Imagine being excited to spend a cold winter’s evening inside your home, only to discover that your gas boiler has vanished out of nowhere. Many homeowners have experienced this annoying situation at some point. But do not worry; we are here to explain why this occurs as well as how you can troubleshoot and resolve the problem on your own.
First, let’s examine the possible causes of your gas boiler suddenly ceasing to function. A frequent offender is a shortage of fuel. This could be caused by problems like an empty gas tank if you’re using a propane system, a closed gas valve, or even an interruption in the gas supply. Your boiler can’t operate properly without a sufficient supply of fuel.
Your gas boiler may also malfunction due to an issue with the ignition system. It may have trouble lighting the gas, which could result in a shutdown, if the pilot light or ignition electrode is broken or dirty. In a similar vein, a broken flame sensor or thermocouple may trigger the boiler to cut off as a safety precaution against gas leaks or other dangers.
The crucial part is here: learn how to resolve these problems and restart your gas boiler on your own, without the need for professional assistance. Make sure the gas valve is open before proceeding if you suspect a fuel supply issue. Make sure your propane tank isn’t empty if you have one. Check the gas line for any leaks or obstructions that might be preventing fuel from flowing.
To address problems with ignition, start by cautiously relighting the pilot light in accordance with the manufacturer’s instructions. If you have an electronic ignition system or the pilot light won’t stay lit, make sure the ignition electrode is properly aligned and cleaned. Likewise, as these parts are essential for identifying the presence of a flame, clean or replace the thermocouple or flame sensor as needed.
Always keep in mind that when troubleshooting your gas boiler, safety comes first. To prevent mishaps or injuries, make sure to cut off the boiler’s gas and power supplies before attempting any repairs. Don’t be afraid to ask an experienced HVAC technician for help if you have any questions about any step of the troubleshooting procedure or if the problem still doesn’t go away after trying various solutions.
You can ensure that your home stays comfortably heated throughout the winter months while saving time and money by learning the common causes of gas boiler failure and how to resolve these issues yourself. Any problems relating to boilers that you encounter can be resolved with a little perseverance and knowledge on your part.
Common Reasons | Solutions |
1. Pilot light out | Relight pilot light following manufacturer"s instructions. |
2. Gas supply issue | Check gas valve, ensure it"s open; if closed, open it. If still not working, contact gas provider. |
3. Faulty thermocouple | Replace thermocouple, usually located near pilot light. |
4. Air in gas line | Bleed air from gas line by turning off boiler, then slowly reopening gas valve. |
5. Blocked flue | Clean flue to remove any obstructions. |
6. Low water pressure | Check pressure gauge on boiler; if low, refill system to recommended pressure. |
Our article "Why the gas boiler goes out and how to fix it yourself" delves into the problem that many homeowners encounter: a gas boiler that shuts off unexpectedly. We dissect the potential causes of this annoying issue, ranging from thermostat malfunctions to pilot light problems. Our intention is to provide readers with easy do-it-yourself fixes for their heating systems so they can restore functionality without having to pay for costly expert assistance. Homeowners can address this inconvenience and make sure their homes remain warm and comfortable throughout the winter months by following our step-by-step instructions, which include lighting the pilot light again, checking the thermostat, and troubleshooting common issues.
- Why does the burner of a gas boiler go out?
- Extinguishing of boilers with an open combustion chamber
- Problems with draught
- Reducing the gas pressure in the mains
- Shortage and excess of air
- Malfunctions of the atmospheric boiler
- Repair of wall-mounted and turbo units
- Video on the topic
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Why does the burner of a gas boiler go out?
The solution is straightforward: every heating unit that uses natural or liquefied gas has dependable automation installed on it that cuts off the fuel supply. Any of the following three scenarios will result in burner shutdown and gas boiler fading:
- Reduced or lost traction in the chimney;
- gas pressure in the supply line has fallen below normal;
- The flame of the burner itself has gone out.
As a point of reference. The gas valves used in the automatic shut-off devices are either American-made Honeywell or Italian-made EuroSIT models.
Automation can function in response to the influence of outside variables as well as when any component of the heat generator breaks down. Because there is essentially nothing to break down in non-independent floor standing boilers and because external causes rather than malfunctions are more frequently responsible for the burner extinguishing, these boilers are easier to maintain. These brands include Ross, Danko, Zhitomir, Aton, and other gas appliance producers from the former Soviet Union.
A more contemporary wall-mounted electric gas boiler with a closed combustion chamber is like a mini boiler room with extra safety features that cut off the fuel supply in certain circumstances.
- stopped the movement of coolant in the heating system (the flow sensor is triggered);
- air supply has decreased or stopped, which is signaled by the pressostat (another sensor);
- In the house power grid there are voltage spikes;
- in case of power failure.
Note: Currently, only one Russian manufacturer, Neva, sells high-quality wall-mounted boilers; imported brands from Korea and Europe make up the majority of the market.
It is difficult to adjust the wall-mounted heat generator when it starts to malfunction, but there are a few issues that can be fixed by hand. Read on to learn how to do it correctly.
Extinguishing of boilers with an open combustion chamber
By default, we take into account the scenario in which the heating system has operated for several seasons without experiencing any issues, but has recently started to malfunction. The following is a longer list of causes for the automatic valve to cut off the gas supply:
- the draft in the chimney has disappeared;
- there are problems with the natural gas supply, causing its pressure in the pipe to drop below normal;
- the boiler does not have enough air for combustion, causing the flame to go out;
- the burner is blown out by a strong wind outside or the flame breaks off in a strong draft inside the house;
- hardware faults of the gas boiler – failure of the draught sensor or thermocouple.
A poetic aside. Particularly if the unit is placed in a different room, the homeowners may not immediately notice the gas burner device fading. When the private home’s air temperature has already dropped, the issue is discovered.
Therefore, if the boiler’s main burner goes out, check the chimney for drafts first before looking for other possible causes. Let’s examine each step in greater detail.
Problems with draught
Checking the draught is the first thing atmospheric gas boiler owners should do when the burner goes out. Light a candle or a box of matches, carry it over to the viewing window, and watch how the flame behaves. The draught is OK and you can move on to the next step if it is deflected towards the opening.
There is no draught in the chimney, and the fire stays put because the reason why the burner died has been identified. How to proceed:
- Open a window in the boiler room to ensure airflow into the room.
- Disconnect the section of the chimney connected to the heater outlet, then check for draft in the chimney itself. If it is, it is necessary to disassemble and clean the gas boiler itself, which is described in a separate article.
- If no draft is detected in the main duct, it is probably clogged. Find the maintenance and cleaning hatch, it is located in the boiler room below the connection point or outside. Open the hatch and slip a mirror inside to see the exit hole. If it can"t be seen, then the chimney needs to be cleaned.
- Inspect the chimney cap from the outside, a bird"s nest may have appeared there during the summer period. Another option – solid frosting of the cap covering the cut of the flue pipe. This happens in case of severe frosts, when ice blocks the working cross-section of the chimney.
Crucial! Umbrellas on top of chimney pipes are expressly forbidden by the operating regulations of gas-fired appliances. You have to take that hood off if you have one. You can only use open tapered nozzles.
Let’s recap the reasons behind clogged chimney channels:
- uninsulated brick walls are destroyed by condensate, which causes the passage section to be clogged with construction debris;
- in cheap sandwich chimneys from the inner wall can peel off the zinc coating and as a thin film block the channel;
- 2 boilers are connected to one chimney – gas and solid fuel, so it is clogged with soot;
- foreign objects from bird activity can get into the chimney.
When it’s cold outside and the chimney’s walls are frozen through, cleaning the chimney could not work. The truth is that the gas heat generators’ combustion products only reach a temperature of 120 °C, which is too low to heat the chimney and produce a steady draught. Since you won’t be doing insulation in the dead of winter, your only option is to purchase a can of disposable burner, light it, and place it in the cleaning manhole that is open. Start the boiler as soon as the frozen channel begins to warm up; do not leave it running for an extended period of time as this will require repeating the process.
Details to ponder. When a neighboring property builds a two- or three-story cottage next to your house, certain situations arise. Because of this, the chimney may end up in the lee of a nearby building. This reduces the draft, which causes the gas boiler to go out. You will need to raise the chimney by one to two meters in order to remove it from the stagnant zone because you are unable to stop your neighbors from building.
The simplest and least expensive solution to wind blowing into a malfunctioning chimney is to install a damper on the gas boiler’s output. It is true that its location will need to be adjusted when the weather changes. This is because the heater won’t operate at its best when a portion of the channel is partially closed, which could allow carbon monoxide to enter the house. Thus, raising the chimney by one or two meters is the most effective way to prevent draught overturning.
Reducing the gas pressure in the mains
Checking the fuel supply is the next step to take after you are certain there is a draft in the chimney. The burner going out suddenly but the boiler’s igniter flame staying lit is an indication of low gas pressure at the inlet. What is actionable:
- Check how well the gas flows from the pipe. First close the door to the boiler room, open the window and unscrew the supply hose from the pipe of the heat generator. Briefly open the gas tap. The sign of a good supply is a loud hissing from the hose and a strong odor of odorized methane. Put the hose in place and check the tightness of the joint with soapy water.
- If the fuel arrives badly, clean the gas strainer, then try to ignite the wick and the main burner of the boiler. If the result is negative, call the appropriate service and call a master gas engineer.
Take note! Make sure you use the shutoff valve to turn off the gas before tampering with the fuel line!
Another location the main line may clog en route to your heating unit is inside the gas meter. This occurs when rust or scale from welding gets into external pipelines after they have been repaired. However, disassembling the metering device for cleaning is not permitted; in this case, only contacting a master will be helpful.
When thermal equipment is turned on in private homes in large quantities at the start of the heating season, the fuel supplier is required to keep an eye on mains pressure and increase gas supply volume. There may not be enough fuel for customers who are at a dead end in the network when the service responds slowly at times. All you can do is call the supplier’s company in a furious manner or, if you have one, turn on a second boiler that runs on wood or electricity.
Shortage and excess of air
Any of these occurrences increases the risk of the gas boiler catching fire on occasion. The furnace room needs fresh air from other rooms or from a ventilation duct in order to function normally. While operating in low power mode, avoid allowing strong drafts that could blow out the burner.
Checking for oxygen deficiency is simple: just open the closest window and watch how the flame behaves. The cause of the fading is obvious if the burner’s operation has stabilized. Let’s examine the reasons behind this:
- you have installed airtight plastic windows and the air flow inside the house has stopped;
- One or more interior doors have been replaced and the gaps between the sashes and the floor, where air used to pass through, have been greatly reduced;
- you have put a powerful kitchen hood, pulling part of the air flow on itself;
- The same effect is observed when installing a forced extractor hood in the toilet and bathroom.
When purchasing different exhaust devices, keep in mind that the air removed must be balanced by the air entering the system; otherwise, the chimney’s draught will lessen or possibly tilt in the other direction. The issue of what to do if the wind blows the gas boiler will then come up. Special air inlets must be installed on plastic windows, and a mechanical inflow from the street must be set up to offset forced exhaust.
A supply unit’s purchase and installation are not inexpensive. Organizing natural inflow to areas that are overheated (like the kitchen or the boiler room directly) can be a compromise, as the outside air will have time to warm up.
Gas boilers and convectors on a separate story with a short coaxial chimney that passes through the wall outside. If the flue outlet is located in an unfavorable location, it is not uncommon for the burner to be blown by the wind because combustion products move along them naturally. Finding the direction of the yard’s draught and shutting the protective grate on the windward side will solve the issue.
Malfunctions of the atmospheric boiler
Several components in non-volatile floor heat generators eventually give way after years of operation. These are the telltale signs of their breakdown:
- When trying to ignite the igniter, it goes out immediately after releasing the button on the valve. This means that the thermocouple, which is heated by the wick and keeps the gas solenoid valve open, has failed.
- Floor standing gas boiler does not ignite at all, not even the ignition burner. This indicates an unreliable contact in the electrical circuit connecting the automation unit with the draught sensor. The element itself rarely fails.
- When the main burner ignites with difficulty, works with interruptions and pops, and the color of the flame is yellow, then the main fuel jaculator is clogged.
A bimetallic element is attached to one end of a copper tube to form the thermocouple. From the second side emerges a capillary that is attached to the gas valve. The igniter flame washes the junction of dissimilar metals, producing a voltage of 20–50 millivolts that keeps the valve solenoid open. The thermocouple can only be replaced; it cannot be repaired.
A brief explanation of the working principle. We manually open the valve during ignition, and a thermocouple holds it in place once the wick heats up. Traction sensor installed in series with the solenoid to break the circuit in the event that the smokebox’s accumulated gases overheat.
The draught sensor is a pill-shaped component that is attached to the gas valve via two wires and is situated at the combustion product outlet. Checking the operability is simple: just close the contacts where these wires are connected, try lighting the burner, and replace the sensor if it works. Old connecting wires that create a high resistance can occasionally be the source of the malfunction because the boiler is only supplied with a negligible voltage. You can either replace them or clean every contact to resolve the problem.
It is not advised to use your hands to remove the boiler’s gas burner device in order to clean the jaculator. If there’s no other choice, though, remember to turn off the gas before beginning any work, and then remove the fasteners. Avoid disassembling the gas main’s unnecessary joints, and after assembly, use a soap solution to ensure that they are tight.
Addendum. When the circulation pump outside the boiler breaks, the floor heating unit’s burner won’t light up. After heating the water in the boiler tank, it will turn off and wait for the heat transfer fluid to cool.
Repair of wall-mounted and turbo units
Gas boilers that are wall-mounted and have both an open and closed combustion chamber are more sophisticated appliances that come with contemporary safety features and electronics. But some issues can still be resolved on their own in this situation. The checks on the fuel supply, sensors, and draught that were previously discussed apply equally to atmospheric heat generators that are wall-mounted.
You should equip yourself with a Phillips screwdriver and the product instruction manual in order to identify any problems with the wall-mounted electric gas boiler. You probably won’t need any other tools. The heater display’s fault codes are explained in the technical passport, and removing the front panel requires a screwdriver.
The heat generator is in three non-operational states:
- The boiler is completely switched off, no indicator light is on.
- The unit is switched on, the display and the mains indicator light are on, but the automatic ignition does not take place.
- There are attempts to start the main burner, but after ignition it immediately extinguishes.
Advice: Always make sure the wall-mounted boiler is powered on in case of a total failure when it’s connected to the main power supply. One of the distribution board’s circuit breakers may have tripped, which would be the root of the issue. Second moment: nearly all imported units are phase location sensitive, and this can be resolved by simply rotating the plug in the socket so that the contacts alternate positions.
After confirming that the heater is receiving voltage, we can move on to fixing condition #1. To accomplish this, use a screwdriver or key "under the star" to unscrew the gas boiler’s front panel, then remove it or tilt the front cover (depending on the model). The following is an additional algorithm:
- Locate the fuse box and check each fuse with a multimeter or visually. There will probably be one burned out one.
- The spare fuse is usually glued from the inside to the front panel. Put it in place of the burned out one or buy a new one (of exactly the same nominal value)!).
- Try to start the heating unit. If it works, the repair is over, put the cover back on.
- The appliance starts up and then "dies" again? The only thing left is to call a master, because the problem is more serious.
Advice: After prying open the panel, thoroughly examine every component of the heat generator to check for burned-out parts on the board, broken or missing wires, and leaky joints. In the event that the latter is found, contact a technician right away. Our expert Vladimir Sukhorukov will explain more in his video about the wall-mounted gas boiler’s troubleshooting algorithm:
The display indicates an error code for the other two malfunctions, which you can use to find the issue by consulting the product data sheet. The specialist suggests doing the following: You should contact the service provider if the documentation opposite the error code indicates to do so because you are unable to handle the breakdown on your own. You can get rid of these mistakes by yourself:
- Clogged strainer filtering the coolant from the heating system. Disconnect the heat generator from the house power supply, turn off the taps and clean the element"s mesh.
- The built-in circulation pump does not work. Causes – rotor jamming or air blockage. In both cases, unscrew the large screw (stands in the center of the pump) and bleed the air or turn the rotor with a screwdriver. Proceed carefully, a little water will come out of the hole.
- When the boiler pressure gauge shows low pressure, and there are no leaks in the heating system, you need to pump air into the expansion tank, mounted inside the heating unit. The pressure on the air side of the diaphragm should be 0 less than the pressure on the air side of the diaphragm.2 Bar than in the system. Read more about pumping the tank here.
- If a leak is detected at low pressure, it must be repaired and then add water to the system.
Note: If the room thermostat’s electrical circuit or the gas boiler’s internal thermostat is damaged, the display won’t indicate a problem. Further details from our expert are provided in the second segment of the video:
The efficiency with which your gas boiler operates during the winter months is crucial to maintaining a warm and comfortable home. On the other hand, problems such as the boiler cutting off without warning can be annoying and inconvenient. You can save time and money if you know why this occurs and how to fix the issue on your own.
A common cause of a gas boiler turning off frequently is an inadequate supply of fuel entering the system. Problems like low gas pressure, a clogged fuel line, or a broken pilot light could be the cause of this. Make sure your boiler is off before beginning any troubleshooting, and follow safety precautions to avoid mishaps or additional damage.
To begin with, make sure your gas meter is operating properly and that there are no problems with the supply if you think there might be a problem with gas pressure. Next, look for any leaks or obstructions in the fuel line that might be keeping gas from getting to the boiler. Fixing leaks and clearing any debris will usually take care of the problem and keep your boiler from cutting off without warning.
A broken pilot light is another possible cause of a gas boiler cutting out. This tiny flame is what ignites the gas and maintains the boiler’s operation. The pilot light may need to be cleaned, replaced, or moved if it keeps going out. For information on how to access and maintain the pilot light safely, consult the owner’s manual for your boiler.
Sometimes a malfunctioning thermostat or overheating can cause a gas boiler to shut off. It is imperative to promptly address any unusual sounds or smells coming from your boiler, as well as any rapid cycling on and off, in order to prevent further damage. Examine the thermostat for indications of harm or inaccurate settings, and contemplate adjusting or swapping it out if required.
Many common boiler problems can be fixed with simple maintenance and troubleshooting, but some may require professional assistance. Understanding the parts of your boiler and adhering to safety precautions will help you identify problems early on and fix them, keeping your house toasty and cozy during the heating season.