Lemax gas boiler does not turn on: frequent breakdowns and ways to deal with them

Your Lemax gas boiler, which worked properly last season or even yesterday, does not turn on? Perhaps some problems arose before, but now it completely refuses to work? Agree, staying in the cold without heating in the house is not a bright prospect.

Most Lemax gas heating boilers have fairly simple, fully mechanical automation. This means that you can fix most problems yourself. This article will help you find and eliminate the reason why the boiler does not light up.

Let's consider both external factors that interfere with the operation of the unit and its internal breakdowns. We will provide instructions for actions in different situations, and also describe the features of electronically controlled boilers.

Non-volatile boiler does not ignite

Most owners of a Lemax gas boiler choose a mechanically controlled device that does not depend on electricity. This choice is justified, since it not only allows you to maintain heating when the lights are turned off, but also significantly reduces the number of potential breakdowns and the cost of components.

Perhaps the only weak point of such boilers is the ignition system, which is responsible for the correct and safe start of the device.

Non-volatile boilers do not display an error code indicating the reason for shutdown or impossibility of starting - you will have to look for the problem yourself

Among the reasons for the refusal to start the boiler are both external - lack of draft in the chimney, insufficient supply ventilation, gas supply problems, and internal breakdowns of the boiler. We'll look at each option in more detail below.

Reason #1 - weak traction

In non-volatile boilers, combustion products rise up the chimney naturally, due to the difference in temperature and pressure. These devices are demanding on the quality, cleanliness and correct design of the chimney.

There are several ways to check for traction:

• if the air intake comes from the room, place a sheet of paper under the boiler. If it presses against the bottom of the combustion chamber, everything is fine, there is draft;
• If there is a through window in front of the burner, place a lit match into it with the boiler off. The flame should stretch out and bend forward, deep into the combustion chamber;
• boilers with coaxial chimney or two separate pipes take in air from the street - do a test with paper or a match there.

If the draft is normal, you should look further for the cause of the problem, for example, in the connection of the draft sensor.

Lack of traction can be caused by various reasons, which determine how to solve this problem.

The accumulation of soot in the chimney can reach astonishing proportions, depending on the quality of the gas and the correct settings of the boiler

Firstly, the chimney becomes clogged over time - with soot, debris, etc. It's needed clean regularly, best of all - in the fall, before turning on the Lemax gas boiler after inactivity, do not forget that not only the vertical part of the pipe needs to be cleaned, but also its elbow coming out of the boiler.

Secondly, the gas exhaust pipe must meet the boiler requirements in terms of diameter and height. In addition, at the top there should be deflector, protecting against blowing, and partially, against blockages.

Thirdly, if the part of the chimney outside the heated room is not sufficiently insulated, a cold air plug forms in it, preventing the removal of combustion products.

And finally, draft can be hampered by soot clogging the burner and heat exchanger inside the boiler. However, you can clean them yourself only superficially, with a brush. For complete cleaning, including disconnecting and washing these units with soapy water, we recommend using our instructions.

Reason #2 - gas supply is not adjusted

Quite often, owners complain that when they try to start the Lemax boiler it flares up, but immediately turns off completely. Most often, the problem is precisely in setting the gas supply to the igniter.

If it is minimal, then when turned on, the pilot burner first flares up, and then its flame is knocked down and blown out by the main burner that turns on. The protection is triggered and the boiler completely shuts off the gas supply.

If the igniter burns well, the flame covers both the piezo ignition spark plug and the thermocouple sensor, but does not come off the burner and does not form scarlet tongues, only blue ones

Another option is possible when the flame on both the pilot and main burner is set to minimum. In this case, the wick lights up, but does not reach the gas flow from the main burner and cannot ignite it.If you take a chance and wait, the boiler may ignite with a delay and a bang when gas accumulates a little in the combustion chamber, or the automation will turn everything off earlier to avoid an explosion.

If the igniter burns too actively or the draft is excessive, the flame may break away from it and not reach the thermocouple sensor and the main burner, which also makes starting the boiler impossible.

Lemax boilers are equipped mainly with Italian automatic equipment 630 Euro SIT or 710 MiniSIT, less often – 820 NOVA SIT. On all these units, the gas supply to the burners is regulated in the same way. Do not rush to turn the screws on the left side of the machine that are not covered by the lid. Despite their availability, they are intended only for professionals - these are gas pressure measuring fittings.

To begin, remove the unit cover by unscrewing one screw on its top edge. Under it you will see only 2 screws that can be turned with a regular flat-head screwdriver, larger and smaller - they are responsible for adjusting the flame of the burners.

The black screws are needed to disassemble the automation housing and have a TORX thread, in the shape of an asterisk. This is a kind of protection against unprofessional intervention, which can be dangerous

The smaller screw is located on the far left corner of the top panel and controls the gas flow to the igniter. By twisting it, you reduce the flame until the gas stops. To make the pilot burner more active, turn this screw gradually counterclockwise to the desired result, but no more than 2 turns from the fully tightened position.

The larger screw is responsible for adjusting the minimum flame of the main burner; reducing it will help increase the efficiency of the boiler.However, do not overdo it: when igniting, the burner should turn on all at once, and not gradually, and without popping noise - otherwise it is unsafe.

On the side panel, near the gas hose connection, there is a screw for adjusting the maximum gas flow, but it is better not to touch it yourself; if necessary, ask a specialist to adjust it at the next maintenance.

Possible breakdowns and their repair

The failure of the boiler to start is not always associated with inaccurate settings or external causes, but almost always the malfunction can be corrected independently.

All boilers with SIT automation have a similar structure, it is reliable and easy to set up, almost all units are accessible to the average user

Before any repairs, turn off the boiler, let it cool completely and turn off the gas supply to the riser. Even if you only had the pilot light on, the risk of getting burned is very high.

Failure #1 - the thermocouple has failed

According to the instructions, if a boiler with SIT automation does not turn on, the problem should be looked for in the thermocouple and only in it. A thermocouple is a flame detection sensor that ensures that the gas shuts off when the burner goes out.

When igniting, you need to hold down the handle or a special button for 10 - 60 seconds just so that the thermocouple has time to warm up from the flame and fix the solenoid valve in the open position.

However, there are a number of situations when this protection system works erroneously:

• the fire does not reach the thermocouple sensor;
• the sensor is smoked, oxidized, dirty;
• the copper tube of the thermocouple has burned out or no longer conducts electrical impulses;
• The thermocouple is not screwed into the adapter well enough gas valve.

This part is not difficult to find in the boiler: it is a red copper tube, one end of which is screwed into the control unit, from below, and the other into the socket near the igniter and piezo ignition.

First of all, try to slightly tighten the nut securing it to the automatic. Poor contact may cause failure. Carefully unscrew the bottom end of the thermocouple, which is heated by the flame.

As a rule, all nuts on the panel with the pilot burner are unscrewed with a 10 mm wrench, and the panel itself is unscrewed with a Phillips screwdriver

Inspect the sensor and clean it with a thick cloth or the finest sandpaper. Screw it into place and try to start the boiler.

Did not help? Look through the window to see if the flame from the igniter reaches the tip of the thermocouple. If not, bend it by unscrewing the socket with 2 bolts, or adjust the flame of the pilot burner, as we described above.

If you have a multimeter, you can independently check the functionality of the thermocouple. To do this, you need to unscrew both ends and remove the part from the boiler. At the end that screws into the automation unit, you will see a lead tip that transfers the charge to the gas valve. Clean it until it shines.

Position the thermocouple sensor so that it is exposed to fire from a gas stove burner or dry alcohol tablet. Connect the multimeter probes to the lead tip and the copper thermocouple tube and measure the voltage. If everything is in order, look for the problem further, and if the problem is in the thermocouple, you will have to purchase a new part.

Failure #2 - traction sensor does not work correctly

A draft sensor is installed at the base of the chimney and is designed to shut off the gas supply, turning off the boiler if combustion products stop being discharged.

The draft sensor is located under the top cover of the boiler - in the part where combustion products are most concentrated before being removed into the chimney

Otherwise, the residents of the house may be poisoned by carbon monoxide, so this protection system is mandatory in all gas boilers.

In non-volatile boilers of the Lemax brand, the sensor is connected to an adapter that attaches the thermocouple to the gas valve. If its circuit opens, the solenoid valve shuts off the fuel supply and the boiler turns off.

If the design provides an overheat sensor, it is also included in this circuit. Accordingly, if the sensor is not working, starting the boiler is impossible: gas will be supplied only when the handle or special button is pressed.

The sensor itself rarely fails; problems are usually caused by poor contacts and wires. First, disconnect the contacts and clean them with a thick cloth, solvent or alcohol. Inspect the integrity of the wires and their insulation, if possible, test with a multimeter; if the conductivity is broken, replace.

Dry the cleaned contacts, insert them into place as tightly as possible, the wires can be soldered to the sensor itself. Try starting the boiler.

If the situation has not changed, try closing the contacts on the adapter to the gas valve by wrapping them with wire.

The draft sensor in Lemax boilers is connected to the adapter between the thermocouple and the gas valve, at the bottom of the automation

If this helps and the boiler starts working, it means that the problem is still in the draft sensor. Do not leave the contact closed for a long time - this threatens your safety! Replace the sensor or call a specialist.

Failure #3 - nozzle clogged

It happens that when you try to turn it on, not even the wick lights up and you can’t hear the hiss of gas, that is, nothing happens. This behavior of the boiler most likely indicates that the nozzle or pilot burner injector is clogged.

To figure out how to light the pilot burner of a Lemax gas boiler, disconnect the tube going to it from the automation unit. On the panel near the burner, the gas supply tube is the middle of 3 connections; for convenience, you can first unscrew the thermocouple.

The nozzle that supplies gas in a thin stream can be the end of this tube or a separate part. Clean the nozzle hole with a toothpick and blow through the tube, making sure that air passes through.

Remove the panel on which the tube was secured by unscrewing the 2 screws on the sides. You will see a mesh on the gas supply tube - air is drawn through it to mix with gas.

Considering that the air supply comes from below, along the floor, and pets like to bask near the boiler, this mesh can become clogged with dust and wool, which does not always fade. Blow through this mesh - just without fanaticism.

If necessary, the pilot burner can be replaced along with the panel - but it is better to entrust this to a specialist who will correctly install and configure the equipment

Reassemble everything in reverse order and try to start the boiler. A positive result should be heard immediately - this is the hissing of gas supplied to the igniter.

Failure #4 - problems with piezo ignition

Piezo ignition allows you to light the boiler without matches by pressing a button. The block under the button generates an electrical impulse, which is transmitted through the wire to the spark plug and forms a spark at its end.

The automatic ignition of Lemax boilers breaks down quite rarely, but if this happens, you need to accurately determine the location of the breakdown.To do this, disconnect the wires from the spark plug located near the igniter and try pressing the button. If a characteristic click is heard, then the electrode is faulty, but if there are no clicks, then the block is under the button.

You can try to clean the spark plug from carbon deposits by unscrewing the panel with the burner and thermocouple. If necessary, buy a new part and replace it. To remove and replace the unit with the button, it is enough to remove the cover of the automation unit.

Failure #5 - gas valve is faulty

The gas valve is responsible for supplying fuel to both burners and also shuts off the gas in emergency situations. From below, the solenoid valve is controlled by a thermocouple and a draft sensor, and from above, the pressure is regulated by a balloon-bellows thermostat.

The system is multi-component, and the part is perhaps the most important in the boiler, so it is not recommended to interfere with its operation yourself.

The electromagnetic gas valve opens either when the thermocouple is heated, or mechanically - by pressing a handle or button, depending on the boiler automation model

Having heard from a specialist about possible problems with the gas valve, do not rush to get upset: replacement may not be required. During long-term operation of the boiler, lubricant may develop and adjustment may be required.

You can get to the valve yourself by unscrewing the adapter into which the thermocouple is attached and unscrewing the valve itself. This is not easy to do - the valve is tightened very tightly to avoid leaks.

The SIT control unit can only be disassembled from above using a special screwdriver or a socket wrench TORX T-20. Before disassembling the control box, be sure to mark the position of all knobs and adjustment screws.

Electronic boiler

The Lemax line of boilers, which are connected to a 220V network, is actively expanding and now includes wall-mounted double-circuit models Prime, as well as floor Clever And Wise.

Unlike imported competitors, whose control boards often burn out due to power surges, these devices are designed to operate in Russian networks.

Wall-mounted boilers, as a rule, have a built-in circulation pump, an expansion tank and significantly more control and protection systems

However, such models can sometimes fail.

To ensure safety, the main protection systems are still mechanical:

• The thermocouple controls combustion and shuts off the gas if the burner goes out - error E1;
• the draft sensor gives a signal to shut down if combustion products are not removed - error E3;
• the membrane gas valve will shut off the fuel supply if its pressure drops below critical, or the gas is turned off in the network - error E1;
• The overheating thermostat controls the temperature of the heating circuit; if it overheats, it turns off the boiler error E2.

All these systems are designed in the same way as in mechanically controlled boilers, and their location depends on the model. Therefore, we will not re-describe the inspection and repair of each component, but the instructions for it will help you find them in your boiler.

In addition, an electronically controlled boiler will not start if it detects a malfunction of any of its boards or sensors, or their unsatisfactory readings - for example, low water pressure or a supply voltage of less than 170V.

To avoid having to go through the entire boiler, the location of the fault will be indicated by the error code and its explanation in the instructions.

To set up and repair electronic controls, it is better to contact a specialist; he can resolder, reflash or replace the board

If the boiler does not react at all to an attempt to turn on, even the screen does not light up, most likely there is a problem with the power supply. As trivial as it may seem, check whether the plug is plugged into the socket, whether the machine is raised, whether there is any light in the house at all.

A child could pull out the plug from the socket, and the machine could turn off due to a voltage drop, so do not neglect this advice.

If the power supply is normal and the boiler display does not light up, call the service department for diagnostics and repair or replacement of electronic control elements.

Conclusions and useful video on the topic

It is explained in detail and clearly why the wick on a boiler with automatic EuroSIT 630, which is equipped with many Lemax models, does not light up, is described in this video:

You can get acquainted with the Lemax boiler, which operates under electronic control, in the following review:

Now you know what to do if one day your gas boiler does not start. Stay calm and check everything step by step - and you will probably be able to restore heating in your house.

What model of Lemax gas boiler do you have installed? Did you have any problems launching it and how did you solve the problem? Tell other visitors to our site about this - join the discussion in the comments.