DIY gas boiler repair

Recommendation points

• Seasonal service
• Cleaning the heat exchanger
• Cleaning the burner from carbon deposits
• Checking the flue gas duct
• Elimination of water leaks at the joints of pipelines
• Checking and fixing gas leaks
• Burner replacement
• Replacing the temperature sensor

Many malfunctions of a gas boiler can be eliminated by hand without resorting to expensive services of the gas service or no less expensive private specialists for the maintenance and adjustment of gas equipment. The only rule, about which we will immediately make a reservation, you need to understand what you are doing and for what purpose.

Seasonal service

Seasonal maintenance of a gas boiler consists in cleaning it from contamination and checking its functionality. To access the boiler elements, it is necessary to dismantle the casing or casing. To do this, we decide on the method of its fastening, for different models of boilers this can be done in different ways. Most often these are several self-tapping screws and several latches in the upper part of the casing..

Having gained access to the internal parts of the boiler, we do not remove anything else when performing seasonal maintenance. Using a soft metal brush, a toothbrush and fine-grained sandpaper, we proceed to remove carbon deposits from all parts of the boiler:

• heat exchanger;
• burners;
• igniter, if available.

We use the aforementioned tool wherever it is convenient, without particularly leaning on the brush for metal. Then blow out the collected dust with a compressor. You can use a rubber tube or a tube from a medical dropper by simply blowing into it and directing its other end into the boiler..

Important! Any work on the boiler is carried out with the gas valve closed..

Using a thin awl or a strong needle, you need to clean all the holes on the burner and igniter, and then, by cleaning them again, for example, with a toothbrush, blow again. If there are overhead sensors, the places where they fit to the parts of the boiler should be lightly cleaned with sandpaper, and then wiped with a soft woolen cloth.

The ignition and flame control electrodes are well cleaned with a woolen cloth only, without the use of cleaning agents. If there are immersion temperature sensors, it is necessary to remove them from the sleeves, select the liquid present there from the sleeve, thoroughly clean the sleeve inside using a small metal brush or a loose piece of steel cable of a suitable size. After rough cleaning, the sleeve is cleaned with a cloth wound on a screwdriver, then the sleeve is filled two-thirds with machine oil and the sensor is installed.

After completing these works, the boiler is thoroughly vacuumed. In accessible places, dust and dirt are cleaned with a damp cloth. We put the trim in place. We check the presence of draft in the chimney by attaching a sheet the size of a notebook to the chimney opening, or by letting a stream of smoke into the igniter opening, the gas valve at the lowering to the boiler must be closed.

We check the seals and possible gas leaks using the soaping method. In the presence of normal draft, a test run of the boiler is carried out, which must be filled with a coolant. In parallel with the work on cleaning the boiler, it is visually inspected for mechanical damage and coolant leaks. At this point, the seasonal service can be considered complete..

Cleaning the heat exchanger

It is produced with a solution of hydrochloric acid, purchased in the trade network and designed specifically for this purpose. Cleaning is carried out for the main heat exchangers of wall-mounted gas boilers and heat exchangers for hot water preparation. The cross-section of the channels of such heat exchangers is small, which is why they are susceptible to contamination with salt deposits..

As a rule, cleaning of the water jacket of floor-standing gas boilers is not performed. The heat exchanger must be removed for cleaning. To do this, remove the boiler casing, unscrew the supply pipes to the heat exchanger, after draining the water from the boiler.

We take out the heat exchanger from the boiler. Wear rubber gloves and use a plastic container to collect the used acid. The method is not complicated. Carefully pour the acid solution inside the heat exchanger until it is completely filled. In the event that the heat exchanger is clogged with limescale, active foam will be released. Leave the heat exchanger for 10-15 minutes.

We drain the spent acid into a container and refill the heat exchanger with a new portion. We are waiting for the same ten minutes. We drain the solution and rinse the heat exchanger with running water. We put on a piece of hose on the nearest water tap and spill the heat exchanger with water. Let’s fill the heat exchanger with acid solution again. If there is no active foam generation, and when the heat exchanger is spilled with water, no significant resistance to the flow is visible, then the heat exchanger is flushed and you can reinstall it in the reverse order..

Cleaning the burner from carbon deposits

The method of cleaning the burner from carbon deposits has already been described above. However, with strong soot, it is not always possible to cope with using only mechanical cleaning. For such cases, special chemicals are used. It makes no sense to recommend anything, all tools are quite effective. The method of cleaning is reduced to applying the agent in the form of a solution to the surface to be cleaned, holding it for a certain time and then removing the exfoliated carbon deposits, usually mechanically. In more detail, you must familiarize yourself with the cleaning method by one or another tool when purchasing it..

In especially difficult cases, for example, when a heat carrier gets on the burner, it must be completely removed from the boiler, immersed in a cleaning solution for several hours. Then remove the burner, ignite in the flame of a portable gas burner. After another application of the solution, using a metal brush or a brush, remove the carbon residues.

Checking the flue gas duct

The flue gas duct is checked using a mirror. We introduce the mirror into the channel at a slight angle. In the mirror, we should see a light at the end of the chimney. When performing this operation, it is convenient to use the so-called selfie stick, with a mirror attached to it..

Elimination of water leaks at the joints of pipelines

To eliminate the leak, it is necessary to unpack the connection, clean the threads from old tow and paint. Then, using FUM tape, sealing thread or thread lock, seal the connection again. Check the quality of work by filling the pipeline and the boiler with water.

Checking and fixing gas leaks

All accessible gas leaks must be washed with a soap solution or a special gas leak checker. A solution for soaping is prepared from laundry soap by shaving it into a container with warm water and stirring until a thick foam is obtained. If gas leaks, a soap bubble will blow out on the foam. The leak can be repaired in the same way as water leak through threaded connections.

Burner replacement

Replacing the burner of a gas boiler will require more attention and care. The purchase of a new burner should be exactly the same model as the one installed on your boiler. Never install a burner not designed for your boiler model.

The beginning is the same – we remove the boiler cover. Having gained access to the burner, we carefully inspect the tubes and sensors connected to the burner. Their location should be remembered so that when assembling a new burner you do not confuse which one to connect to..

How to remove a gas burner. 1. Fixing the burner to the combustion chamber housing. 2. Electrode igniter and flame sensor wires. 3. A branch pipe for supplying a gas-air mixture

Due to the wide variety of boiler models, it is impossible to give specific recommendations, but in any case, there will be:

• a tube for supplying gas to the burner;
• gas pressure sensor to the burner;
• gas valve.

There may be a control tube from the draft sensor or electrical connection (wires) from the same draft sensor or temperature sensor. When using a burner of the same model as yours, remembering and connecting all the wires and tubes will not be difficult..

Replacing a horn burner installed in a wood stove is even easier to cope with. We unscrew the screws of its fastening to the plate and two tubes: gas supply and gas supply to the igniter. We take out the old burner, insert a new one, fasten the tubes, tighten the burner mounting bolts.

It is not worthwhile to repair the primitive automation of such a burner, the result may lead to unsafe operation of the boiler. The most difficult thing is to replace the burner of a wall-mounted gas boiler, stuffed with electronics and a large number of sensors. But don’t panic here either, the principle is the same: it’s good to remember the location of all connections to the burner.

Trying to increase their importance, gas specialists say that such a burner should be “tied” to the boiler by flashing the electronic unit or adjusting the boiler. The burner is just iron, which cannot be adjusted in any way. The settings may require combustion as such, but this is no longer relevant to the replacement of the burner itself. If the burner is made for the model of the boiler on which it is installed, then the combustion will be correct, however, provided that no attempt was made to regulate it on the old burner.

Replacing the temperature sensor

The need to replace the temperature sensor arises when, when setting a specific temperature mode of operation, the boiler either does not comply with it, or, even worse, goes into boiling mode, which can lead to rupture of the water jacket of the boiler or its heat exchanger.

Temperature sensors, according to the method of installation in the boiler, can be overhead and submersible. Clamp-on sensors are installed on the boiler pipes with clips that press the sensor against this pipe. Replacing them is very simple. Disconnect the old one – put a new one. We put the chip (electrical contact) in place of the old.

Immersion sensors can be of two types: direct immersion and located in a well filled with oil. When replacing the first, it is necessary to drain the water from the boiler, unscrew the sensor. Pay attention to how the thread was sealed at the sensor mount. This can be simply a tapered thread, using a thread lock (adhesive), gaskets, or O-rings. Sealing with flax and other materials is not used. Using the same sealing method, install a new sensor.

When replacing the sensors installed in the sleeves, there is no need to drain the water from the boiler. After loosening the fixing nut, pull out the sensor, check for the presence of oil in the sleeve, install a new sensor, fixing it with the nut. The simplest version of such a sensor is an alcohol thermometer installed in the sleeve for visual monitoring of the temperature in the boiler..