Vitodens 100 F1 Error: Flue Gas Temperature High After Service Checks—What Next?

Question

As in the topic, the error F1 appeared - too high temperature of exhaust gas. Service called and:
- burner checked
- exchanger cleaned
- exchanger descaled and flushed
- pump checked
- chimney checked - draught is
- CO2 in normal.
Nothing helped, still flue gas temperature too high and F1.
What else can be done, checked?

PS Installation probably froze last winter, now (November) worked 3 weeks without problems.

piracik · Answer

What exhaust temperature came out on the exhaust analysis?

Added after 5 [minutes]:

The flue gas temperature should be close to the temperature on the boiler.
Up to 10*C may be higher than that on the boiler.
If on the flue gas analysis the temperature was within this range then the flue gas temperature sensor should be replaced.

Vitodens · Answer

The exhaust gas temperature on analysis reached 130-140 0C, so it's not the exhaust gas temperature sensor.

piracik · Answer

Diligently vent the boiler.

Vitodens · Answer

The boiler was vented, the pump also. Will try again.

piracik · Answer

On the exchanger you have such a white faucet. With a radiator vent key you can unscrew it.
Place some hose on it if there is none and let some water out in a few cycles.
You can do this on the boiler pump on.

Anonymous · Answer

Rather, the flue gas temp indicates a lack of heat collection(no flow through the exchanger, or chimney problems).

Vitodens · Answer

Venting did not help - I did twice.

As I wrote earlier exchanger decalcified, flushed, chimney checked "draught" good - so it's not that.

As ideas run out we will try to put in the second exchanger and see if that helps.

Anonymous · Answer

And do you have such an exchanger ?

Vitodens · Answer

I don't have one, but the SERVICEMAN is supposed to have one.

Anonymous · Answer

Such an exchanger costs as much as a new boiler. How did you check the chimney and what draught do you write about in a boiler with a fan ?

Vitodens · Answer

The exchanger is from a dismantled boiler.
The draught in the flue was measured above the boiler (two holes in the outlet pipe) with a sensor with which CO2, flue gas temperature, O2, etc. were also measured.

Nargo · Answer

Check the filter before the boiler yet. A simple fault and it can mess up a lot .

Vitodens · Answer

The filter in front of the boiler clean.

swornegacie · Answer

And how is the problem solved?

saskia · Answer

Are the radiators heating correctly? How was the pump checked?

Vitodens · Answer

The problem is not solved. When the furnace is running (set to minimum temperature), all radiators are heating. The pump was replaced with a new one.

saskia · Answer

I suspect that you have very long and too thin risers, and the last radiator is quite far from the boiler.
If the installation froze early, it is most likely that any impurities such as scale, rust, etc. were crushed and detached to the inner surfaces of the installation.
You must check all flows on the entire system, but it would be best to flush it under pressure from the mains, in the opposite direction to the CH flow.
Of course, you would have to disconnect the boiler before doing so.

Vitodens · Answer

Maybe I will try to flush, but if the installation was obstructed and the water was slow flowing then the water temperature on the stove would rise very quickly, and nothing like that happens. Unless I am deducing wrong?

saskia · Answer

At a minimum temp. radiators give off heat more slowly (less "gravitational pull" in the radiators) and then it spreads to all radiators more evenly.
If the temperature is high, the first radiators give off a lot of heat and then there is a greater "draught" on them, so that further radiators do not heat up as quickly as the first.

piracik · Answer

In my opinion, the problem does not lie in too little circulation. Where are you mate?

saskia · Answer

Me, or the author of the topic? .

piracik · Answer

Good If the distance was within reason, I would love to see such a cauldron what someone has already at it fell Have you done a test on another exchanger? Now it still occurred to me. If the exchanger froze then it may also have deformed quality. If it deformed then the gaps between the coils of the pipe may have increased making the exhaust gas flow faster giving less heat to the exchanger. The temperature on the boiler in such a case would reach a low temperature and the temperature of the flue gas would be very high. I think this theory is very likely. .

Vitodens · Answer

Mlawa - a little far away Unfortunately no, it's hard to get a new exchanger without paying for it. The gaps we checked, only in two places are minimally above normal.

piracik · Answer

For.

dario0 · Answer

There is no way that the coils of the heat exchanger, then it would push the alu side rings and gaskets - so there would be condensate or flue gases.
It is impossible that the temperature of exhaust gases in this boiler reached 140 degrees.
Or no flow or faulty gas fittings and let too much gas through, but this should come out in the analysis of exhaust.

piracik · Answer

You see seemingly the possibility of such a thing, and yet the temperature is there.
To make the gaps larger does not have to push the rings. It is enough that some are widened and others narrowed.
Or, for example, the diameter of the coils will change.

dario0 · Answer

There is no such possibility. !

piracik · Answer

So what is the cause of this fault?

_uki_ · Answer

check the nozzles, whether they are sized for the gas you have in the network (or cylinder), the gas pressure after the gas block, the amount of gas burned at max/min power. air vents, birds in the chimney, etc.

at worst, the motherboard

Vitodens 100 F1 Error: Flue Gas Temperature High After Service Checks—What Next?

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