wall. In this case, you will need to make a hole for the hose.
- The best option in terms of safety is to install the cylinder in a special metal box located outside and locked with a padlock.
Important! You can place a cylinder in an apartment only if the building has no more than 2 floors.
The use of bottled gas requires a thorough approach to ensuring safety and ease of use. We suggest you consider simplest example connecting a propane tank to gas stove: connection diagram, shut-off and control valves, organization of storage conditions.
Where to install the cylinder
The main general requirement for the use of gas equipment can be called ensuring the safety of people. For this reason, gas cylinders are not recommended for installation in habitable rooms and technical rooms connected to a residential building directly or through ventilation.
A distinctive feature of propane gas is its high density. Bottled gas heavier than air and can accumulate in the lower floors of buildings. Therefore, it is strictly forbidden to install cylinders in underground or technical rooms below ground level. If in normal cases small leaks do not pose a danger due to constant air exchange, then in the lowlands gas can for a long time accumulate to explosive concentrations. Gas cylinders can only be installed in accordance with SNIP 42-01-2002 inside buildings no higher than 2 floors, in quantities of no more than one and at a distance of 0.5 m from gas stoves and 1 m from heating devices.
To make the installation safer and prevent access to gas equipment by unauthorized persons, the cylinders are placed either in a room with a separate entrance or in an outdoor metal cabinet. Particularly important when outdoor installation consider temperature regime operation. Bottled gas is a mixture of propane and butane, each of which has a different boiling point. When the cylinder is cooled below 0 °C, only propane will evaporate from the mixture, while the remaining butane in the cylinder cannot be efficiently used. With more low temperatures it is possible to completely stop the flow of gas to the stove.
The main way to achieve normal operation at low temperatures is the use of so-called winter gas mixtures, capable of evaporating at temperatures down to -40 ° C. However, the problem is that such gas may be in seasonal shortage, and the possibility of filling with a mixture of mediocre quality cannot be ruled out. There are two ways to resolve the warranty issue: either insulate the attached metal cabinet, relying on heat penetration from the building, or additionally heat the cylinders using a self-regulating cable.
The height of the cabinet should be at least 20-30 cm greater than the height of the cylinders, so that they are not installed on the floor, but with a gap, for example, on two metal slats or a high pallet. In this case, the cabinet must be protected from the penetration of melt and rain water and heating from sunlight above 40 ° C.
Which gearbox to choose?
Gas stoves have built-in jets designed for constant pressure gas, while the pressure in the cylinder decreases as it flows. To normalize combustion, the cylinder is connected to the stove not directly, but through a reducer. Gearboxes for liquefied household gas are called propane and, as a rule, have a red or metallic body color.
The main characteristics of the gearbox are outlet pressure and throughput- must be selected according to the parameters of a particular slab. If it is not possible to set the nominal pressure value, you should purchase an adjustable type reducer and set it manually. Also, adjustable reducers are directly indicated when using cylinders with a capacity of 20 liters or more, where the pressure drop is more pronounced.
Reducers are recommended for the use of propane for domestic purposes. reverse principle actions. Due to the low pressure values of liquefied gas and the low difference at the inlet and outlet, the use of multi-stage gearboxes is economically unjustified. The only requirement is to use reducers provided for by their technical standard in conjunction with composite cylinders.
A separate nuance in choosing a reducer may be the temperature regime of the cylinders’ operation. The fact is that when liquid gas evaporates, an intense decrease in its temperature is observed. So, if initially the propane-butane mixture is at a temperature of -5...-10 °C, in the reducer itself its temperature can drop to the condensation mark, due to which the gas becomes liquid again and the reducer stops working. One way out of this specific situation is to use gearboxes with a built-in heating system.
What hoses and tubes to use for connections
According to the rules for the safe operation of gas equipment, oxygen and hydraulic hoses are not allowed to be used for laying gas pipelines. This is due to the high temperature difference between the transported gas and external environment, which leads to accelerated degradation of the hose material and the appearance of microscopic leaks. Given the properties of liquefied gas to accumulate in rooms, such phenomena pose an increased danger.
There are three options for connecting a gas cylinder to a stove. The first is to use special flexible rubber hoses for flammable hydrocarbons. In this case, their connection to the gearbox is made through a standard fitting reinforced with a screw clamp. The same fitting is installed on the inlet pipe of the gas stove, the hose is connected to it also with a clamp. If it is necessary to connect two sections of hose, the use of double-sided fittings is not allowed; instead, threaded connectors with double crimping of the shank with clamps should be used. Distinctive feature Such connections for gas pipelines are tapered threads and lack elastic seals.
Connecting the plate to the cylinder using flexible hoses has a number of limitations. The length of the hose should not exceed 150 cm, its gasket must remain visible to constantly monitor the condition of the sheath and avoid damage. Some of the prohibitions can be partially circumvented by using metal bellows hoses. They form a semi-rigid structure, which can have an almost unlimited extent, while maintaining resistance to temperature influences and mechanical damage.
At the same time, safety rules prohibit the passage of flexible and semi-flexible ducts through walls, where their condition cannot be assessed visually. If it is necessary to connect a kitchen stove with a cylinder installed outdoors, the hole in the wall should be at cement mortar a case made of steel pipe. Inside the case there is a steel tube of smaller diameter with threads at both ends, the space between the walls is filled with a plastic sealant, for example, polyurethane foam or silicone. Connection of bellows or flexible hoses must only be made through threaded adapters of the appropriate type.
Cranes and other fittings
At the point where the gas pipeline is connected to the stove, a gas tap, blocking the gas supply in the event of a malfunction of the stove. This can be either a ball valve with a yellow handwheel or a gas plug valve. The disadvantage of the latter is the need for periodic maintenance.
Another useful addition to a gas pipeline can be a flow meter. Its inclusion in the transportation chain will help to respond in a timely manner to the depletion of the mixture in the cylinder and replace it. The metering device does not have to have the outstanding accuracy necessary to monitor gas consumption in main networks; a device costing up to 2 thousand rubles will be sufficient.
When connecting several cylinders at the same time, a connecting ramp can be used. Its installation helps reduce the rate of gas evaporation from each cylinder and makes the risk of freezing the mixture in the reducer less likely. Installation of the ramp can be done independently using any gas pipeline material.
Modification of the slab for bottled gas
Not every stove can initially run on liquefied gas. The main obstacle is higher operating pressure, due to which there is a lack of oxygen in the burners, which results in yellow color combustion and the appearance of soot.
The situation can be corrected by replacing the methane nozzles with nozzles for LPG. They have exactly the same form factor, but the hole diameter is slightly smaller. If you plan to connect a new stove, it will most likely come with a set of liquefied gas nozzles. If there are no replacement jets, they can be purchased at a reasonable price.
The diameter of the holes in the liquefied gas nozzles depends on the pressure in the outgoing chamber of the reducer and the power of the burner. So, standard values for liquefied gas stoves, diameters are considered to be 0.43-0.6 mm for a pressure of 50 mbar and 0.5-0.75 for a pressure of 30 mbar. Individual cooker manufacturers may set their own diameters, and the use of nozzles with different hole diameters may void the warranty.
Replacing jets can be done in two ways, depending on the design of the plate. In the simplest version, it is enough to remove the burner body and look inside the seat sleeve. If a nozzle is visible at the bottom - a hexagonal head with a hole in the center - unscrew it with a 7 or 8 mm socket wrench and screw in the nozzle to replace it. If a cone with a hole is visible inside, you will have to remove the top panel by unscrewing several bolts on the sides from different sides. The nozzle itself in this design option cannot be unscrewed; it is pressed onto the stuffing box seals. You need to unclench your mustache crimp coupling, move the nozzle down along with the supply tube, and then remove the nozzle from the landing fitting and install a new one.
Commissioning of the plant
The entire installation of the gas pipeline is carried out without connecting it to the cylinder. When the tubes or hoses are connected to the stove and interconnected, the reducer nut is screwed onto the cylinder valve and tightened. Then, if a flexible hose is used, it is put on the fitting and crimped with a clamp. If bellows tubes are selected, the fitting must be unscrewed from the gearbox housing and a threaded adapter of the appropriate size must be screwed into it.
When the installation is assembled, you need to open the valve on the cylinder and, by rotating the reducer regulator, set the required outlet pressure. When the gas has entered the system of tubes and hoses, each connection is thickly coated with foam soap solution and checked for leaks. Once the integrity of the gas pipeline has been confirmed, you can open the stove tap and try to ignite the burners sequentially.
If each of them smokes or the flame burns in a color other than blue or greenish, it is necessary to reduce the pressure using the valve on the reducer. If the malfunction is typical only for some burners, it means that the jets for them are selected incorrectly. If the burner goes out in the minimum fire position, adjust the low flow screw on the stove tap or try to slightly increase the pressure with the reducer screw.
Absence gas pipe in a private house turned into headache for residents of Russia. Many settlements still not gasified. And supplying a pipe to the site where a residential building is located costs from 150 to 300 thousand rubles. Not everyone can afford such an amount. Installing a gas cylinder will help solve the problem. Despite the fact that refilling and replacing it requires attention and caution, this task is accessible to everyone.
Gas cylinder for the dacha: advantages and disadvantages
When a person enters a private house, which is not connected to the gas pipeline, he is faced with a choice: use an electric stove, or is it possible to connect a gas stove to a cylinder? Both solutions have both advantages and disadvantages. The benefits are as follows:
- A gas burner heats up much faster. Cooking time is shorter, which means more free time.
- The cost of refueling is lower than the price of electricity. The exception is the use of electricity at a reduced rate. For example, for village residents. There is also a discount on payment utilities to the poor population.
- In some regions, the rate of electricity consumption per person is limited to 50 kW per month. Once the limit is reached, the price increases significantly.
The disadvantages include:
- Fare. Gas stations are less common than gasoline ones.
- Inability to accurately determine how much fuel was filled into the cylinder.
- Installing a gas stove in a room not equipped with ventilation is prohibited.
Where to place
First you need to decide where to install the tank. If you connect a gas cylinder to the stove in the country, you can place it in the kitchen not far from the stove. However, in the house for permanent residence it's better to place it in separate room or outside in a metal cabinet. It's more secure.
If gas is stored at temperatures below 0 °C, then the propane-butane mixture must be winter-grade, otherwise it will not be completely consumed. Another advantage of installing cylinders on the street will be the absence of gas in residential premises (in case of a possible leak).
They are also not allowed to be installed in an unventilated area or below ground level (for example, in a basement or cellar). Propane is heavier than air, so it will pool if there is a leak. At a ratio to air of 2.3 to 9.5%, propane forms an explosive mixture. The distance from the gas cylinder to the kitchen stove should not be less than 1 m. And also not less than 1 meter to the heating appliances.
Installation diagram
To connect a permanent structure and country house applies different scheme. cylinder to the stove in a residential building? In this case, it is more rational to have a supply of several cylinders stored in a steel cabinet. It installs on concrete foundation with a base 0.25 m above ground level. The distance from the cabinet to the wall of the building should be 0.45 m, from the slab to the pipe passing through the wall - at least 0.2 m.
Cabinets with cylinders must not be placed on the side of the building façade, or on the side of transport passages.
Gas supply for summer kitchen
To connect a gas cylinder to a stove in the country, use the following diagram:
All detachable connections must be within reach to monitor their condition and check for leaks. Spare cylinders are prohibited from being kept in a residential area, even for a short period of time. According to safety regulations, they cannot block escape routes.
What are there
There are several options for gas delivery standard sizes containers. For frequent use, it is better to choose a tank big size. Whereas a gas cylinder for the dacha can be taken in a smaller size. It is more convenient to transport and easier to find a place in limited space. The cylinders have the following characteristics:
Please note that the volume of propane poured is less than the volume of the container itself. This is due to the safety of the gas cylinder. Tucked in winter time gas expands significantly in a warm room and can rupture the cylinder if filled in excess.
Rules of circulation
To protect yourself from the consequences associated with damage to the cylinder, you need to understand the operating rules:
- Conduct scheduled certification. It consists of conducting a leak test under pressure and maintenance valve After that, a stamp is stamped on the upper skirt of the gas cylinder indicating the date of inspection and the expiration date of the certification. In addition, gas stations refuse to fill containers that have not passed inspection.
- Private individuals are prohibited from transporting more than 5 cylinders at a time.
- If defects in the housing or leakage through the valve are detected, the container must be sent for repair and maintenance.
- Do not allow overheating under direct sun rays.
- During transportation, the valve must be closed with a protective cap.
- Do not completely bleed gas from the tank. Sometimes this can lead to air being sucked in and forming an explosive mixture.
The operating gas pressure is 1.6 MPa. During periodic testing of the container, the pressure is raised to 3 MPa. For safe work the proportion of propane in the propane-butane mixture must be at least 60%
Difference in slabs
Kitchen stoves, sold in stores, use natural gas - methane - for combustion. The nozzle, which is located inside the burner, is designed to operate on this type of fuel. If such a stove is correctly connected to a gas cylinder, as many try to do, it will not work effectively. The flame will not create desired temperature and will smoke. This happens because the propane-butane mixture is in a liquefied state, while methane is in a gaseous state under pressure. More liquefied gas flows per unit of time, so the jets must be smaller. Therefore, before connecting the gas cylinder to the stove, the nozzles should be replaced. They come complete with the stove.
To change them, you need to remove the top surface of the kitchen appliance. To do this, remove the burners. Then release the side clamps and remove the top cover of the stove.
Changing the nozzle in the oven is also not difficult. To do this you need to remove back wall oven, after which access to the interior of the oven will open. The nozzle is connected to a gas supply tube, which is fixed with a metal bracket on the body. There is a rubber gasket between the tube and the nozzle, which must be installed when replacing the nozzle. It is very small and may not be noticed. It must be removed carefully so as not to damage it.
How long will one bottle last?
The 50 liter capacity is enough for several months of regular use. Cooking for a family of 3-4 people will use up gas within 3 months. If you regularly close the gas valve, the cylinder will last for a longer period. It is difficult to determine how much gas was added during refueling. Even a pressure gauge connected to the cylinder will only show pressure. You can accurately determine the amount by weighing the container before and after refilling. Knowing the density of liquefied gas, you can understand how much was filled. To avoid deception associated with underfilling, you need to refuel at proven gas stations that have meters.
Camping gas stoves
Fans of long-distance travel often take with them travel stoves, on which they can quickly cook or heat up food. These are miniature devices weighing no more than 2.5 kg, easily fitting into a backpack or bag. The power of the burners of these devices is comparable to the power of the burners of household stoves - about 2.5 kW.
Their difference lies not only in their low weight, but also in the fact that they use gas in aerosol cans, which weigh from 200 to 500 g. Tourist stoves are equipped with wind protection for the burner. Expensive models have closed ceramic burners, which protect people from burns and protect the fire from bad weather.
How to connect a camping gas stove to a cylinder? The portable device has an adapter with a lock. You need to carefully insert the nozzle of the can into this adapter, lightly press on it and, aligning the grooves, turn it. When you press, you will hear a slight hissing sound, indicating that the valve has opened and gas is entering the device. After fixing the canister, you need to listen carefully. If the hissing does not stop, it means there is some kind of imbalance in the installation. You need to disconnect and do the operation again.
How to connect large format gas cylinders to a portable stove? To do this, some devices include a propane hose and a miniature reducer. The 5-liter cylinder does not take up much space and can be taken with you on a car trip.
Two in one
In order to reduce the number of calls to gas stations and reduce transportation costs for gas delivery, you can connect several cylinders into a single system. Such a connection is called a ramp. How to connect two gas cylinders to a stove? To do this, you need to add several devices to the connection diagram:
In this way, you can connect as many cylinders as you like. Such schemes are also used for heating houses.
How to connect a cylinder to a stove with your own hands
For self-connection you need to choose the right gas fittings:
- Hoses. They must be designed for a propane mixture and can withstand operating pressure. They need to be checked for cracks. If the cylinder is installed outdoors, then it is more advisable to install a pipe from the gas source into the room.
- Gas reducer for propane for domestic use. It differs from the industrial one in its narrow range of pressure adjustment, the absence of a pressure gauge and its low price. Its capacity is 1.2 cubic meters. m/hour. On one side it has a nut for connecting to the cylinder, on the other there is a fitting for the hose.
- Clamps for fixing hoses to the fitting.
In addition, you will need a gas wrench and a screwdriver to tighten the clamps. When changing cylinders, be sure to monitor the condition of the gasket under the gearbox nut. Its malfunction will lead to excessive fuel consumption. Can be installed as a gasket top part plastic bottle cap, making a hole in the center and cutting to the desired diameter.
How to avoid accidents
Usage gas equipment refers to dangerous species activities. To prevent trouble, you must follow several rules:
- Do not leave the burners on for long periods of time unattended, especially at night.
- Do not place cookware on burners without grates.
- You cannot bring fully filled cylinders from a cold place into a warm room. Expanded gas can rupture the container.
- Do not illuminate the meter with a lit match when checking.
- Do not tie ropes to clothes drying pipes.
- Do not allow young children to turn the stove on and off.
After connecting the gas cylinder to the stove, you need to check the system for leaks. Connections may leak gas. To ensure serviceability, you need to treat the connections of the hoses with the valve, reducer, or stove fitting with a soapy solution. If bubbles appear, the leak must be repaired.
The connection between the cylinder and the reducer must be checked after each refueling. Over time, non-volatile residues accumulate inside the container, and the useful volume of the reservoir decreases. Therefore, the condensate must be drained periodically. Fittings and nuts must be brass or bronze. Unlike steel ones, they do not produce a spark if accidentally struck.
The coupling nut on the propane reducer has a left-hand thread. This must be taken into account and unscrew it clockwise. Otherwise, the thread may be stripped.