Boiler errors «“DEU” indicate the cause of the failure. Our publication lists all fault codes for this brand. Having studied their meanings, you will be able to cope with the breakdown yourself, and also learn how to prevent it.
Features of operation of the Daewoo boiler
Daewoo Gasboiler equipment of the entire series is double-circuit. Boilers simultaneously work on the heating system and hot water supply (DHW). Closed and open type chambers are suitable for various smoke extraction conditions.
Closed wall models with a turbocharged burner are connected to a coaxial chimney. The air for operation is taken from outside, the products of combustion are forced out by a fan. Atmospheric and forced units are equipped with two heat exchangers. Flame modulation burner saves on fuel consumption.
The design includes a circulation pump and an expansion tank for removing excess fluid when heated. An emergency control system is used. Sensors and sensors control the operation of all nodes, and failures are reported to the control board. Then a fault code is displayed on the display.
Heating boiler error codes
The equipment worked properly, but suddenly stopped and flashed an error code on the display? Don’t worry, it might be a system glitch. Restart boiler. If the same code is displayed after turning it on again, start troubleshooting.
| Malfunction code | Which means | How to fix a breakdown |
| E0 | The temperature sensor in the remote control has failed. | Disassemble the remote control, diagnose the sensor with a tester. If broken, replace the part. |
| E1 | The level of coolant in the heating system is reduced. | What to do:
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| E2 | The gas does not burn completely. Combustion products are poorly discharged. | Check for draft: bring a lit match to the window of the device. With normal draft, the flame will deviate to the side. Otherwise, clean the chimney, pipes, remove frost and snow in the winter. Inspect the thrust sensor for serviceability, its wiring with the control module. |
| E3 | System overheating. The temperature has exceeded 95 degrees. |
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| E4 | The traction sensor has tripped. | Check the presence of draft, replace the sensor, clean the chimney. To remove debris from the street, contact the municipal services. |
| E5 | Voltage increased when ignited. | Make sure the printed circuit board is working. Use a voltmeter to measure the readings of the contacts of the infrared sensor CN05. A good cell will show 5 V. |
| E6 | A fuel leak error has occurred. | Carry out diagnostics of gas control, stop valves, valves. If you smell gas in the room, contact the service immediately. |
| E7 | The unit has not communicated with the control panel for more than 1 minute. | Check:
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| E8 | The heating circuit thermistor has failed. | Make sure the sensor, its contacts are in good condition. Tighten the connections, reconnect the part. |
| E9 | There is a leak in the heating circuit. | Shut off the water supply. Inspect all connections for leaks. Isolate the damaged area and turn on the make-up to fill the system. |
| 4U1 | Problems with buttons on the control panel. | Dismantle the panel and inspect the contact groups. Strip them of corrosion. |
| U0 | The presence of a flame is not distinguished. | Adjust burner flame or replace flame sensor. |
| EF | Switchover valve open for more than 90 minutes. | Make sure the valve is not stuck. |
| EA | The product signals the filling of water 5 times in 1 minute. | |
| EC | Wrong model installed. | You may not have changed the settings after replacing the board. |
| Ed | The frequency of the current does not meet the standards. | Connect a voltage stabilizer. |
| U8 | The DHW thermistor is defective. | Replace the element with a new one. |
| U9 | Chimney pipe blockage. | Perform pipe cleaning, flue gas sensor diagnostics. |
Other problems
Not all breakdowns are displayed as symbols on the screen. Some you may notice during operation.
When hot water is turned on at the mixer, the burner does not start immediately. Hot air comes out after the fan has been running for 10 seconds.
The fan speed is too high. Repair or replace the assembly.
The front panel is closed, and ignition occurs only after the fan is turned on.
Due to the closed panel, resistance increases. Therefore, the fan blades rotate rapidly. Its replacement is required.
During heating, a knock and a rumble are heard.
Pump problems. The inner ball closes the outlet. Close the valves on the return pipe.
The circuit breaker has switched off.
The pump seal is broken. Water has entered the assembly, causing a short circuit. Carry out repairs.
No hot water.
Inspect the gas boiler for serviceability, a three-way valve that switches flows. Run PCB diagnostics.
The flame goes out after ignition.
Line pressure drops. Turn off the fuel valve to the stop, bleed the air from the system.
The quality of equipment performance depends on proper installation and operation. Do not forget that the user is half the responsibility for the duration of the equipment.
To avoid trouble, it is recommended to periodically clean the chimney, combustion chamber, heat exchanger. Carry out preventive maintenance of electronics, monitor the quality of water in the circuit. If your area has a high content of potassium and magnesium in the water, connect filters to reduce hardness. Then the scale will not settle on the nodes and parts of the boiler.