Bosch boiler errors - Meaning, causes and elimination

We have such a problem. The Bosch boiler is double-sided, we have been using it for only six months. They turned on hot water, but it does not heat up, knocks out the boiler and shows error E9. The filter was cleaned, the device started up, but after an hour it turned off again. Shows an error. When we start, the pressure immediately rises and the unit is cut down. Then we turn it on, the fuses immediately burn out and the boiler goes out. So we can't turn it on. Please help in
what could be the reason?

Most likely your pump is stuck. Usually the fuses are blown because of the pump.

Bosch gas boiler 6000w. Was purchased in August this year. As a sharp cold snap came, it turned off and showed error C6 (the differential pressure switch does not turn on). After removing the front cover, it was found that the tubes that fit this relay were covered with frost. After drying the tubes, the device started up. This situation has been repeated several times. Is there any way
get rid of this problem?

You need to look at how the smoke exhaust system is made. A separate system often leads to such consequences. We recommend replacing with coaxial. If it is not possible to change the chimney, then the pipes must be insulated.

Wall boiler Wbn 6000-24. Gas is natural. It's been a long time since the EA bug. After reading about the EA error, I decided to find out the firmware of the board and the fan stage settings. If the software version in the menu displays "245-03" and, as it were, raises no questions, then the fan steps menu showed the number "17". The flue system is horizontal with a concentric pipe. The exit from the boiler is about 2 meters. No fence adapter
I have not installed air from inside the room and the air enters the unit from outside the room. What guided the masters by installing the 17th stage of the fan, although, judging by the instructions, the 2nd stage is needed. Do I need to change the board?

An adapter is not needed. You have a standard coax with air intake from the outside. It helps to get rid of this error by setting the fan stage to 5. I had the same thing, and when I set it to 5, there was no error for a year already.

Tell me, does the burner activate modulation only when using a thermostat or in some other cases?

When the temperature of the coolant approaches the set modulation of the boiler, it turns on in any case, regardless of whether there is a thermostat or not, but since this process takes a little time, it is difficult to fix it. If an OT thermostat is used, modulations begin to occur when the room temperature approaches the set temperature. If the "On / Off" thermostat is set, then there is no connection.

Private house 70m2 300mm foam block 50mm mineral wool and ceramic brick cladding. There are plans to expand the area by another 50-60 square meters. m. On the ground floor, TP 33m2 are installed, heating batteries are installed on both floors. Hot water supply is realized by the kitchen and bathroom, in the future there will be a second bathroom. I want to install BKN Drazice 125. Since a riser is installed in my house, I plan to install a wall gas boiler With
coaxial chimney. considering different variants. The most optimal price is Bosch 6000 (18 kW), but bosch gaz 7000 has a minimum power of 24 kW, which, I think, is too much for me. Of the important, I need the boiler to be able to set the temperature in the boiler and, in the future, it would be possible to mount a room thermostat and an outdoor sensor. Interested
the difference between the indicated models in terms of the composition of components or in the place of assembly? Maybe there are other fundamental differences?

In your case, the most optimal model would be bosch gaz wbn6000-18 and wstb 120.

Bosch WBN 6000 boiler error codes

Error A7- Malfunction of the DHW temperature sensor. Inspect the sensor for a defect or short circuit and its wiring. Replace if necessary.

Ad error- The unit cannot detect the boiler temperature sensor. It is required to inspect the boiler temperature sensor and connecting wires.

Error C1- The fan rotates at a low frequency. You need to check the mains voltage. Also inspect the flue gas system and, if necessary, clean or repair it.

Error C4- No opening of the differential pressure switch if the fan is off. The diff needs to be checked. pressure switch.

Error C6- The differential pressure switch does not close. Check the fan and wires with plugs. Perform replacement if required. Check diff. pressure switch and pipes for the output of combustion products.

Error C7- The fan does not work. Check the fan and its wires with plugs. Perform replacement if required.

CE error- Not enough pressure in heating system. Water needs to be filled.

error d7- Fault gas system. Check the connecting wire. Inspect the gas system and replace if necessary.

Error E2- Malfunction of the temperature sensor on the supply line (break). It is required to check for possible damage or short circuit of the sensor and its wiring. Replace if necessary.

Error E9- The temperature limiter is activated in the heat exchanger. It is necessary to check for possible damage to the temperature limiter of the heat exchanger and its connecting wires. Perform replacement if necessary. Check the nominal pressure in the system. Inspect the temperature limiter and replace with a new one if necessary. Run a startup check circulation pump and if
necessary, replace it. Check fuses, change if necessary. Remove air from the unit. Check the water circuit in the heat exchanger. If necessary, replace. Check the flue gas temperature limiter for possible damage.

EA error- No flames. Check connection of protection wires. See if open gas cock. Test the gas supply pressure reading and correct if necessary. Check connection to electrical network, electrodes with wires and, if required, replace. Inspect flue system, clean or repair. Carry out a gas adjustment check, correct if necessary. For natural gas: Inspect the switch controlling the gas flow. Change if necessary. When working with combustion air intake from the room, check the air supply to the room and the ventilation openings. Clean the heat exchanger. Check gas system, replace if required.

F7 error- When switched off, the boiler detects a flame. Check electrodes for oxidation, replace if necessary. Inspect output system combustion products and, if necessary, clean or repair. Check for moisture in the electronic control board, dry if necessary.

FA error- Defined a flame when the gas supply is turned off. Check the gas system, replace if necessary. Inspect electrodes and connecting wires, replace if necessary. Inspect flue system, clean or repair.

Error P- The boiler type is not defined. Set the implement type.

Fd error

Bosch ZWC MFA boiler error codes

Code A2, C3- Flue gas outlet at the combustion chamber. Check the heat exchanger for clogging.

Code A3- Indefined temperature sensor flue gases. It is required to check the sensor and connecting cables for damage.

Code A4- Flue gas outlet at flow fuse. Carry out a flue gas outlet test.

Code A6- The temperature sensor in the combustion chamber is not defined. It is required to check the sensor and connecting cables for damage.

Code A7- Malfunction of the temperature sensor for hot water supply (DHW). Check for defects or short circuits in the temperature sensor and its wiring, if necessary, replace.

Code A8- Contact with the BUS bus has been interrupted. Check contact cable and regulators.

Code A9- Incorrect installation of the DHW sensor. Check the mounting distances, if necessary, remove the sensor and mount it again using heat-conducting paste.

AC code- The module is not defined. The module is not connected correctly. Check the module, outside temperature sensor, remote control and contacts.

Ad code- The unit cannot detect the boiler temperature sensor. It is required to inspect the boiler temperature sensor and wire contacts.

Code b1- Coding plug not defined. Conduct correct installation coding plug, measure and replace if required.

Codes C1, C6- The differential pressure switch does not close. Check the fan and wires with plugs. Perform replacement if required. Check diff. pressure switch and pipes for the output of combustion products.

Code C4- Diff. the pressure switch does not open in the off position. Perform differential pressure switch test.

Code CC- The control unit cannot detect the outside temperature sensor. It is required to inspect the sensor and the contact cable for a break.

Code d3- Jumper 161 not found on ST8. If there is a jumper, insert the plug correctly, check the external limiter. Otherwise: check if there is a jumper.

Code d4- There is a large temperature difference. Check circulation pump, bypass hose and system pressure.

Code d5- The external temperature sensor is damaged. Check sensor and connecting contacts.

Code E2- Flow temperature sensor defective. Check sensor and connecting contacts.

Code E9- A limiter has tripped in the supply line. Perform a pressure test in the system, temperature sensors. Check the functions of the pumps and the fuse for control board, bleed the unit.

Code EA- No flame detected. Check the gas valve. Check the pressure in the gas network, the mains connection, the ignition electrode with wire and the ionization electrode with cable.

Code F0- Internal malfunction. Check the correct connection of the electrical plug contacts and starter lines, if necessary, replace the electronic board.

Code F7- The flame is detected when the unit is off. Check the electrodes and cables. The flue gas removal system may be defective. Check control board for moisture.

FA code- Flame detection after turning off the gas supply. Check the ionization electrode. Check gas system.

Fd code- Incorrect button pressing (duration more than 30 seconds). Press the button again less than 30 seconds.

Faults and adjustments of Bosch boilers

Bosch assures that its heat exchangers are not covered with a special protective anti-corrosion paint. Heat exchangers from other companies (Viessmann, Vaillant, Ariston, Baxi) have protective layer, and they have pure copper. And they expose it as the advantages of their models. Is this true or is it just a cheapening of the cost of the device.

Copper is really not subject to corrosion, which is why it is used. But due to its properties, copper burns rather quickly.

As far as I know, there are two options for connecting the BKN to a double-circuit gas boiler. First, through three-way valve. The second, through the hydraulic separator. In both cases, it is used as a consumer for the heating system, respectively, it will heat up from the temperature of the heating system. This is clear to me. But I don’t understand what to do with the DHW taps, and whether it is possible to simply put plugs on them. At first I
I assumed that I would buy a Bosch 6000 single-circuit boiler, but since it was not available, I was recommended to opt for a double-circuit one. And I'm thinking, if I plug the outlets, will the heat exchanger suffer (won't it burn out without water)? Since I won’t keep the unit constantly running at maximum, let the BKN continue to work. Moreover, I bought an ACV Comfort 130, and it is a tank in a tank by design and, in fact, should keep the temperature better than with a coil. Among the disadvantages of such boilers is the maximum pressure of 3 bar, and safety valve also pressure. A knowledgeable people they report that if the valve does not work for some reason, the tank will burst. Pro double-loop model- I am afraid that if the boiler fails, I will not be able to hot water stay.

Your conclusions are correct only for purified water. For domestic needs, you can set up a backup line. But in my memory, there have never been cases of failure of ACV boilers.

In a private house, I organize a separate smoke exhaust system for a 24 kW Bosch 6000 gas boiler. In this regard, I have two questions. Exhaust tract. Is it worth switching from "pants" 80-80 through a tee with a condensate drain to a diameter vertical chimney 100 mm? Pipe cost different diameter not very different from each other. Chimney height up to tee 4800 mm. I bring the pipe through the roof,
considering 10 degrees. intake tract. I'm going to organize the air intake in an unheated and well-ventilated attic. Before outer wall about 4 meters. Take air from the room good decision. The distance from the intake point in the attic to the upper plane of the unit is about 1050 mm (moreover, inside the boiler room 800 mm of the entire length). In winter, such a solution can create a number of problems,
the main one is that the apparatus will be supplied with air from outdoor temperature. It is also possible that strong condensation will form on the air duct, which will descend onto the housing. But if condensation can be fought with thermal insulation, then how to solve the problem of warm air I do not understand. As an option, I considered it to feed the air duct from the chimney of the bath (you will need to weld
water register with a diameter of 300-500mm). Organize the circulation in the register by a separate circuit. It is very difficult, but should give a result. Tell me, which chimney kit is suitable for installation on wbn 6000-24 c? It is necessary to bring the chimney immediately beyond the wall with a thickness of 375 mm, you will not need to pull it anywhere further. Since the prices for branded equipment are very high, I would like to try another manufacturer.
Neva, for example. Will it be possible to reprogram a single-circuit unit if the DHW flow sensor is turned off before that?

No. It will be necessary to replace the control board of a single-circuit boiler and the hydraulic unit from it. And also additionally install a three-way valve.

Recently, the heat exchangers of the Bosch 6000 gas boiler were washed. It worked for a month and kept the pressure at 1 all the time. Then it attracted a strange murmuring sound inside it before the burner was ignited (in the cooling mode), as if water was being poured from one mug to another. I looked, and the pressure was 0. In theory, it should have automatically turned off when the pressure in the system dropped to 0.5, but it worked and warmed the batteries.
The only thing that appeared was a different sound and murmur. I added the pressure to 1, but the next day the pressure dropped back to 0.5 (meaning there is a water leak somewhere). I checked the pipes and radiators, but found no leaks anywhere. It does not drip from the unit either, but the pressure still drops. Tell me what could be
problem and where to find it?

I had a similar one. In the system, the air and after the operation of the device, the air came out, and the pressure dropped. Is your automatic air vent valve (on top of the pump) not closed? It needs to be always open. It is better to bring the pressure up to 2 atm, so that the expansion tank in the boiler also takes the volume and compensates for the outgoing air. In radiators, of course, also bleed air with a Mayevsky crane.

The Bosch 6000 24 kW gas wall-mounted boiler often gives an EA error and often turns on and off. That is, conditionally - I set it to a minimum of 40 degrees, literally 5 minutes and turned off, etc. I used to warm it up as it should, but now the first batteries are hot, the distant ones are barely warm, it doesn’t reach them. Works on return temperature, room thermostat No.

The EA error can be resolved by setting the fan stage to 5. If the unit turns off quickly, it means that its minimum power is too high for your system. It cannot give less than 8 kW. And you apparently have 5 radiators in the system. Here he heats this water and turns off. And why does it heat them up so quickly, the following malfunctions are possible: something is clogged or airy, or the first radiators need to be balanced so that the entire flow does not go only through them. Here it is necessary to look at the scheme of radiators and so on. Try setting the pump speed to maximum (value 3) and bleed the radiators.

Tell me who knows about: Wall-mounted gas boiler WBN 6000-18C RN. What are the production tests? Are they launched?

Everything was fine with me, I don’t think it was like that from the factory, most likely the storage was strange.

Tell me: the Bosch wall-mounted boiler stopped, the pressure rose to 3 bar, it gave an E9r error. Tried to restart earned, after 10 seconds. the pressure jumped to the maximum, I stopped everything, turned it off, released the pressure. I checked the gas pressure and it was fine. What could it be?

If the system is new, then the expansion tank is small, if the old one, then the expansion tank is faulty, or the recharge may be poisoning. In your case, the error expansion tank the most probable. If so, then option 2: pump up pressure, replace the tank.

After opening the hot water tap and igniting the burner, the Bosch boiler gives an E2 error (the flow temperature sensor is faulty). This happens in 10-15 seconds. After closing the tap, the error is removed by itself, and the boiler continues to work in heating mode. If the tap is opened again, the situation repeats. To complete the picture: An additional circulation pump is installed in the heating circuit, before its installation
the boiler even in heating mode showed an E2 error for a couple of seconds, and then changed it to E9 (the heat exchanger temperature limiter worked). Source of water supply borehole pump(water supply pressure from 2x to 3x without sudden jumps).

Possible reasons such: the own circulation pump is faulty (if it is only activated with the DHW mode), the strainer is clogged. The sensor should probably not be ruled out.

Boiler zwa 24. The concept has changed, a heat exchanger from zsa, a boiler sensor and a three-way valve are needed. I think they pay the same. In general, from a double-circuit it is necessary to make a single-circuit.

The manufacturer does not recommend such modifications. But if there is a desire, then you need to purchase a heat exchanger. The feed tubes are the same, but the outlets are different. On the 2-circuit there is a hole for make-up, but on the 1-circuit there is not. There are 2 options here. Change handset. Figure out how to plug the hole. The control boards are the same.

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Any equipment can break. The main thing is to quickly and effectively eliminate the breakdown. To facilitate the task, the Bosch gas boiler gives errors on the display. These symbols indicate the cause of the malfunction. You just have to find the decryption and start looking for the problem. And we will describe the ways to eliminate it below.

Features of the Bosch gas boiler

The double-circuit device is the most popular among users. It simultaneously works for hot water supply (DHW) and heating. Some models are equipped with two heat exchangers, which ensure uninterrupted operation of the system.

Power controls are located on the control panel. Therefore, heating can be adjusted to the area of the room. How does equipment switch from one circuit to another? For this, a three-way valve is provided. The operation of the boiler is focused on the main circuit - heating. When the mixer is opened, the valve switches the flow to the DHW system.

The circulation of the coolant is provided by the pump. Sensors control the device and, in case of deviations in operation, give a signal to the control module. As a result, error codes appear.

Errors and malfunctions

The table contains error codes that correspond to Bosch models WBN 6000-24C, Bosch ZSC 24-3 (35-3) MFA, ZWC 24-3 (28-3, 35-3) MFA, Bosch ZWE 24-4 (28-4), ZSE 24-4 MFA, Bosch ZWE 24-5 MFK, Bosch ZWE 24-4 (ZSE) MF.

Error code	What does	How to fix it yourself
A2	The combustion chamber smokes. The heat exchanger is clogged with soot and scale.	Clean the radiator. Remove soot with a brush. Scale is removed with reagents or a solution of citric acid.
A3	No signal from flue gas sensor.	Inspect the sensor wiring, tighten the contacts. Replace defective part.
A4	The carbon monoxide exits the flow fuse.	Clean the pipes and chimney from clogging with soot, debris, foreign objects. Make sure you have traction.
A6	There is no contact with the burner temperature sensor.	Diagnose the connections and the sensor itself.
A7	The water thermistor is out of order.	Diagnose the connections and the sensor itself.
A8	No contact with BUS.	Tighten the connections from the bus to the control module. Replace cable
A9	Incorrect connection of the DHW temperature sensor.	Make sure erroneous connection. Install the element correctly using heat conductive paste.
AC	The module is not recognized.	Inspect the wiring between the module and the display, information panel. As well as connections, outdoor thermometer.
Ad	No connection to water heater thermistor.	Run diagnostics on all contacts, sensor.
b1	The system does not find the coding plug.	Insert the plug firmly into the socket. Check out his contacts.
C1	Fan blades rotate too slowly (Bosch WBN 6000-24C). Short circuit pressure switch (Bosch ZWE 24-5 MFA, Bosch ZWE 24-4 (28-4), ZSE 24-4 MFA, Bosch ZSC 24-3 (35-3) MFA, ZWC 24-3 (28-3, 35-3) MFA).	Make sure the mains voltage is sufficient. Clean the fan blades, chimney shaft. Check the pipes leading to the relay. Install the correct part.
C4	The pressure switch does not work, does not open.	Diagnose and replace the element. When coding C6, additionally check the rotation of the fan.
C6	The relay does not close.
C7	Fan defective.	Reconnect the plug, repair the fan.
CE	The pressure in the heating system has dropped.	Open the make-up tap. Add water until the readings are correct.
SS/ d5	The system "does not see" the external temperature sensor.	Connect the cable tighter, make sure the part is working.
d3	Jumper 161 on ST8 not fixed.	If the jumper is in place, connect the plug correctly. Contact the service center.
d4	Temperature difference exceeded.	Conduct an inspection: pump; bypass. Measure pressure.
d7	The control valve has failed.	Diagnose the valve, its wiring. If defective, install a new part.
E0	There is a problem with the printed circuit board.	Reconnect the pins or install the work board.
E2	The supply line thermistor has failed.	Make a ringing of the element for an open, short circuit. Check connectors for oxidation, clean and replace parts.
E9 (11)	Signal from the temperature sensor of the heat exchanger.	What to do? Check: Connections and wires for breakage, damage, oxidation. Pressure in the heating circuit. If it falls below the mark, turn on the make-up. Thermal sensor for short circuit, break. Blocking pump. Unlock and repair. Electronic control module. The presence of air in the system. Bleed the air with Mayevsky taps. Clean the radiator from scale and dirt.
EA	Burner flame out.	How to fix the problem: Open the gas valve all the way. If the pressure in the system drops, contact the gas service. Voltage fluctuations in the network - with frequent surges, connect a stabilizer. Tighten connections. Clean the chimney of soot. Resume traction. Strip the ignition electrode, reinstall it in its original place when displaced. Run diagnostics on the gas controller. Inspect and, if found, remove deposits from the heat exchanger walls. Call a specialist to check the gas fittings and the control board.
er	Signal about the failure of one of the nodes.	Complete complete diagnostics boiler.
F0	Internal problem.	Inspect and reconnect the terminals and wires to the control module. Make sure they are intact. If everything is in order, change the module.
F7	The technique does not function, but the flame is detected.	Check if the flue is working properly. Confirm traction. Perform diagnostics of sensors, electrodes, cables.
FA	The fuel supply is shut off, but there is a signal about the presence of a flame.	Inspect the ionization electrode and the serviceability of the shut-off valves.
fd	Accidental pressing of a key on the panel.	Press the same button and hold for 30 seconds.
\| \|	Fan out of adjustment.	Carry out the adjustment.
P	Boiler type not defined.	Set type.
23	Fuel type specified.

Other malfunctions

In boilers "" there are problems that are not displayed as an error.

Burner not working

It is necessary to check the status and turn on the emergency and start switches. If one of the circuit breakers is defective, repair it or replace it with a working device.

Also carry out diagnostics of temperature controllers, outlet product relays. Do a preventive cleaning of the furnace, burner, nozzles, outlet pipes.

No spark, no ignition

Look for the problem in:

Ignition electrode. Strip it, place it closer to the burner.
burner.
Ignition transformer.

Noise and hum when the boiler is turned on

Clean the parts, including the heat exchanger, from scale. Salt deposits interfere with heat transfer, so the water boils and hisses. If plaque is not removed, the assembly will overheat and fail.

Hot water does not turn on

If there is no hot water when you open the faucet, inspect the three-way valve. If it breaks, it must be replaced. Also make sure that the mixer is in good condition, clean the pipes and filters from blockages.

Whistle when igniting the burner

The size of the nozzles does not correspond to the pressure in the gas line. Change them.

Black smoke and soot

The ignition unit needs to be cleaned. Parts and holes clogged with dust and dirt.

Claps, noise during ignition

What could have happened:

Gas supply set incorrectly.
Wrong nozzle size.
Chimney clogged.
Incorrect structure of the chimney shaft.
Poor ventilation in the room.

We hope that after reading the article, you will determine the cause of the breakdown. You can do the repair yourself if you are tech savvy. However, remember: before starting work, it is necessary to turn off the gas and water supply.

Bosch Gaz 6000 boiler errors

Error A7 - The hot water temperature sensor has a malfunction.

Error Ad - Boiler temperature sensor not defined.

Check boiler sensor and connection wires.

Error C1 - The fan rotates at a low frequency.

Check mains voltage.

Check flue gas outlet. If necessary, clean or repair.

Error C4 - The differential pressure switch does not open when the fan is not running.

Check diff. pressure switch.

Error C6 - The differential pressure switch does not close.

Check diff. pressure switch, as well as flue gas pipes.

Error C7 - The fan does not work.

Check fan, cable and plug. If required, replace.

CE error - Low pressure to fill the heating system.

Perform water refill.

Error d7 - There is a malfunction of the gas fittings of the Bosch 6000 wall-mounted boiler.

Check the connection wire.

Error E2 - Malfunction or breakage of the temperature sensor on the supply line.

Check the sensor for a defect, as well as a possible short circuit in its wire. Replace if required.

Error E9 - Operation of the heat exchanger temperature limiter.

Check the temperature limiter of the heat exchanger for a defect, as well as a possible short circuit in its wire. Replace if required.

Check the operating pressure in the heating system.

Check the temperature limiter, if necessary, replace it.

Check pump start. If required, replace the pump.

Check fuse, replace if necessary.

Remove air from the Bosch 6000 gas boiler.

Check the water circuit of the heat exchanger, replace if damaged.

Check the flue gas temperature limiter for a defect and a possible short circuit in its wire. Replace if required.

EA error - No flame found.

Check the connection of the protection wire.

Check the opening of the gas cock.

Check gas supply pressure. Troubleshoot if required.

Check the electrical connection.

Check electrodes and wires. Troubleshoot if required.

Check the flue gas outlet. If necessary, clean or repair.

Perform gas adjustment. Troubleshoot if required.

For natural gas: check the gas flow control switch. Troubleshoot if required.

When using a combustion air intake from a room, check the air draft into the room and the ventilation openings.

Clean the heat exchanger.

Inspect gas fittings. If required, replace.

Error codes for gas boilers Bosch ZSC / ZWC 24 MFA

A7 - The hot water temperature sensor is defective.

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

A8 - BUS connection interrupted.

Check connecting cable and regulators.

A9 - The hot water temperature sensor is incorrectly installed.

Check the installation area, if necessary, dismantle the sensor and reinstall it using heat-conducting paste.

Ad - Boiler sensor not detected.

Check boiler sensor and connecting cable.

b1 - Coding plug not found.

Insert the coding plug correctly, measure it and replace if necessary.

C1 - During operation of the device, the differential pressure switch has opened.

Check differential pressure switch, exhaust device and connecting pipes.

C4 - The differential pressure switch does not open when not in use.

Check differential pressure switch.

C6 - Differential pressure switch does not close.
Check differential pressure switch and flue pipes.

d3 - Jumper 161 not detected on ST8

If there is a jumper, insert the plug correctly, check the external limiter. Otherwise: is there a jumper?

d4 - Temperature difference too high.

Check pump, bypass hose and system pressure.

E2 - The flow temperature sensor is not working.

Check temperature sensor and connecting cable.

E9 - The limiter in the supply line has tripped.

Check the pressure in the system, check the temperature sensors, check the operation of the pumps and the fuse on the electronic board, bleed the air from the device.

EA - Boiler Bosch ZSC / ZWC does not fix the flame.

Is the gas cock open? Check the pressure in the gas network, mains connection, trigger electrode with cable and ionization electrode with cable.

F0 - Internal fault.

Check the tightness of the connection of the electrical plug contacts and jumper lines, if necessary, replace the electronic board.

F7 - Although the boiler is off, a flame is detected.

Check electrodes and cable. If flue gas extraction is working, check the electronic board for moisture.

FA - A flame has been detected after the gas supply has been turned off.

Check ionization electrode. Check gas fittings.

Fd - The button was mistakenly pressed for too long (more than 30 seconds).

Press the button again less than 30 seconds.

CC - Outside temperature sensor not detected.

Check the outside temperature sensor and connecting cable for damage.

Bosch gas boiler malfunctions

The burner does not turn on

Check the operation of the emergency switch of the heating system - If necessary, turn it on.

Check the operation of the start switch of the control system - If necessary, turn it on.

Inspect the circuit breakers - Check their operation, if necessary, replace the faulty circuit breaker.

Inspect the boiler water temperature controller - Check and replace the defective part if necessary.

Safety temperature limiter defective - Check and replace if necessary.

An error signal appears from external safety devices (e.g. safety device control of the water quantity) - Check the heating system, eliminate errors, if necessary, replace the defective device.

The flue gas monitoring relay - AW 10 is triggered: unlock the flue gas monitoring relay. AW 50: wait a maximum of 15 minutes.

The Bosch boiler will turn on automatically if there is a request for heat. In the event of repeated activation, check the flue gas path and the function of the flue gas monitoring relay. Replace the relay if it is defective.

The burner ignites and shuts down due to a fault. No ignition spark

There is a sound of ignition spark formation when the ignition cable is removed - If not: replace the ignition transformer.

If yes: Replace ignition electrode or ignition burner.

The burner ignites and shuts down due to a fault

Is the gas cock open? - Open the gas cock.

Natural gas supply pressure higher than 8 mbar - If not: find the cause and rectify the problem.

Has air been removed from the pipeline? - Bleed the air until the gas can be ignited.

The burner ignites and shuts down due to a fault. No ionization current

Perhaps the N and L connections are reversed - Eliminate the error.

Check voltage between L and PE - If not present: ground PE, if necessary install an isolating transformer.

Poor contact of the ionization wire - Eliminate the error, if necessary, replace the defective part.

Ionisation electrode shorted to ground - Burner control defective.

Boiling sounds

Whether there is a lime deposits or scale formation in the Bosch boiler?

Clean the water circuit of the heating boiler according to the manufacturer's recommendations.

If there is a constant loss of water, find and eliminate the cause.

If required, treat the water and install a dirt trap.

Flat main flame

Are the nozzles suitable for the supplied gas? - If not: install the correct nozzles.

Match holes supply and exhaust ventilation local regulations and requirements for the installation of gas equipment?

If there is insufficient air flow, the deficiency must be eliminated immediately.

Sharp whistle of the burner

Is it established correct pressure on injectors? - Check the set value, correct if necessary.

The burner smokes

Is there any noticeable dirt in or below the slots in the burner rods? - Carry out a wet cleaning of the burner as described in this manual.

Find the source of contamination and protect against further contamination.

Are the air inlets and outlets always operational? - Are there deposits or fibrous contamination on the surface of the heat exchanger?

Inspect through the cleaning holes and combustion chamber. Dry and, if necessary, wet clean the boiler as described in this manual.

Are the burner rods damaged or deformed, is there any deformation of individual slots? - Replace the burner rods, find and eliminate the cause of the fault.

Information: Damage or deformation only occurs when at least one of the above faults occurs.

The ignition of the burner is very loud, with loud noises burning, you can see the flame on the nozzles

Are the correct injectors installed? - Switch off the burner, install a new burner rod and correct the incorrect gas type setting.

Is the correct pressure set on the injectors? - The smell of flue gases in the room where the boiler is installed.

Flue gases coming out of the draft interrupter? - Determine the cause of the incorrect flue gas evacuation and rectify the fault.

If it is not possible to immediately eliminate the cause, the burner must be switched off.

Vacuum in chimney more than 3 Pa? Blockage in the flue gas path?

Are the chimney dimensions correct?

Do they work in the boiler room exhaust fans removing air from the room?

Automation and malfunctions of boilers Bosch Gaz 6000 W

Automatic control for gas boilers Bosch Gaz 6000 W

The control panel of Bosch 6000 W gas convection boilers with the Cotronic 3 data bus allows you to control the heating system depending on room temperature.

Two types of Bosch regulators are recommended for these wall-mounted convection gas boilers.

Programmable room temperature controller OpenThermTM CR12005

Rice. 7. Combination of the programmable room temperature controller OpenThermTM CR12005 with the control panel of the Bosch 6000 gas convection boiler

Purpose and functions:

OpenThermTM programmable thermostat for boiler control with Cotronic 3 data bus.

Communication with the controller via a two-wire bus.

Two-wire bus technology, reverse polarity protection.

Simple, intuitive settings for temperature control and hot water management.

Preset weekly programs with six switching points. Possibility to manually change the program for each day of the week.

LCD display with digital and graphic display of work status.

Display of the current heating and DHW temperature, outdoor temperature (only if a temperature sensor is present), indication of the boiler burner operation status and error codes.

Possibility of remote reset of the boiler error.

Using the OpenThermTM protocol.

The air temperature setting range in the control room is 7...39 °С with a setting step of 0.5 °С.

Room temperature controller TRZ 12-2

Fig.8. Combination of room temperature controller TRZ 12-2 (on/off) with control panel for gas convection boiler Bosch Gaz 6000 W

Description and functions of the controller

The TRZ 12-2 room temperature controller is recommended for on-off regulation of the burner flame and control of the circulation pump of gas wall-mounted boilers.

Weekly programming of time intervals.

Three operating modes: "Normal", "Economic", "Automatic".

Holiday function (up to 99 days).

Frost prevention function.

Display of date and current time, automatic change of summer/winter time (synchronization with the system).

Room temperature adjustment range from +5 to +39 °C.

Faults shown on the display of Bosch 6000 boilers

A7 - The hot water temperature sensor is defective.

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

Ad - Boiler temperature sensor not recognized.

Check boiler temperature sensor and connecting wire

C1- low frequency fan rotation.

Check mains voltage.

C4 - The differential pressure switch does not open when the fan is off.

Check differential pressure switch.

C6 - Differential pressure switch does not close.

Check differential pressure switch and flue pipes.

C7 - The fan does not work.

Check the fan and its cable with plug, replace if necessary.

CE - Insufficient filling pressure of the heating system.

Add water.

d7 - The gas fittings of the Bosch Gaz 6000 W wall-mounted boiler are faulty.

Check connecting wire.

E2 - Faulty flow temperature sensor (open circuit).

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

E9 - The heat exchanger temperature limiter has tripped.

Check for damage to the heat exchanger temperature limiter and its connecting wire, replace if necessary.

Check the operating pressure in the heating system.

Check temperature limiter, replace if necessary.

Check pump start, replace pump if necessary.

Check fuse, replace if necessary.

Remove air from Bosch 6000 W boiler.

Check the water circuit of the heat exchanger, replace if necessary.

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

EA - No flame detected.

Check the protective conductor connection.

Check if the gas cock is open.

Check gas supply pressure, correct if necessary.

Check the electrical connection.

Check electrodes with wires, replace if necessary.

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

Check gas setting, correct if necessary.

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 heat exchanger.

Check gas fittings, replace if necessary.

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OPERATION AND REPAIR OF BOILERS

Proterm Panthera Proterm Skat Proterm Bear Proterm Cheetah Evan
Ariston Egis Teplodar Cooper Atem Zhitomir Neva Lux Arderia Nova
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Boiler Bosch - Errors and their meaning

Bosch WBN 6000 boiler error codes

A7- Malfunction of the DHW temperature sensor. Inspect the sensor for a defect or short circuit and its wiring. Replace if necessary.

Ad- The unit cannot detect the boiler temperature sensor. It is required to inspect the boiler temperature sensor and connecting wires.

C1- The fan rotates at a low frequency. You need to check the mains voltage. Also inspect the flue gas system and, if necessary, clean or repair it.

C4- No opening of the differential pressure switch if the fan is off. The diff needs to be checked. pressure switch.

C6- The differential pressure switch does not close. Check the fan and wires with plugs. Perform replacement if required. Check diff. pressure switch and pipes for the output of combustion products.

C7- The fan does not work. Check the fan and its wires with plugs. Perform replacement if required.

CE- Not enough pressure in the heating system. Water needs to be filled.

d7- Faulty gas system. Check the connecting wire. Inspect the gas system and replace if necessary.

E2- Malfunction of the temperature sensor on the supply line (break). It is required to check for possible damage or short circuit of the sensor and its wiring. Replace if necessary.

E9- The temperature limiter is activated in the heat exchanger. It is necessary to check for possible damage to the temperature limiter of the heat exchanger and its connecting wires. Perform replacement if necessary. Check the nominal pressure in the system. Inspect the temperature limiter and replace with a new one if necessary. Carry out a start-up test on the circulation pump and, if necessary, replace it. Check fuses, change if necessary. Remove air from the unit. Check the water circuit in the heat exchanger. If necessary, replace. Check the flue gas temperature limiter for possible damage.

EA- No flames. Check connection of protection wires. See if the gas valve is open. Test the gas supply pressure reading and correct if necessary. Check the connection to the electrical network, the electrodes with wires and, if necessary, replace them. Inspect flue system, clean or repair. Check gas adjustment
eliminate if needed. For natural gas: Inspect the switch controlling the gas flow. Change if necessary. When working with combustion air intake from the room, check the air supply to the room and the ventilation openings. Clean the heat exchanger. Check gas system, replace if required.

F7- When switched off, the boiler detects a flame. Check electrodes for oxidation, replace if necessary. Inspect the flue gas system and clean or repair if necessary. Check for moisture in the electronic control board, dry if necessary.

FA- Defined a flame when the gas supply is turned off. Check the gas system, replace if necessary. Inspect electrodes and connecting wires, replace if necessary. Inspect flue system, clean or repair.

P- The boiler type is not defined. Set the implement type.

Bosch ZWC MFA boiler error codes

A2, C3- Flue gas outlet at the combustion chamber. Check the heat exchanger for clogging.

A3- Flue gas temperature sensor not defined. It is required to check the sensor and connecting cables for damage.

A4- Flue gas outlet at flow fuse. Carry out a flue gas outlet test.

A6- The temperature sensor in the combustion chamber is not defined. It is required to check the sensor and connecting cables for damage.

A7- Malfunction of the temperature sensor for hot water supply (DHW). Check for defects or short circuits in the temperature sensor and its wiring, if necessary, replace.

A8- Contact with the BUS bus has been interrupted. Check contact cable and regulators.

A9- Incorrect installation of the DHW sensor. Check the mounting distances, if necessary, remove the sensor and mount it again using heat-conducting paste.

AC- The module is not defined. The module is not connected correctly. Check the module, outside temperature sensor, remote control and contacts.

Ad- The unit cannot detect the boiler temperature sensor. It is required to inspect the boiler temperature sensor and wire contacts.

b1- Coding plug not defined. Install the coding plug correctly, measure it and replace it if required.

C1, C6- The differential pressure switch does not close. Check the fan and wires with plugs. Perform replacement if required. Check diff. pressure switch and pipes for the output of combustion products.

C4- Diff. the pressure switch does not open in the off position. Perform differential pressure switch test.

CC- The control unit cannot detect the outside temperature sensor. It is required to inspect the sensor and the contact cable for a break.

d3- Jumper 161 not found on ST8. If there is a jumper, insert the plug correctly, check the external limiter. Otherwise: check if there is a jumper.

d4- There is a large temperature difference. Check circulation pump, bypass hose and system pressure.

d5- The external temperature sensor is damaged. Check sensor and connecting contacts.

E2- Flow temperature sensor defective. Check sensor and connecting contacts.

E9- A limiter has tripped in the supply line. Perform a pressure test in the system, temperature sensors. Check the functions of the pumps and the fuse on the control board, bleed the air from the unit.

EA- No flame detected. Check the gas valve. Check the pressure in the gas network, the mains connection, the ignition electrode with wire and the ionization electrode with cable.

F0- Internal malfunction. Check the correct connection of the electrical plug contacts and starter lines, if necessary, replace the electronic board.

F7- The flame is detected when the unit is off. Check the electrodes and cables. The flue gas removal system may be defective. Check control board for moisture.

FA- Flame detection after turning off the gas supply. Check the ionization electrode. Check gas system.

fd- Incorrect button pressing (duration more than 30 seconds). Press the button again less than 30 seconds.

Faults and adjustments of Bosch boilers

Wall boiler Wbn 6000-24. Gas is natural. It's been a long time since the EA bug. After reading about the EA error, I decided to find out the firmware of the board and the fan stage settings. If the software version in the menu displays "245-03" and, as it were, raises no questions, then the fan steps menu showed the number "17". The flue system is horizontal with a concentric pipe. The exit from the boiler is about 2 meters. I have not installed any adapter for air intake from inside the room and the air enters the unit from outside the room. What guided the masters by installing the 17th stage of the fan, although, judging by the instructions, the 2nd stage is needed. Do I need to change the board?

Recently, the heat exchangers of the Bosch 6000 gas boiler were washed. It worked for a month and kept the pressure at 1 all the time. Then it attracted a strange murmuring sound inside it before the burner was ignited (in the cooling mode), as if water was being poured from one mug to another. I looked, and the pressure was 0. In theory, it should have automatically turned off when the pressure in the system dropped to 0.5, but it worked and warmed the batteries. The only thing that appeared was a different sound and murmur. I added the pressure to 1, but the next day the pressure dropped back to 0.5 (meaning there is a water leak somewhere). I checked the pipes and radiators, but found no leaks anywhere. It does not drip from the unit either, but the pressure still drops. Tell me what could be
problem and where to find it?

I had a similar one. In the system, the air and after the operation of the device, the air came out, and the pressure dropped. Is your automatic air vent valve (on top of the pump) not closed? It needs to be always open. It is better to bring the pressure up to 2 atm. expansion tank in the boiler, too, took the volume and compensated for the outgoing air. In radiators, of course, also bleed air with a Mayevsky crane.

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Borino, ZHMZ, Siberia, Alfa Kalor, Thermotechnician.
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