Buderus Combi Boiler Error Codes
Buderus Combi Boiler Error Codes

Buderus Combi Boiler Error Codes

Buderus Combi Boiler Error Codes If there are interruptions in the operation of the Buderus boiler, do not rush to repair it yourself or call a boiler repairman. To get started, use the built-in self-diagnosis function. The boiler will immediately tell you an error code that will help you localize the problem and find the right way to repair it. IMPORTANT! Any physical intervention in the operation of the boiler should be entrusted to service center employees. Attempts to fix the problem yourself can greatly increase its consequences.

Buderus Boiler Error Code Solutions

Error codes for wall-mounted heating boilers Buderus Logamax 

The code

Fault

Working codeDescription
-A208The boiler is in the “chimney sweep” mode. After 15 minutes, the “chimney sweep” mode is automatically deactivated
-H200The boiler is in heating mode.
=H201Boiler in DHW mode
0A202Cyclic interlock active: the delay time between switching off and switching on the burner has not yet expired

(service function 2.3b).

0A305Keep warm duration for GB072-24K: keep warm interval

hot water has not yet been exhausted (service function 2.3F).

0C283The burner turns on
0E265The heat demand is less than the minimum heat output of the boiler. The boiler is in operation

on-off.

0H203The boiler is in a state of readiness, there is no need for heat.
0L284The gas valve opens, the first delay time.
0U270The boiler starts up.
0Y204The actual flow temperature is higher than the set temperature. The boiler is switched off.
2E357The venting function is active.
2H358Anti-jamming protection for the heating circuit pump and 3-way valve is active.
2P342Limitation of gradients: temperature increase too fast in domestic hot water mode.
5H268Boiler test by control system
H11Defective hot water temperature sensor (GB072-24K)Disconnect the temperature sensor.

Check temperature sensor, replace if defective

Check the connecting cable for breaks and short circuits, replace if defective.

0Y276Temperature at flow sensor > 95 °C.This message may appear without a malfunction if all the valves on the radiators suddenly close or after hot water is drawn from the GB072-24K.

Check the operating pressure in the heating system.

Open the service taps.

Connect the heating circuit pump electrically to the BC20 main controller.

Check or replace the heating circuit pump.

Correctly set the pump power or characteristic curve and adjust to the maximum power.

Check for damage or short circuit in the flow temperature sensor and its wires, replace if necessary.

0Y359High temperature on the hot water temperature sensorCheck the correct position of the temperature sensor

Check for damage or short circuit in the temperature sensor and its wire, replace if necessary.

Insert the KIM correctly, replace if necessary

2P341Gradients limitation: too fast temperature rise in heating modeCheck the operating pressure in the heating system.

Open the service taps.

Connect the heating circuit pump electrically to the BC20 main controller.

Check or replace the heating circuit pump.

Correctly set the pump power or characteristic curve and adjust to the maximum power.

3A264Fan not workingCheck the fan and its cable with plug, replace if necessary.
3F273The burner and fan have been running for 24 hours without interruption and are switched off for a short time for safety reasons.
4C224The heat exchanger temperature limiter or the flue gas temperature limiter has trippedIf a blocking fault is present for a long time, then it turns into a locking fault.
4U350Flow temperature sensor defective (short circuit).If the fault is present for a long time, the display will show fault code 4U and operating code 222
4Y351Flow temperature sensor defective (break).If the fault is present for a long time, the display will show fault code 4Y and operating code 223
6A227The flame was not detected.After the 4th ignition attempt, the blocking fault turns into a locking one.
6L229No ionisation signal during burner operation.The burner restarts. If ignition is unsuccessful, a 6A lockout fault will be displayed, after the 4th ignition attempt, the lockout fault will change to rapier.

 

8Y232The temperature control relay has tripped

AT90.

Check the setting of the AT90 temperature monitor.

Check the heating control setting.

8Y232Faulty monitoring relay

temperature AT90

Check for damage or short circuit in the temperature sensor and its wire, replace if necessary.
8Y232There is no jumper between the terminals of a separate monitoring relay

temperature AT90.

If no temperature control relay is connected, install

jumper.

8Y232Temperature control relay

blocked

The condensate pump is not working.

Unlock the temperature monitor.

Check the condensate drain.

Replace the condensate pump.

EL290Faulty main regulator BC20Replace main regulator BC20.
3C217The fan is not working.Check the fan and its cable with plug, replace if necessary.
3L214The fan has turned off during the delay time.Check the fan and its cable with plug, replace if necessary.
3P216The fan is running too slowly.Check the fan and its cable with plug, replace if necessary.
3Y215The fan is running too fast.Check the fan and its cable with plug, replace if necessary.

Check the flue gas system, clean or repair if necessary.

4C224The heat exchanger temperature limiter or the flue gas temperature limiter has tripped. Check for damage to the temperature limiter of the heat exchanger and its connecting cable, replace if necessary.

Check the flue gas temperature limiter and its connecting cable for damage, replace if necessary.

Check the operating pressure in the heating system.

Check temperature limiter, replace if necessary.

Check the pump pressure, replace the pump if necessary.

Check fuse, replace if necessary.

Vent the boiler.

Check the water circuit of the heat exchanger, if

replace if necessary.

For boilers with a splitter in the heat exchanger, check that a splitter is installed.

4U222Flow temperature sensor defective (short circuit).Check for damage or short circuit in the temperature sensor and its wire, replace if necessary.
4Y223Flow temperature sensor defective (break).Check for damage or breakage of the temperature sensor and its wire, replace if necessary.
6A227The flame was not detected.Check the protective conductor connection.

Check that the gas cock is open.

Check the gas supply pressure

Check the electrical connection.

Check electrodes with wires, replace if necessary.

Check the flue gas system, clean or repair if necessary.

Check the gas-air ratio, correct when

need.

For natural gas: check gas flow switch, replace if necessary.

When working with combustion air intake from a room, check the air supply to the room and the ventilation openings.

Clean the drain of the condensate trap

Dismantle the membrane in the fan mixer, check for cracks and dirt on it

Clean the heat exchanger

Check the gas valve, replace if necessary.

Insert KIM correctly, replace if necessary.

Two-phase network (IT): set a resistance of 2 ohm between PE and N at the connection of the electronic board to the mains.

6C228Although the boiler is switched off, a flame is detected.Check electrodes for contamination, replace if necessary.

Check the flue gas system, clean or repair if necessary.

Check the electronic board for moisture, dry if necessary.

6C306After turning off the gas supply, a flame was detected.Check the gas valve, replace if necessary.

Clean the condensate trap.

Check electrodes and connecting wires, replace if necessary.

Check the flue gas system, clean or repair if necessary.

7L261Time error at first delay timeReplace main regulator BC20.
7L280Time error when trying to restartReplace main regulator BC20.
9L234Faulty coil or connecting wire of the gas fittingCheck wires, replace if necessary.

Replace gas valve.

9L238Faulty gas valveCheck wires, replace if necessary.

Replace gas valve.

9P239KIM is not recognized.Insert KIM correctly, replace if necessary.
EL259Faulty KIM or BC20 master regulator.Replace KIM.

Replace main regulator BC20.

Fault codes for gas boilers Buderus

MalfunctionPossible causes of malfunctionRecommendations
The burner does not turn onIs the heating emergency switch in the On position?Turn on
Is the control system start switch in the On position?Turn on
Are the circuit breakers ok?Check their performance, if necessary, replace the defective machine.
Is the boiler water temperature controller connected?Check and, if necessary, replace defective parts.
Safety temperature limiter connected?Check and, if necessary, replace defective parts.
Error message from external safety devices (e.g. safety water level monitor)?The user must check the heating system, rectify the fault and, if necessary, replace the defective device.
Was the flue gas control system activated?AW 10: Reset the flue gas control system. AW 50: Wait a maximum of 15 minutes. The boiler will turn on automatically if there is a demand for heat. If triggered repeatedly, check the flue gas path and check the function of the flue gas monitoring system. If there is a defect, then replace.
The burner starts and switches to fault. No spark on ignition.Is there a sound when an ignition spark is generated when the ignition cable is removed?If not, then: replace the ignition transformer. If yes, then: Replace ignition electrode or ignition burner.
Burner starts and switches to fault.Are all gas shut-off valves open?Open gas shut-off valves.
Natural gas supply pressure > 8 mbar?If not, then: find the cause and rectify the fault.
Has the air been removed from the pipeline?Remove air until ignition of the gas is possible.
The burner starts and switches to fault. No ionization current.N and L connections reversed?Eliminate the error.
Is there voltage between L and PE?If not, then: Ground the PE, in this case install an isolating transformer.
Poor contact of the ionization wire?Eliminate the error, in this case, replace the defective part.
Short to ground on the ionization electrode?
Defective burner control?
The burner starts and switches to fault. Ionization current < 1.5 mA.Is the core or ceramic of the ionization electrode dirty?Clean the ionization electrode, if necessary replace the pilot burner.
Boiling soundsLimescale deposits or scale formation in the boiler?Clean the water circuit of the heating boiler in accordance with the manufacturer’s recommendations. With constant loss of water, determine and eliminate the cause. If required, carry out water treatment and install a dirt trap

Fault codes for combined boilers Buderus Logano

Fault codePossible causes of malfunctionRecommendations
The burner does not turn onIs the heating emergency switch in the On position?Turn on
Is the control system start switch in the On position?Turn on
Are the circuit breakers ok?Check their performance, if necessary, replace the defective machine.
Is the boiler water temperature controller connected?Check and, if necessary, replace defective parts.
Safety temperature limiter connected?Check and, if necessary, replace defective parts.
Error message from external safety devices (e.g. safety water level monitor)?The user must check the heating system, rectify the fault and, if necessary, replace the defective device.
Was the flue gas control system activated?AW 10: Reset the flue gas control system. AW 50: Wait a maximum of 15 minutes. The boiler will turn on automatically if there is a demand for heat. If triggered repeatedly, check the flue gas path and check the function of the flue gas monitoring system. If there is a defect, then replace.
The burner starts and switches to fault. No spark on ignition.Is there a sound when an ignition spark is generated when the ignition cable is removed?If not, then: replace the ignition transformer. If yes, then: Replace ignition electrode or ignition burner.
Burner starts and switches to fault.Are all gas shut-off valves open?Open gas shut-off valves.
Natural gas supply pressure > 8 mbar?If not, then: find the cause and rectify the fault.
Has the air been removed from the pipeline?Remove air until ignition of the gas is possible.
The burner starts and switches to fault. No ionization current.N and L connections reversed?Eliminate the error.
Is there voltage between L and PE?If not, then: Ground the PE, in this case install an isolating transformer.
Poor contact of the ionization wire?Eliminate the error, in this case, replace the defective part.
Short to ground on the ionization electrode?
Defective burner control?
The burner starts and switches to fault. Ionization current < 1.5 mA.Is the core or ceramic of the ionization electrode dirty?Clean the ionization electrode, if necessary replace the pilot burner.
Boiling soundsLime deposits or lime scale in the boiler?Clean the water circuit of the heating boiler in accordance with the manufacturer’s recommendations. With constant loss of water, determine and eliminate the cause. If required, carry out water treatment and install a dirt trap

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