Vitodens 100-W, error F4, problems with ignition and flame retention

I have a boiler as in the topic = Viessmann Vidtodens 100-W (9-26kW) with the following problem ....

The display shows the error F4, which means according to the service manual:


The stove behaves as follows:
1) After switching on, the stove tries to start the burner - you hear a running fan and the firing electrode, and you can see gas intake on the home gas meter. I know that the electrode is sparking, because I started the boiler with the igniter in my hand and you can see that it is sparking (of course the gas was turned off).

2) Once every 10-15 attempts, the boiler fires up, but this firing up takes quite a long time. Normally, it takes about 0.5-1 seconds to ignite the flame, and in my case it takes about 2-3 seconds. This is how long you can hear the sparking of the fuse and an attempt to ignite it. Additionally, the ignition itself takes place in two stages - that is, you can hear two separate gas explosions

3) And here the puzzle begins, because sometimes the boiler ignites in this 3 second, it literally goes out after a while (in the fourth second) and the fan reduces its speed again to repeat the attempt to start the ignition

4) In most cases, the boiler repeats the ignition attempt, probably 5 times, and if it does not ignite even once, it causes error F4. When ignition occurs (temporary for about 1 second), the boiler falls into a loop of attempts to ignite.

What I did to improve it were the activities described in the service manual from pages 24 to 29, so:
- I dismantled the entire burner, dismantled it completely and cleaned it
- I cleaned the heating surfaces of the stove (vacuuming + brushing the surface and rinsing with plenty of water)
- I cleaned the entire air supply duct (from the Wenturi duct, through the fan to the radiator)
- I cleaned the condensate drain
- I cleaned the ignition electrode at the sparking point with 320 grit sandpaper and tried several different electrode gap settings
- I reset the boiler according to page 36 of the manual
- Additionally, I cleaned the gas filter before entering the stove.
- I checked that the voltage to the boiler was supplied according to the requirements - i.e. phase to L1 connector, Neutral to N, and ground to ground.


The boiler is powered by propane gas from a cylinder.
The 2700l cylinder has a first stage reducer with a range of 0-3 bar, whose manometer (possibly damaged) shows about 4.5 bar.
Then I have a second stage reducer reducing to 37mbar, which has visible traces of sticky deposit in the area of the relief valve.

This whole thing raises the following questions for me:
1) Why does the boiler have ignition problems (it works for about half a year, but after the warranty)?
2) What causes the problem with the flame retention and that the boiler goes out right after ignition?
3) If the 2nd stage reducer gives a pressure other than 37mbar, can the boiler have problems with keeping the flame and igniting the flame itself?
4) What do you propose to start in this situation - from the boiler review (assumingthat the inlet pressure is correct), or from the replacement of the 1-stage reducer on the cylinder and the pressure control after the 2nd reducer?
5) Can the problems with the flame and ignition be influenced by bad composition of exhaust gases, residual CO2 value?
6) The service manual presents the ignition electrode as a wear-out element, but I do not understand what can wear out if there are only two appropriately shaped wires? Can cleaning the electrode with sandpaper damage it in any way? Below is a photo of my electrode after cleaning with sandpaper.





I enclose the assembly and service instructions:
https://www.elektroda.pl/rtvforum/files-rtvfo...t_a_viessmann_-_model_vitodens_100-w_1744.pdf

The minimum pressure of LPG AT THE CONNECTION (: I) is to be 42.5 mbar (at the flow for maximum power) but not more than 57.5 mbar. This is the basis. If it is otherwise, the LPG system must be cleaned (call the LPG supplier's service). Then check the composition of exhaust gases (it should be as the manufacturer writes) and other service settings for this boiler when converting it from natural gas to liquid gas.

And not 37-42 mbar at the entrance?

Yes Yes Sunday sluggish day.

ok, so assuming that the 2nd stage reducer is operational, it has been correctly selected.

What do you think about the problems with ignition and flame retention?

There is no need to judge, but you need to check the pressure. gas in front of the boiler as described above. The inscription on the gas regulator does not guarantee that it is in front of the boiler.

I invited a service technician who connected the analyzer and it turned out that:

- pressure downstream of the 2nd degree reducer (37mbar), i.e. on the boiler feed, is 41mbar, i.e. CORRECT
- the pressure on the burner was about 2 bar (I don't remember exactly) but it was CORRECT
- the control probe of the flue gas analyzer at the chimney outlet has been inserted, confirmed that the fumes leave the chimney correctly and do not return to the "suction" of air => CORRECTLY
- CO2 content it should be 8.7% and it was 7.3%. INCORRECT

Adjusting the mixture (ie increasing the amount of gas in the mixture) gave a positive effect, because the boiler started to ignite after the first "explosion" and so far it fires correctly.

So the case looks resolved.

According to the service technician, the cause of the ignition problem could be excess air in the mixture, which could cause the flame to blow out.

In this case, I would also like to ask about the electrode itself - is it actually sputtered with some additional metal, or is the wire properly shaped to a homogeneous one?

The service technician suggested to clean it very gently to remove the dirt, without destroying the sputtered surface, because after starting the boiler, the ignition electrode measures the ionization current


______

As for the sediment at the 2nd stage reducer, the installer called me back and said that the reducer has a small drain valve that opens sometimes and releases excess pressure, especially when, for example, gas is not used at home and the pressure in the pipeline begins to increase (e.g. as a result of an increase in gas temperature in the pipeline).

marc07 wrote:

In this case, I would also like to ask about the electrode itself - is it actually sputtered with some additional metal ..

Yes, a titan.

Quote:

marc07 wrote:
In this case, I would also like to ask about the electrode itself - is it actually sputtered with some additional metal ..

Quote:

Yes, a titan.

So cleaning with sandpaper probably caused the destruction of this surface.
And how does the destruction of this surface translate into the measurement of the ionization current?
Can you expect a measurement error that is significant, or will the error be insignificant and should not be concerned?

In the instructions on the electrode in the topic called "The stove does not start" it says to clean with sandpaper, and now as I know that there is titanium dust, it seems reasonable to clean it ........... what?

Spirit, gently CIF, or some special non-abrasive agent that will not wipe off the titanium?

I will close the topic when I replace the pressure gauge on the 1 stage reducer, and I will make sure whether it is only the manometer is damaged or the reductor. I will describe the effects in this thread.

marc07 wrote:

And how does the destruction of this surface translate into the measurement of the ionization current?
Can you expect a measurement error that is significant, or will the error be insignificant and should not be concerned?

In the instructions on the electrode in the topic called "The stove does not start" it says to clean with sandpaper

It will not affect the current measurement, only shorten its life time. Cleaning with sandpaper is a mistake. This can be done gently with a copper cleaner, but this is a temporary solution. The electrode should be replaced with a new one.

Quote:

Quote:

marc07 wrote:
And how does the destruction of this surface translate into the measurement of the ionization current?
Can you expect a measurement error that is significant, or will the error be insignificant and should not be concerned?

In the instructions on the electrode in the topic called "The stove does not start" it says to clean with sandpaper

Quote:

It will not affect the current measurement, only shorten its life time. Cleaning with sandpaper is a mistake. This can be done gently with a copper cleaner, but this is a temporary solution. The electrode should be replaced with a new one.

Thank you very much for this valuable information!

At the same time, I propose to change the entry in the sticky thread https://www.elektroda.pl/rtvforum/topic938269.html

If the boiler does not want to ignite and the ignition electrodes are constantly giving a spark, then the electrode is most likely very dirty.
Please clean it e.g. with sandpaper or a brass wire brush and check that it is properly heated by the flame.

Walker29 wrote:

The value of CO2 in the exhaust gas should be in the range of 7.5-10.5% (how to set and what exactly the values should be are given in the manual),

For E gas, and for propane it should be 10-12%

It's okay. Relax ...

Walker29 wrote:

All in all right. The analyzer does not measure CO2 anyway, but oxygen. I wrote its boundaries correctly.

But you hit a few bugs anyway

@ Walker29

Quote:

I suggest that you deal with this topic at the beginning because there are many wrong diagnoses here! Users who experience a similar problem in the future will copy the query author's errors.


1. The electrode in the Vitodens 100-W does not measure the ionization current. It is only a ignition electrode with a flame detector (measures nothing).
2. Gas pressure is not measured with the analyzer.
3. Pressure on the burner ... - I don't know what it is, probably the author used the wrong expression (it was about the pressure in the central heating system)
4. There are two gas supply pressures:

For liquefied gas, the static pressure should not exceed 57mbar, and the dynamic pressure within the range of 36-45.

5. We perform the flue gas analysis with a tightly closed housing.

The value of CO2 in the exhaust gas should be in the range of 7.5-10.5% (how to set and what exactly the values should be given in the manual), ppm of CO does not exceed 100, oxygen 4.4-6.6% (this results in the CO2).

6.If the CO2 content in the exhaust gas was 7.3%, then the increase in the amount of gas would not improve the situation, and it should actually work the other way around (it seems that either the service got dark or the author screwed up something - after all, he does not have to know everything)

7. Since the electrode does not measure anything, you can clean it yourself, but what will it do if we do not clean the boiler? (These electrodes do not wear out, as in the Vitodens 200 or 300 boiler - info for insiders and owners).

Feels called to the board ... so I explain ....

Ad1. Perhaps I twisted something in this regard, but note that I myself was not sure that this electrode could measure something, hence my request in this thread for someone to confirm it. Speaking of the electrode itself ... how does the boiler detect a flame with this electrode? Since the spark crosses about 4-5mm, I suppose that high voltage is applied to the electrode during firing. But how does the boiler check that the flame is already burning on the basis of the same electrode?

Ad2. Perhaps I used a mental shortcut. The device that the service technician had was an "all in one" device. It was the only device that was tested by the boiler, so you are right - I should write that it did not test with an analyzer, but with a multifunctional diagnostic device (unless it is called somehow specialized)

Ad3. The service technician checked the pressure in 2 places shown in the photo below. First, he loosened the screw on the left side of the regulator and checked the inlet pressure (after the measurement he closed it), then he loosened the screw on the right side of the regulator and measured the pressure at the inlet to the combustion chamber (i.e. the regulator outlet).


Ad4. In fact, he measured these two pressures, i.e. static (when the boiler does not use gas and does not heat up) i dynamic checked during firing, operation and shutdown. Here I also used a mental shortcut - I should write that both dynamic and static pressures were correct.

Ad5. The measurement was performed with the boiler casing open. There is no written information in the manual that it should be performed with the housing closed. So why is it necessary to measure with a closed housing? This casing is not tight from the bottom anyway, because the cut air is taken from the bottom slots of the boiler.

Ad6. What you wrote in this point is very debatable for me, because
-first, in the service manual it is stated that the boiler should be adjusted to the CO2 value equal to 8.7% (and I saw such results on the analyzer; this result was visible for the 1st line of the boiler, with increasing the power it increased slightly)
- secondly, from what I know is the correct selection of the mixture composition, it is reflected in the appropriate composition of the exhaust gases and translates into the proper efficiency of the boiler.

Ad7. Here, my friend, you haven't read the beginning of the post - the boiler from the air inlet to the combustion chamber was completely cleaned. The electrode was also cleaned, but from what I found out, I think I was cleaning it the wrong way, because I probably wiped the titanium on it.

Anyway, the point on cleaning the electrode is also described in the manual -page 26 (quote below).
"Clean the electrode with a small brush (do not use a wire brush) or sandpaper."

Only it is written so that it can be misunderstood a bit
In my opinion, it should be written more clearly.

"Clean the electrode with a small brush or sandpaper. Do not use a wire brush "

because someone can understand it like this ...

"Clean the electrode with a small brush. Do not use a wire brush or sandpaper "

Quote:

As for the author [...] However, you should not do anything alone.

My friend, I am responsible for the pipelines in which gas, petrol and other dangerous substances flow in a very large factory. I am not authorized to repair boilers, but I do have knowledge of safety, mechanics and electronics. In short, I am not an accidental "Mak gajwer" but professionally I deal with much more dangerous installations. I just missed a boiler control device to check it, and a bit of a focused boiler viewer.

But I understand your concern perfectly well - I would write that too, because rummaging in the boiler by people who do not know the dangers may end tragically, so I have no complaints.

marc07 wrote:

firstly, in the service manual it is stated that the boiler should be adjusted to the CO2 value equal to 8.7%

Yes, but this is written in the service manual for the natural gas boiler. But there is also an instruction on converting this boiler to LPG. And there it is already talking about 10-12% CO2. But you didn't have to know about that either. Your service technician didn't have to either (although he should).

Walker29 wrote:

Please - replace.

Walker29 wrote:

1. The electrode in the Vitodens 100-W does not measure the ionization current. It is only a ignition electrode with a flame detector (measures nothing).

How does he feel if he doesn't measure it?

Walker29 wrote:

3. Burner pressure ... - I don't know what it is

Well, not in this boiler, but you know what is in the atmosphere

Walker29 wrote:

4. There are two gas supply pressures:
For liquefied gas, the static pressure should not exceed 57mbar, and the dynamic pressure within the range of 36-45.

You've already gone here It is clearly defined: 36-42 mbar, as for 2E-G20 17-25 mbar

Walker29 wrote:

5. We perform the flue gas analysis with a tightly closed housing.

I don't know about this boiler, but not all boilers. It is often performed with the chamber open and checked with the closed chamber. And it works :)

Unless I don't know something

@wawrzeczko_t

Quote:

But there is also an instruction on converting this boiler to LPG. And there it is already talking about 10-12% CO2

You're right buddy !!!
There are a total of 2 gas switch instructions
- one shows how to change from GZ 50 gas (because this is how the boiler is factory set) to natural gas GZ 41.5 or GZ 35
- the second shows how to change the factory settings from the GZ50 on Propane LPG
In the installation manual, there is an additional instruction to regulate CO2 for another gas - referenced by the blue arrow

Now I have to call the service technician and probably invite him again for a correction.







I attach both gas switch instructions - it may be useful to someone

For me, the situation was similar.

Symptoms: the boiler does not detect a flame, zero ionization current, start-stop loop and error messages "ignition failure".

Diagnosis: the loss of capacity in the capacitor feeding the ionization system from 220nf X2 / 275V remained less than 50nf.

The capacitor is easy to locate by following the "ground" wire from the ignition electrode (usually green-yellow).
Depending on the boiler, the condenser is located in the burner control unit at the gas valve or on the boiler main plate.

The capacity may be slightly different depending on the boiler model and manufacturer.

greetings
GREGOR

I'll refresh the topic. In my case, the ignition problems were caused by a gold-colored deposit (as in the photo below) in the channel where the ignition electrodes were installed. After the sediment was removed, the problem was resolved. I will try to unscrew the chamber and check, if necessary, clean the combustion chamber.
[img] [/ img]
PS: Hope it's gold
Added:
It turned out that the "golden" sediment is the material from which the thermal shields in the combustion chamber are made. Due to the lack of a condensate drain (the drain blocked), the water caused damage - swelling of the thermal shields. Blockage of the ionization and ignition electrodes.

I'll refresh the topic. For me, problems with ignition were also caused by sediment, but such a delicate electrode along the entire length - cleaning with a wire brush (the yellow one) helped, earlier after firing it did not want to heat the water, it turned off immediately.

You have to be able to separate the grain from the chaff!

marc07 wrote:

In this case, I would also like to ask about the electrode itself - is it actually sputtered with some additional metal ..

mirrzo wrote:

Yes, a titan.

I guess it would be American electrodes.
Titanium itself is a strategic, rare and expensive metal.
And these electrodes, commonly used in boilers, are simply stainless steel rods with the appropriate hardness, alloy structure to withstand continuous high temperature and not to rust.
And anyway, over time, these electrodes oxidize forming a rough layer, but it's not sputtering titanium ! These are the oxides that have a negative effect on the ionization measurement.
That is why we maintain them or replace them when they oxidize a lot.

marc07 wrote:

The service technician suggested to clean it very gently to remove the dirt, without destroying the sputtered surface, because after starting the boiler, the ignition electrode measures the ionization current

" the sprayed surface "! What kind of service technician, what kind of metallurgist? Better, as if he said, to gently clean, not to scratch or scratch the porcelain, as it may later accumulate contamination and as a result, shortcuts may be created - it would be a better use from his advice.

marc07 wrote:

Ad7. Here, my friend, you haven't read the beginning of the post - the boiler from the air inlet to the combustion chamber was completely cleaned. The electrode was also cleaned, but from what I found out, I think I was cleaning it the wrong way, because I probably wiped the titanium on it.

The electrodes are to be "cleaned" properly d with a metallic sheen (as if they were new), then the ionization measurement will be the best.
Buddy, you definitely didn't " sputtered titanium "but you only removed the oxides that accumulated increased the resistance to current, ionization.
In a word, you did very well by cleaning it to a metallic sheen. It will probably withstand more than 2 heating seasons.

I have the same problem, the boiler is trying to start
1. there is a spark (twice)
2nd fan changes speed
3. there is voltage on the gas valve coil (also twice), but only for a very short time
The entire cycle takes about a minute and an F: 4 error is displayed

I am adding info from the Vitodens 100 website on how to clean the electrodes:
wire brush: NO
sandpaper:YES

In my case, the electrode, probably due to the temperature, was deformed and "sagged" by gravity, as a result of which the distance between the terminals increased - the result: no spark. Bending the electrodes helped, but it must be done hot, after heating with a burner, otherwise there is a risk of crumbling the ceramic insulation. After setting a distance of approximately 4.5 mm, the stove starts.

I will ask here. I have a slightly different problem than the previous speakers. At my place, the cooker seemingly works normally. It fires up without any problems. But... In the summer, with the heating off, the water heating alone on, I top up the water from time to time, the pressure drops slightly. And here's the problem. Despite the heating being off, at zero, the cooker fires the burner and displays the heating icon. Moving the heating knob to on/off does not help, it is only when I turn the cooker off with the button and then on again that I can use it to heat water as normal. No error messages are displayed. The service technician has apparently stated that the heating knob is faulty (I don't know if it is some kind of adjustable resistor?), and this cannot be replaced, the entire control unit has to be replaced.... And the price is known. Maybe some other ideas? I am an electrician, I will not look into the belly of the cooker, but maybe I can do something myself if it is something in the controller?