Malfunctions of Daewoo gas boilers: decoding error codes + repair recommendations

A breakdown of any element of the heating system usually completely stops the heating process of the house.The most problematic place in the circuit is the boiler, which consists of many components. The complexity of the design makes repairing it a difficult task.

However, not everything is so bad, since malfunctions of Daewoo gas boilers, for example, can be determined almost instantly thanks to a flawlessly functioning display system. Of course, not all problems can be fixed on your own, but in some cases you can do without the services of gas workers.

You will find everything about deciphering error codes that arise during the operation of Korean equipment in the article we presented. We will tell you how to react to data from the self-diagnosis system. We'll tell you how to quickly solve the problem and restore heating in full.

Daewoo gas boiler series

Daewoo is one of the most famous Korean conglomerates, which ceased to exist in 1999. Many divisions of the concern gained independence or merged into the structure of other companies.

Now in South Korea there are two companies that were previously related to the corporation and produce gas boilers:

• Altoen Daewoo Co., Ltd (until 2017 - Daewoo Gasboiler Co., Ltd). Now production facilities are located in Dongtan.
• Daewoo Electronics Co., which produces gas equipment at the factories of the KD Navien company.

Components for boilers from both companies are manufactured in South Korea and Japan, and assembly is carried out automatically.

Altoen Daewoo Co., Ltd did not transfer production facilities to Chinese industrial clusters so as not to lose the opportunity to constantly monitor the quality of products

The following lines of gas boilers from Altoen Daewoo Co. are presented in Russia. Ltd:

• DGB MCF. Boilers with an open combustion chamber.
• DGB MSC. Boilers with a closed combustion chamber.
• DGB MES. Condensing type boilers with a closed combustion chamber. Models in this line have a weekly operation programmer, an autonomous control panel, and simplified chimney connection.

All models of the listed lines are wall-mounted, double-circuit, that is, designed for heating and hot water supply.

Models of the DGB series are equipped with an informative display that displays an error code if a problem occurs or the built-in automatic diagnostic system is triggered

Daewoo Electronics Co. There are two lines of gas boilers: wall-mounted “DWB” and floor-mounted “KDB”. They have their own characteristics, including error codes that differ from competitor models. However, these boilers are not widely used in Russia.

Therefore, this article will only provide error codes for gas boilers from Altoen Daewoo Co., Ltd.

Errors and methods for eliminating them

The number of automatically detected faults in Daewoo boilers is grouped into 19 events, each of which has its own code. Seeing the display, you can try to solve the problem yourself or give called technicians a first idea of ​​the problem that has arisen.

Some malfunctions of gas boilers do not depend on the type of combustion chamber or other features of the equipment. And there are problems that are typical only for a certain line. Daewoo Altoen (Gasboiler) boilers have continuous numbering of errors, and the methods for eliminating them are almost the same for all models.

Error type "E0"

This code indicates an error in the room temperature sensor, which is built into the control panel. The example of this malfunction shows that it is not every time that you need to call a repair team.

It is necessary to disassemble the device, clean the contacts and check the sensor using a tester. If necessary, it must be replaced. If you do not have the skills to disassemble and repair such products, then you can take the remote control to any workshop specializing in electronics.

Error type "E1"

A decrease in pressure in the heating system was recorded. The simplest case that leads to this problem is a breakdown of the minimum pressure switch or a lack of signal between the sensor and the control board. However, first of all, you need to immediately check the heating circuit for leaks.

Leaking pipes or radiators can occur in places where the presence of water is not immediately noticeable. These are interfloor ceilings, storage rooms or basements. Therefore, you need to sequentially go around the entire circuit

Coolant leakage can occur not only in the circuit, but also in heating equipment components, such as:

• heat exchangers;
• hydraulic pump;
• relief valve;
• make-up tap, etc.

In this case, the hydraulic unit will have to be changed, although sometimes replacing the gaskets may be sufficient.

The supply may also be cut off for some reason.Although in this case the issue of leakage also arises, which is gradual.

A decrease in pressure in the circuit without coolant leakage can occur in the event of a fall pressure in the expansion tank closed type, which is installed in the boiler. In this case, it will have to be repaired.

After eliminating the cause of the leak, it is necessary to fill the circuit and restore the operating pressure.

Error type "E2"

Triggering of a gas analyzer, signaling incomplete combustion of the supplied mixture or smoke entering the chimney.

The problem lies in insufficient traction, which can be caused by:

• Change in the open cross-section of the smoke exhaust duct as a result of its contamination. It happens rarely, mainly due to a foreign object or small animal getting into it. Icing is also possible in the area where the pipe exits. Gas boiler chimney needs to be cleaned.
• Strong wind pressure. A difficult case, since it is necessary to recalculate the geometry of the pipe or install a windproof structure.

There may also be a problem with the fan. Most often, this is contamination of the blades, which can be seen, or a rotation disorder, which is easy to hear.

The chimney for a gas boiler has parameters different from the exhaust for stove heating. The fact is that the temperature in the boiler burner is relatively low, so the draft force will be less

You can identify the problems described above yourself. If the chimney and fan are functioning normally, there is still a possibility of sensor failure. It will have to be replaced.

Error type "E3"

An error occurs when overheating is detected. coolant. There are two main reasons:

• malfunction of the emergency thermostat;
• slowing down or stopping coolant circulation.

If such an error occurs, you need to wait until the device has cooled down, reset it (turn it off and on) and start it again. If the error repeats, this means that the trigger was not false (this happens) and will have to be sorted out.

First of all, it is necessary to determine whether the coolant circulation rate is sufficient. To do this, you need to start the boiler without heating and listen to the operation of the pump. Its hum should be normal.

Problems with this node can be caused by several reasons:

• No power supply. You'll have to call the wiring and find a break.
• There is power, but the pump does not work. You need to show it to an electrician. If there is a break in the winding, it is cheaper to replace the entire assembly. If other wires break down, the problem can be eliminated and the pump will work again.
• Rotor shaft jamming. This event rarely occurs without damage, so it is best to replace the pump.
• Impeller wear. The pump needs to be replaced.

It is also possible that the contacts of the signal wire from the pump to the board are disconnected or the central board itself is damaged.

Poor coolant circulation can be caused by a clogged dirt filter. It needs to be cleaned periodically, but not everyone carries out this procedure on time.

If the pump is running at full power, then the cause of poor circulation is in the circuit. She may be:

• Reduced pressure in the system and failure of the pressure sensor. Rare case.
• Air lock formation. It is necessary to check the entire circuit by bleeding air through Mayevsky taps and similar fittings.
• Accidental closure of one of the shut-off valve elements. All taps and plugs must be checked.
• Formation of blockage. Rare case.A difficult problem primarily due to the difficulties associated with finding the location of the mud plug.

If the pump operates normally and the circuit normally passes coolant, then the temperature sensors need to be replaced. Most likely they are out of order.

Error type "E4"

This code signals the activation of a pressure switch - a draft sensor in the chimney. The main reasons are the same as for error code “E2”.

If the gas boiler chimney and fan are working normally, then the problem may lie in the signal from the sensor. First of all, you need to check the tightness of the connection of the contacts to the sensor and to the central board, and also check the wiring.

It is also possible that condensation may form in the tubes or that they are poorly connected to the sensor. Failure of the pressure switch itself is unlikely.

Error type "E5"

Receipt of an alarm signal from the flame sensor. If visually, when turning the boiler on and off, ignition occurs normally, then you need to check the flame sensor.

First of all, you need to make sure that it is in good contact with the main board (check the wire connection and test it). You also need to make sure that there is a voltage of 5 Volts between the terminals of the CN05 sensor.

If there is no ignition, the problem may not be with the boiler. The position of the gas shut-off valve must be checked first.

If the sensor works normally and ignition does not cause problems, then the error is in the central board. It will have to be replaced.

If you can visually detect a problem with ignition, you must perform the following steps:

• Reset the unit and try to ignite again. Perhaps the reason is one of the capacitors or a residual charge on the ignition transformer.
• Make sure that the maximum and minimum gas pressure is properly adjusted for the injectors installed in the device. Standard indicators can be found in the instruction manual.
• Inspect the ionization electrode for contamination. Make sure that there is an acceptable gap between it and the burner device. Make sure there is a spark (by first shutting off the gas).
• Adjust the ignition power in the service menu. You need to use the parameters that are specified in the user manual.
• Make sure that there is no breakdown on the body (that is, the user does not receive an electric shock when touching the boiler elements).
• Make sure that the grounding is present and not broken.
• Check that the gas valve is not stuck. Simply insert the silicone tube into the fitting and press firmly.
• Check for a broken valve coil.

If the problem is in the gas valve, it will have to be replaced.

Often, a broken gas valve coil (above) and other electrical problems can be recognized visually or identified by the characteristic smell of burnt wiring

Using this error as an example, it can be seen that sometimes to repair a Daewoo gas boiler, knowledge in several areas is needed: electrical, electronics, and mechanics. Therefore, in case of complex errors, it is still better to call experienced gas service technicians, who will contract signed for the supply of blue fuel and maintenance of units.

Error type "E6"

Gas leak sensor triggered. If you smell gas in the boiler room, you must first turn off the shut-off valve at the entrance to the house. Then you need to check the gas pipeline (up to the boiler valve) and fittings for damage. If you find them, you should contact your gas service.

If the smell of gas is not felt, then after a while you can start the boiler again. It is advisable to be nearby at this time and have a gas analyzer with you. If the sensor triggers falsely, it needs to be replaced.

Error type "E7"

This code is displayed if the board has “lost” the remote control. The problem may be a breakdown of the control panel or the board unit responsible for communication.

Control devices from other Korean manufacturers (Navien, Hydrosta, etc.) are suitable for Daewoo boilers, so there is no particular problem in replacing this part.

Error type "E8"

Lost connection between the heating circuit temperature sensor and the central board. Typically, the problem occurs when the thermistor breaks. First, of course, you need to see if the contacts have come loose, then call the wiring. If it is working properly, then the sensor should be replaced.

You can replace the sensor yourself. All modern measuring devices for this purpose are equipped with special sockets, so you don’t have to solder anything

Theoretically, a breakdown of the central board unit is possible, although usually in this case it fails completely, rather than partially.

Error type "E9"

Leak in the boiler. The water presence sensor has tripped. You need to open the boiler and look where the fistula has formed. There may also be a problem with the gaskets of the sockets where the heating and hot water temperature sensors are installed.

Error type "EA"

The circuit is refilled with water more often than once every 5 minutes. This indicates the presence of a leak. Its volume is not so significant as to stop the boiler as a result of boiling water or releasing pressure.

This situation cannot be ignored, since a small leak at any moment can turn into a full-fledged leak with an emergency stop of the boiler and serious consequences for objects in the house.

Error type "EC"

Central control boards are universal for all models within the same line. The error code “EC” indicates that the boiler model was incorrectly selected. This usually occurs when the central board is replaced or when parameters are reset due to a sudden power outage.

It is customary to install a stabilizer in front of a gas boiler. This allows you to avoid breakdowns of expensive electronics and equipment downtime during the heating season.

To solve this problem, just configure the settings using the service menu.

Error type "Ed"

The second letter of this code is lowercase “d”. Manufacturers moved away from the template so that users do not confuse the capital “D” and the number “0”, which have similar shapes. The error means that the built-in stabilizer has detected a deviation in the current frequency.

If power parameters often deviate from standard values, the boiler electronics may fail.

Error type "EE"

This code indicates a problem with the smoke exhaust fan. The speed sensor shows a low value.

The malfunction may be caused by:

• clogged impeller;
• violation of shaft lubrication;
• inaccurate sensor readings.

Also, a board error cannot be ruled out, although this option is unlikely.

Error type "EF"

A signal that the three-way valve responsible for switching the water flow has been open for more than 90 minutes. This indicates that it is jammed. To prevent this damage, it is necessary to install a filter that will prevent clogging.

The three-way valve is equipped with power wires and a communication cable with the central board. If the “EF” error occurs, first of all you need to ring the wiring and secure the contacts well

The most serious failure is a burnt out valve servomotor. In this case, it is better to replace the entire distribution assembly.

Error type "U0"

The flame sensor does not “see” the fire. Ignition problem. If the flame lights up and goes out, the reason may be the quality of the supplied mixture, gas pressure or lack of exhaust hood.

The chemical composition of liquefied gas differs from the main gas. Each specific mixture has its own set of burner nozzles. Don't forget to supply the appropriate kit.

If the flame lights up, the auto-ignition electrode continues to click, but the error still remains, then the reason may be a defective sensor or a poor connection to the board.

One of the defects of the sensor is simply its contamination. If you wipe this part, the problem is often solved.

Error type "U1"

The buttons on the control panel are stuck. Such repairs do not relate directly to the gas boiler, but can be carried out by any electronics specialist. To do this, you need to disconnect the panel from the boiler body and take it for repair.

Error type "U8"

Hot water temperature sensor error. The reasons for the breakdown and the necessary actions in this case are similar to the situation with error “E8”. The boiler does not stop its operation, but operates only in heating support mode.

While replacing the sensor, the boiler will need to be stopped and disconnected from the power supply.

Error type "U9"

Signal from a temperature sensor located in the chimney. The most likely situation is clogged pipes. They need to be cleaned.If no contamination is detected, then the problem may be with an uncorrected sensor.

Almost half of the stoppages of the Daewoo gas boiler are associated with problems that arose in other components of the heating circuit.

In addition, many boiler malfunctions can be eliminated independently if you have at least minimal skills in repairing any equipment. Therefore, it is necessary to analyze the type of error and only after that make a decision either to repair it yourself or to call specialists.

Conclusions and useful video on the topic

Replacing the heat exchanger of Daewoo MSC series boilers:

Determining the type of fault associated with the flame ignition electrode:

Instruction for a specialist in working with MSC series boilers. Suitable for other Daewoo lines. Strict adherence to these recommendations prevents the occurrence of many malfunctions:

It should be remembered that improper handling of flammable gas can lead to an emergency situation - a fire or explosion. Therefore, if you have doubts about the ability to solve the problem yourself, you need to call technicians from the service center or gas service.

Tell us about your own experience in identifying and eliminating breakdowns of Korean-made gas units. It is possible that your advice will be useful to interested site visitors in solving their problems. Please leave comments in the block below, ask questions and post photos on the topic of the article.