Switching the boiler to liquefied gas: how to correctly remodel the unit and configure automation

The gas boilers offered for sale are oriented and tuned for the processing of main gas. But what, in this case, should be the owners of private houses to which the natural blue fuel supply system is not connected? After all, living in normal civilized conditions with an existing heating system is necessary now.

Everything is extremely simple - switching the boiler to liquefied gas will allow heating the house and warming the sanitary water using a group of cylinders or a gas tank. To achieve this goal, your unit will have to be slightly redone and reconfigured to other fuel pressure parameters. We will describe in detail how this work is done.

Reasons and principles for the conversion of the boiler

From the first lines, we want to warn that the conversion of the boiler for conversion to a different type of fuel should be carried out by the master of the organization with which a contract was signed for the supply of gas and equipment maintenance.

However, any owner should know the essence and stages of the process for elementary control of the actions of invited artists. And doubts about their competence sometimes justifiably creep in. Therefore, it is better to monitor the implementation of the procedure, on which, incidentally, the security of the home and households depends.

It also happens that a representative of the gas service cannot get to a remote place. In this situation, the home master, of course, will try to do everything with his own hands. But for the result of the efforts of an inexperienced craftsman in the gas sector, he will be responsible, and the manufacturer’s guarantees are void.

By purchasing a gas boiler for domestic use, we get an apparatus configured to process the mainline fuel option. A centralized gas pipeline supplies us with a mixture of flammable gases, in which methane predominates. The main gas enters the devices with natural density and pressure equal to 21 mbar.

Liquefied gas is an exaggerated name for a mixture of propane and butane, in which either the first or second component may predominate. It may mainly contain butane with a slight admixture of propane, or vice versa, propane will prevail 99%.

The density of the liquefied mixture increases 600 times. The pressure rises not so much, but still it is higher than that of natural fuels, 30-31 mbar.

To obtain liquefied gas, the pressure of propane and butane is increased by about 600 times. This procedure provides an opportunity to reduce the volume of fuel and store it before use in a liquefied state.

The types of gases used by boilers are standardized. They are assigned codes that the manufacturer indicates in the technical documentation. So, the boiler consumption of main gas is marked with code G20. The possibility of the boiler working from a liquefied mixture with a predominance of butane is designated G30, from a mixture with a predominance of propane - G31.

In order for blue fuel to fulfill its significant responsibilities, gas enters the combustion chamber through nozzles. There, the gas is mixed with air using a burner in optimal proportions for a particular type of fuel. This means that gas must be supplied to the burner in the volume necessary for normal combustion.

Normal mixture formation is possible with nozzle diameters suitable for its implementation. How much gas, under a certain pressure, enters the combustion chamber at a specific volume of air depends on the size of the supply openings. That is why nozzles with different cross sections are installed for liquefied mixtures and for main gas.

To switch to the consumption of liquefied gas, it is not necessary to radically alter the equipment, and even more so to buy a new unit. It is only necessary to change either only nozzles or a manifold (ramp) with nozzles

Note that the nozzle cross section is determined not only by the type of gas, but also by the capacity of the boiler itself. For information, for the operation of the unit with a capacity of 10 kW, operating in the maximum operating mode, the main gas needs 1.2 m³ / h, liquefied mixture of any kind 0.86 kg / h.

The more powerful the equipment, the more fuel is required for its operation. The larger should be the size of the nozzles passing blue fuel into the combustion chamber. Their cross section is clearly calculated and strictly regulated by the manufacturer, producing for a series of boilers of a given burner capacity with nozzles of a given diameter.

During the flow of gas from the nozzle, the gas is mixed with a portion of the air it needs for a normal combustion process. Both components must be fed into the combustion chamber in clearly calibrated proportions.

So how can you switch to liquefied gas, if you didn’t initially guess to buy liquefied gas boiler? Correctly, either replace the collector with the entire set of nozzles, or only the nozzles, leaving the collector in place. The second option is not possible in all boilers.

In addition to replacing devices for supplying liquefied gas, it will also be necessary to reconfigure the burner of a gas boiler with an electronic type of control.This is necessary for the full delivery of air in the amount required for the process of uninterrupted combustion. New settings will also provide interruption of gas supply in case of a risky situation.

You will also need to install a gearbox designed to adjust the pressure of the gaseous fuel. TO gas gear You can connect one or a group of cylinders. You may need to change the gas valve if necessary.

To connect the boiler to cylinders or a gas tank, it is necessary to adjust the gearbox to the operational value of the gas pressure. Sometimes it is necessary to change the gas valve in the boiler, if it is not suitable for supplying gas under the required pressure

In any situation, before ordering an artist to translate the wall or floor gas boiler for liquefied petroleum should consult the gas service in charge of your equipment and gas supply to your facility.

They will tell you which devices should be purchased for translation. They will calculate how much the upgrade will cost you along with the payment of the master.

Baxi boiler conversion steps

In order to get a full-fledged and full-fledged idea of ​​how to remodel a boiler for working on a gas cylinder, consider an example of the translation of a wall-mounted double-circuit unit of the Baxi brand.

Nozzle replacement procedure

In most boilers with the Baxi logo, there is no need to completely change the burner, it is enough to rearrange the nozzles. To do this, they need to be purchased in advance, focusing on the power of the device and the type of gas. In this example, to switch to G31 fuel, nozzles with a diameter of 0.77 mm are needed.

The price of a set of nozzles for these boilers is approximately 2.5 thousand rubles. In the kit produced for several similar boiler models, there are 17 of them and another spring. It will be necessary to change 15 nozzles, 2 spare ones are useful in case of unsuccessful actions.

And we will act like this:

• We disconnect the volatile devices of the boiler from the power supply. We turn off the unit and turn off the taps on the pipes supplying gas and water directly to the unit.
• We remove the front panel from the boiler, then we separate the screen of the closed combustion chamber located behind it.
• We unscrew the screws holding the cover of the closed combustion chamber. It is located right behind the screen.
• We disconnect the wires of two electrodes: one from the flame control, the second from the ignition system.
• Remove the burner. In order to remove it, we unscrew the two screws holding the device with Phillips. They stand on the right and left, fix the burner on the ramp.
• We unscrew the nozzles with the help of a wrench without dismantling and removing the ramp. Do not use pliers in this case. They can deform the nozzles without much effort. The nozzles of the nozzles are thin and extremely accurate in execution, it makes no sense to spoil - they can come in handy even.
• Instead of unscrewed nozzles, we install new devices designed for the supply of liquefied gas, and connect the electrodes for the lighter and the flame control system.
• Return the burner to its regular place. Guides will “prompt” her position.

With the installation of the burner all conversion procedures are completed.It remains to assemble the previously separated parts of the unit and fix the cover, the screen with the external panel in the reverse order to that in which they were disassembled.

After the alteration, all disconnected devices and dismantled parts of the gas boiler are installed in regular places in the reverse order

But that’s not all, the most serious and delicate work ahead is tuning.

The process of setting pressure “folk remedies”

This stage is often available only to representatives of the gas service. Indeed, not every home craftsman has a manometer that recognizes pressure readings in the range from 3 to 40 mbar. Buying a meter for a one-time job is not too reasonable, it is easier to use the services of a master who has this device in its arsenal.

But domestic inventors did find a way to measure the gas pressure in the system. We also managed to pick up a device capable of correctly displaying atmospheric pressure. Do not believe it, this is a regular blood pressure monitor, which probably stocked the older generation in your family.

And it doesn’t matter if a pointer or electronic blood pressure monitor is at your disposal. Both options are fine. Most of them respond well to deviations of 3 mbar (i.e. in millibars).

The only drawback is that not all devices are equipped with an appropriate scale with mbar divisions. But there is a scale with divisions by mm of mercury, and on the Internet there are a sufficient number of programs that convert all comparable physical units.

For our own convenience, we will make a plate with the translation of units of measure, then boldly proceed to reconfigure the boiler automation to work on a liquefied gas mixture.

In order to configure the boiler to work on liquefied gas using a tonometer, a table with pressure values ​​in different units of measurement is useful

In the example proposed for consideration, the pressure at the inlet to the unit should be 37 mbar. We set the pressure limits for burner operation to 4.9 mbar to a minimum, 29.4 mbar to a maximum.

We need to first retune the pressure before entering wall mounted gas boiler. In our case, everything was calculated on the use of main gas supplied under a pressure of 27-28 mbar. Now we are adjusting the gear of the gas tank or group of cylinders for the 37 mbar we need.

We configure in the following order:

• We remove the lower fitting of the gas valve, in fact, we release the point of entry of gas into the system to adjust the dynamic pressure.
• We connect a tonometer. We simply disconnect the electronic meter from the tonometer reading system, after which we connect it with a narrow hose to the gas inlet point, and immediately turn on the pointer with a pear hose.
• We adjust the pressure to the parameters required by us, given that the device will show us mm Hg. So, we need to set 27.7 mm.

Note that the arrow version of the tonometer in this case is much more convenient. The super accuracy that the electronic system is trying to demonstrate is completely unnecessary here. In addition, the switch apparatus, working without undue "fuss", it is easier to capture tenths.

They adjust the maximum pressure of the Baksi gas boiler with the help of such a nut. By shifting it clockwise, increase the value, in the opposite direction, decrease

Next, we proceed to reconfigure the pressure of the gas entering the burner directly:

• We screw the top fitting from the gas valve. We connect a tonometer to the vacated hole.
• We start the boiler so that it works with maximum settings for the characteristics of hot water and coolant.
• We adjust the upper and lower limits for heating the coolant and sanitary water by turning the nut of their settings left and right.

We turn the tuning nut carefully around its own axis. Turn it clockwise to increase, against - to decrease. We use a screwdriver with a head.We act this way until the values ​​coincide with the translated indicators in mm of mercury 22 mm for the upper limit, 3.7 mm for the lower limit.

Tenths are determined on a scale literally “by eye”. To set 3.7 mm, we find approximately the middle between 3 and 4, then slightly shift the readings to 4. Well, you can say, and set it up.

Now we twist the fitting and collect the boiler, after which we start and check its operation. The error of the settings in the example did not exceed 1%, which is really wonderful for home execution.

Similarly, all the work on the re-equipment and reconfiguration is carried out on many double-circuit wall units. Such devices include products from Airfel, for example, the Digifel and Digifel DUO models.

Modification steps with burner change

The design of a number of boilers is arranged so that there is no point in turning the nozzles separately. For them, manufacturers produce modules designed for liquefied gas. You can easily change the burner module, for example, in the boiler Navien Deluxe (Navien Deluxe).

All work consists in replacing the manifold with nozzles with exactly the same device, but with holes of a different size. The fact that it will be factory-made is a definite plus, guaranteeing the tightness of gas pipelines. It is not necessary to doubt its further safe operation.

Re-equipment and reconfiguration works in this case are carried out as follows:

• We disconnect the unit from the power supply and turn off the tap on the gas supply pipe.
• Remove the front panel from the boiler body.
• We disconnect the electrodes connected to the ignition system.
• We dismantle the gas supply pipe located within the boiler, having previously unscrewed the 4 screws holding it.
• Remove the cover mounted on the closed combustion chamber. To do this, unscrew 11 screws.
• We remove the overheat protection sensor together with the bracket intended for it.
• We remove the collector together with the nozzles fixed to it. To remove it, unscrew the two screws located to the right and left of the device.
• We install a sealing ring on the pipe to be installed, which seals the inlet of the gas pipe. We mount the new collector in a regular place and fix it with screws.
• Microswitch, the fifth in the bottom, translate to the right. So we reconfigure the device to work from liquefied gas.

After these simple manipulations, we assemble the boiler, observing the reverse sequence. In the same way, alteration and reconfiguration of most floor gas boilers is carried out, especially if they are of a condensation type. This version of boilers is often even designed for the possibility of translation.

The following photo selection will help you familiarize yourself with the procedure for replacing the manifold with gas nozzles and setting up the boiler:

Now it remains only to change the collector and configure the gas unit to work from cylinders or a gas tank:

However, you should be aware that both of the above conversion techniques are not generally implemented with all aggregate models. There are boilers that you shouldn’t even try to convert to liquefied gas, especially long-released units.

In any case, before planning a remake and translation, you need to ask the representatives of the company that completed the first launch whether it is possible to implement such a project. It is also worth examining the passport of gas processing equipment and manufacturer's recommendations. Usually there is a reservation.

Safety recommendations

Transferring the boiler and reconfiguring it to the consumption of liquefied gas dictates the need to “reconfigure” its attitude to the device for supplying and storing blue fuel.

Be sure to remember that:

• Cylinders or gas holders, which are gas storage tanks, supplying fuel to household equipment as necessary, are periodically replenished.
• It is necessary to apply for refueling a group of cylinders or a gas tank to certified organizations that have equipment for fixing the weight of the gas in the cylinder and its actual volume in the gas tank.
• Refueling of closed gas tanks is carried out at 85% of the useful volume of the vessel. This reserve is necessary in case of thermal expansion of the fuel in order to avoid explosion.

A non-hazardous, but requiring a special relationship, situation when replenishing the supplies of liquefied blue fuel is liquid filling with a density different from the density of the previous liquid. Due to this difference, the remnants of the liquefied gas may not mix with the newly filled portion.

In the reservoir, from the difference in density, a kind of two non-connecting sectors is formed, in each of which liquefied gas circulates. However, convective heat transfer will occur at a sector boundary after a short period. After equalizing the temperatures, the densities are equalized and the liquids can mix.

Liquefied gas, like main gas, is a highly flammable, combustible liquid with a high flame propagation rate. In order to avoid catastrophic situations, the operating rules should be strictly observed and cylinders should be filled not more than 85%

Usually this process, meaning direct mixing, is accompanied by intensive evaporation of the liquefied gas. To avoid losses associated with it, mixing devices should be used during the filling process. But it is better to choose a method that eliminates the above phenomenon.

Replenishment of cylinders and gas tank with blue fuel in general is a process that requires increased attention, otherwise the problems can be very serious and even catastrophic. A significant problem is recognized by the rapid spread and evaporation of the liquefied gas mixture.

If not violated safety regulations gas consuming equipment, main methane rarely explodes. This happens only with significant leaks if the technical state of the gas in the surrounding space changes dramatically. For example, in a kitchen with obvious signs of leakage, light is switched on instead of mandatory ventilation.

When expanding in a closed vessel from external heating, liquefied gas necessarily explodes if there is not enough space left in the tank to expand it. Blue fuel burns extremely intensely. Since the gas is rapidly absorbed by the atmosphere, the combustion zone expands at high speed.

Conclusions and useful video on the topic

The following video will familiarize you with the organization of heating on liquefied gas and the procedure for transferring the boiler to its consumption:

The technical and technological essence of the transfer of the boiler to the consumption of a gas mixture in a liquefied state must be known both to independent home craftsmen and to customers of the services of gas service workers.

It should be remembered that the second option is preferable, since the gas is explosive, toxic and combustible. In addition, with third-party intervention, the equipment warranty is invalidated.