Gas reducer: description, varieties, purpose

Gas reducer: description, varieties, purpose Gas reducer: description, varieties, purpose. By no means all settlements and dacha cooperatives are connected to the centralized gas supply. Unfortunately, there are also villages and villages where gas cylinders are often used. For the safety of use, they began to use a reducer for a gas cylinder - this is a special device that helps to reduce the fuel pressure to the value required for boilers and stoves.

We offer to consider all the information on the choice of a device of the reduction type.

The information presented below will help you to purchase the optimal reducer for your conditions for installation on a gas cylinder. All types of devices and the criteria by which the best models should be selected are described in detail. For those who want to perform an independent installation, we offer step-by-step instructions. Here you will find all the rules, by observing which you can protect yourself and extend the service life of gas installations.

General rules for selecting a reducer cylinder

The stability of the gas supply system will depend on how high-quality and compatible all the components.

When choosing a gearbox, you should take into account the compliance of all parameters to your needs and the characteristics of the connected devices.


In the role of the main characteristics for the device of the gas reducer, such indicators are considered as:

  • Gas type to be used.
  • How to connect to the system.
  • Outlet pressure range.
  • Highest possible performance.

  • Operating temperature range.

Cylinders and reducers can be installed outdoors or indoors. The room where the equipment will be installed has increased requirements for air exchange with the ability to quickly ventilate the room in the event of emergency situations. The outdoor option allows you to save space inside the house, and even safer during a flammable gas leak. The pressure reducing device is designed to reduce the pressure of the gas pumped into the cylinder to the operating value that is required for the normal operation of the gas equipment.

According to the type of gas to be passed, the reducers can be divided into several types, each of which is colored in a certain color for additional identification:

  • Gas reducer: description, varieties, purpose Acetyl - white.
  • Methane - bright red.
  • Oxygen - sky blue.
  • Hydrogen - dark green.

But the color coding for gearboxes that were made outside of Russia is sometimes different.

Gearboxes, which are made for storing propane-butane mixture, are painted bright red. Devices that are designed for other gases cannot be used for liquefied carbon. The characteristics of the purchased reducer must correspond to the parameters and type of the gas cylinder, as well as the device on which it will be installed.It is also important that the optimal calibration of the output gas flow rate is set.

When the pressure goes beyond the permissible limits, the automation in modern gas devices will immediately turn off everything.

If you do not have such protection, then an emergency situation may appear. Gearboxes that can be considered potentially hazardous equipment to some extent must be certified. If you have any doubts about the factory origin of the device, ask to show you the certificate of conformity.

Standards in connection to the system

In order to connect a household gas cylinder reducer, three conventional threaded connections are required:

  • W 21.8 * 1/14 - cylindrical thread according to DIN 477 / T1, but in the territory of the Russian Federation the abbreviation SP 21 is often used.


  • G - cylindrical pipe thread, the number after the designation letter is the nominal diameter in inches.
  • M - metric thread, and the first digit after the letter is the nominal diameter, and the second is the thread pitch in mm.

But "LH" means that the left-hand thread will be used. Different connection standards are used for different types of gas cylinders, and this fact should also be taken into account when you are thinking of buying a gas reducer.

So, one of the best reducer Ture 724B from the Italian manufacturer "Gavana Grоur S. р. А" has an inlet left thread W 21.8 x 1/14 for a conventional metal cylinder. The inlet is fitted with a right internal thread.

by 0.5 inches in order to connect a bellows line without adapters.

The Ture 733 device is a little more complicated, where there is a pressure regulation function from the same manufacturer with 6 input thread options - for composite a metal cylinder, under the multi-valve of the gas holder and three more different connections. This model has 3 types of outlet threads. If the outlet or inlet thread of the reducer does not match that on the cylinder / supply valve, you will need to buy special adapters.

But try to minimize number of connections, as they increase the risk of leakage. With standard gas equipment, it will not be difficult to find a reducer with a suitable format in the connection.

Installation procedure and volume

To get started but it is necessary to install the gas supply hoses without a direct connection to the cylinder. After that, install the nut from the reducer on the valve and connect the hoses. With this method, the taps of devices that run on gas, a gas water heater, stoves must be closed.

Before connecting the gearbox, to loosen the spring, unscrew the adjustment screw until it stops.

The type of screw for adjustment in the form of a valve is more convenient than those structures that need to be tightened with screwdrivers. But you should limit the access of children to such a device. If you use ordinary flexible hoses, then for ease of work the fitting can be moistened with water.This connection is secured with a screw clamp.

The bellows-type hoses are connected to a threaded adapter, which will be screwed in instead of the fitting.

After installing the system, a headspace gas test should be performed. To do this, twist the valve for gas consumption, if any, and unscrew the adjustment screw so that the spring is weakened to the maximum. After the system is assembled, you should ensure the flow of gas from the cylinder to the reducer and turn the adjustment screw, and at the same time set the required outlet pressure. After that, coat your hand with soapy water and swipe from the cylinder to the consumption device to check for gas leaks.

If you use a gas stove as a consumption device, then you should light up the burners sequentially, and if on one of them the flame is not blue, then the pressure on the reducer should be reduced. Yellow and orange flames mean that the fuel is not fully combusted, which means that prolonged use of the stove can become dangerous. When checking the operation of the burners at minimum heat, a damping problem may appear. To solve it, either slightly increase the outlet pressure using the adjustment screw on the cylinder reducer, or change the position of the supply screw on the plate.

If the problems described above are not typical for all burners, then clean or change the jets on the problematic unit of the stove.

If a gas leak occurs during system start-up, close the shut-off valve fully. Then ventilate the room and you can start troubleshooting.

What volume and pressure is needed

Now let's talk about the pressure of the gas reducer, as well as its volume. The capacity of the reducer should help to ensure the operation of all devices connected to the system at the maximum gas consumption mode. A certain problem lies in determining the required parameters in different units of measurement.

There are two units for measuring pressure in gas appliances - pascals and bars. For a reducer, the inlet pressure is specified in megapascals or bar, and the outlet pressure in pascals / millibars. The conversion of pressure values ​​between two units can be performed using the following formula:

1 br = 10 5 Pa

The volume of gas that is passed through the reducer and consumed by gas devices can be presented in two quantities at once - in kilograms and cubic meters. Indicators of the outlet and inlet pressure of a large number of Russian devices are indicated in Pascals, and on foreign devices, the pressure is calculated in bars.

Indicators can be correlated using data on what is the density of the main gas cylinders (kg / m 3 ) at a temperature of +19 degrees and normal atmospheric pressure:

  • Gas reducer: description, varieties, purpose Carbon dioxide - 1.


  • Propane - 1.88.
  • Oxygen - 1.34.

  • Nitrogen - 1.17.
  • Helium - 0. 17
  • Argon - 1. 67.

  • Hydrogen - 0. 08.
  • Butane - 2. 41.
  • Acetylene - 1.


If you recalculate for household stove types, a problem may appear that is related to the proportion of propane and butane in the gas cylinders. Their ratio in percent for different climatic regions is regulated in accordance with GOST 20448-90. The density of the gas mixture will depend on the percentage composition, for example, with a ratio of 65% propane and 35% butane, the gas density is as follows:

Q = 1. 88 * 0.

65 + 2. 41 * 0. 35 = 2. 06 kg / m 3

So, if the maximum gas consumption on a four-burner stove is 0.85 m 3 / hour, then the transmission of the same volume must be provided by the reducer.

In terms of kg, this value will be 2.06 * 0. 85 = 1. 75 kg / hour. Based on GOST 20448-90, a large range of the percentage value of gases is allowed in a propane-butane mixture, which will create uncertainty during the calculation of its density.

To the calculated value, the maximum transmission capacity of the gearbox can be increased by 25%.

This is due to the following:

  • Gas mixture parameters may vary depending on region, supplier and even season!
  • Gas density which will be used for all calculations will depend on the temperature.
  • There is a possibility of loss of elasticity of the spring, which is responsible for adjusting the volume of the chamber with low pressure in the pressure regulator of the gas cylinder, which may reduce its maximum throughput.

Sometimes, in a set with new equipment, it is suggested to use a proven reducer with pressure control in case you use a propane cylinder. This option is optimal from the standpoint of fire safety and system performance.

Design features and maintenance

System operation without the slightest problems is simply impossible if you do not carry out regular maintenance and do not eliminate even minor gearbox faults. To do this, you should know what is the design of the device and what are the signs of typical breakdowns.

Diagram reverse and direct acting device

By the type of construction, gearboxes can be divided into direct and reverse acting devices. In the first case, pressure with excess in the form of incoming gas will be directed to open the valve, and in the second, on the contrary, there is a lack of pressure in the working chamber of the structure. The design of a single chamber reverse and direct acting gearbox is quite simple.

Due to the fact that there are no complex units, the device serves without breakdowns for a very long time (provided that the product was made with high quality).

The main elements in both types of gearbox construction do not differ:

  1. Gas reducer: description, varieties, purpose Fitting, through which gas is supplied.
  2. High pressure gauge, it shows the pressure of the gas that is supplied to the device.
  3. Reverse spring that works to close the valve.
  4. High pressure chamber.

  5. The valve, and its position, controls the amount of gas that is passed through.
  6. Safety valve that is triggered when an impermissible pressure value appears inside the cooking chamber.
  7. Low pressure gauge, helps to determine the working pressure of the gas.
  8. Working chamber with low pressure.
  9. Adjustment screw that determines the position of the diaphragm.

  10. Main spring.
  11. Membranes inside the working chamber.
  12. Pin between the check valve and the spring.

Gearboxes with reverse action have become much more common, since they are many times more reliable. There are device models with pneumatic pressure sensors, and instead of the main spring, there is a gas action on the diaphragm, which ensures the equilibrium of the system.

Typically, the adjustment screw has a tight stroke, and this is directly related to the fact that it is impossible to allow spontaneous change of position under the action of the force directed on the diaphragm. When clockwise rotation occurs, the volume of the working chamber decreases and the outlet gas pressure increases.

In standard reducers, the unevenness of the outlet pressure will depend on the value of the inlet pressure, and reach approximately 15 to 20%. Dual chamber models are used when accurate outlet gas pressure is required.

This oxygen gas reducer perfectly shows a two-stage design - it is essentially two separate devices that are connected together.

Such devices have a more complex design and are slightly more expensive and also more expensive than single-chamber counterparts. For this reason, if there is no need to use them, it is impractical.

Periodic inspection and service work

For correct and long-term operation of the gearbox, it is necessary to carry out certain procedures regularly. So, once a week, you should record the readings from the manometer, and with a decrease in the elasticity of the springs, there will be a noticeably slow but constant increase / decrease in pressure.

Every 3 months the following steps should be performed:

  • Check the tightness of the mating gaskets, pressure gauges, product body and safety valve.

    This can be done by applying soapy water to areas of potential leakage.

  • Purge the relief valve to prevent sticking. To do this, connect the reducer to a compressed air source, and then, when the outlet is closed, increase the pressure to a state where the protective mechanism is triggered.

Also, it is prohibited to carry out repair work and maintenance, that is, all operations that involve physical impact on the device body (and tightening of threaded connections) when the gearbox is under pressure. This is dangerous in that flammable gases can be released and ignited.

In addition, a sharp depressurization of the device can occur, causing physical damage to people who are in the room. Gas service specialists can conduct an annual inspection of equipment to identify non-conformities in safety and issue prescriptions with a detailed elimination algorithm.

Popular faults and repairs

Deviations and gas leaks can be eliminated without the help of specialists. The leak can be caused by the following reasons:

  • The device case has leaked.
  • Diaphragm damaged.

Gas leakage through element joints that are loose can be eliminated by replacing the liner or using silicone sealant. A damaged diaphragm should be replaced with similar elements from the repair kit.

Reasons for deviations in values ​​may be:

  • Gas reducer: description, varieties, purpose Spring - dismantle the gearbox and find the cause of the malfunction. If the spring is displaced, it should be corrected, and if it is broken, replace it. If there is a loss of elasticity, then it is enough to place a solid gasket under the spring.

  • Leakage of compressed gas in a device that has a pneumatic principle pressure on the diaphragms - this problem is difficult to eliminate on your own, and therefore it will be necessary to completely change the reducer for the gas cylinder.
  • Diaphragm problem. If for some reason a rupture occurs, then the device assembly should be replaced, and if there is a loss of tightness at the junction with the washer, eliminate such a malfunction by tightening the edge.
  • Problem with the bypass valve - If the rubber gasket is worn out, then it just needs to be changed, and if the rocker arm does not move, replace the hinges.

Taking into account the average cost of gearboxes, it will be more expedient to repair them only when it is not possible to replace the entire gearbox.

If it was necessary to do a parsing, then for safety reasons at the first start, be sure to check its tightness.


The selection of a reducer for a gas system should be carried out taking into account the parameters of pressure and throughput volume that you need. Timely elimination of minor faults and simple maintenance will make it possible to perform all functions for a long time and well.